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Silver Based Materials

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Pure silver (also called fine silver) exhibits the highest electrical and thermal conductivity of all metals. It is also resistant against oxidation. Major disadvantages are its low mechanical wear resistance, the low softening temperature, and especially its strong affinity to sulfur and sulfur compounds. In the presence of sulfur and sulfur containing compounds brownish to black silver sulfide layer are formed on its surface. These can cause increased contact resistance or even total failure of a switching device if they are not mechanically, electrically, or thermally destroyed. Other weaknesses of silver contacts are the tendency to weld under the influence of over-currents and the low resistance against material transfer when switching DC loads. In humid environments and under the influence of an electrical field silver can creep (silver migration) and cause electrical shorting between adjacent current paths.
<xr id="tab:Overview_of_the_Most_Widely_Used_Silver_Grades"/><!--(Table 2.11 )--> shows the typically available quality grades of silver. In certain economic areas, i.e. China, there are additional grades with varying amounts of impurities available on the market. In powder form silver is used for a wide variety of silver based composite contact materials. Different manufacturing processes result in different grades of Ag powder as shown in <xr id="tab:Quality_Criteria_of_Differently_Manufactured_Silver_Powders"/><!--Table 2.12-->. additional Additional properties of silver powders and their usage are described in chapter [[ Precious Metal Powders and Preparations#Precious_Metal_Powders|Precious Metal Powders ]] und [[Precious_Metal_Powders_and_Preparations|Table Different Types of Silver Powders.]]<!--(Tab. 8.1.)--> Semi-finished silver materials can easily be warm or cold formed and can be clad to the usual base materials(<xr id="fig:Strain hardening of Ag bei cold working"/> and <xr id="fig:Softening of Ag after annealing after different degrees"/>). For attachment of silver to contact carriermaterials welding of wire or profile cut-offs and brazing are most widely applied. Besides these mechanical processes such as wire insertion (wire staking) and the riveting (staking) of solid or composite contact rivets are used in the manufacture of contact components.
Contacts made from fine silver are applied in various electrical switching devices such as relays, pushbuttons, appliance and control switches for
currents < 2 A ''(<xr id="tab:Application Examples and Forms of Supply for Silver and Silver Alloys"/>)<!--(Table 2.16)''-->. Electroplated silver coatings are widely used to reduce the contact resistance and improve the brazing behavior of other contact materials and components.
'''Table 2.11: Overview of the Most Widely Used Silver Grades'''
<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s12">Designation</p></td><td><p class="s12">Composition minimum Ag [wt%]</p></td><td><p class="s12">Impurities</p><p class="s12">[ppm]</p></td><td><p class="s12">Notes on Usage</p></td></tr><tr><td><p class="s12">Spectroscopically</p><p class="s12">Pure Ag</p></td><td><p class="s11">99.999</p></td><td><p class="s11">Cu &lt; 3</p><p class="s11">Zn &lt; 1</p><p class="s11">Si &lt; 1</p><p class="s11">Ca &lt; 2</p><p class="s11">Fe &lt; 1</p><p class="s11">Mg &lt; 1</p><p class="s11">Cd &lt; 1</p></td><td><p class="s12">Sheets, strips, rods, wires for electronic applications</p></td></tr><tr><td><p class="s12">High Purity Ag, oxygen-free</p></td><td><p class="s11">99.995</p></td><td><p class="s11">Cu &lt; 30</p><p class="s11">Zn &lt; 2</p><p class="s11">Si &lt; 5</p><p class="s11">Ca &lt; 10</p><p class="s11">Fe &lt; 3</p><p class="s11">Mg &lt; 5</p><p class="s11">Cd &lt; 3</p></td><td><p class="s12">Ingots, bars, granulate for alloying</p><p class="s12">purposes</p></td></tr></table>
<figtable id="tab:Overview_of_the_Most_Widely_Used_Silver_Grades"><caption>'''<!--Table 2.1211: Quality Criteria -->Overview of Differently Manufactured the Most Widely Used Silver PowdersGrades'''</caption><table class="twocolortable"><tr><th><p class="s12">Designation</p></th><th><p class="s12">Composition minimum Ag [wt%]</p></th><th><p class="s12">Impurities</p><p class="s12">[ppm]</p></th><th><p class="s12">Notes on Usage</p></th></tr><tr><td><p class="s12">Spectroscopically</p><p class="s12">Pure Ag</p></td><td><p class="s11">99.999</p></td><td><p class="s11">Cu &lt; 3</p><p class="s11">Zn &lt; 1</p><p class="s11">Si &lt; 1</p><p class="s11">Ca &lt; 2</p><p class="s11">Fe &lt; 1</p><p class="s11">Mg &lt; 1</p><p class="s11">Cd &lt; 1</p></td><td><p class="s12">Sheets, strips, rods, wires for electronic applications</p></td></tr><tr><td><p class="s12">High Purity Ag, oxygen-free</p></td><td><p class="s11">99.995</p></td><td><p class="s11">Cu &lt; 30</p><p class="s11">Zn &lt; 2</p><p class="s11">Si &lt; 5</p><p class="s11">Ca &lt; 10</p><p class="s11">Fe &lt; 3</p><p class="s11">Mg &lt; 5</p><p class="s11">Cd &lt; 3</p></td><td><p class="s12">Ingots, bars, granulate for alloying purposes</p><p class="s12"></p></td></tr></table></figtable>
Fig. 2.45: Strain hardening of Ag 99.95 by cold working
[[File:Strain hardening of Ag bei cold working.jpg|right|thumb|Strain hardening of Ag 99.95 bei cold working]]
Fig<figtable id="tab:Quality_Criteria_of_Differently_Manufactured_Silver_Powders"><caption>'''<!--Table 2. 12:-->Quality Criteria of Differently Manufactured Silver Powders'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!colspan="2" |Impurities !Ag-Chem.46*!Ag-ES**!Ag-V***|-|Cu |ppm|< 100|< 300|< 300|-|Fe |ppm|< 50|< 100|< 100|-|Ni |ppm|< 50|< 50|< 50|-|Cd |ppm|||< 50|-|Zn |ppm|||< 10|-|Na + K + Mg + Ca |ppm|< 80|< 50|< 50|-|Ag CI |ppm|< 500|< 500|< 500|-|NO<sub>3</sub> |ppm|< 40|< 40||-|Nh<sub>4</sub>CI |ppm|< 30|< 30||-!colspan="5" |Particle Size Distribution (screen analysis)|-|> 100 μm |%|0|0|0|-|< 100 bis > 63 μm |%|< 5|< 5|< 15|-|< 36 μm |%|< 80|< 90|< 75|-|Apparent Density |g/cm<sup>3</sup>|1.0 - 1.6|1.0 - 1.5|3 - 4|-|Tap Density |ml/100g|40 - 50|40 - 50|15 - 25|-!colspan="5" |Press/Sintering Behavior|-|Press Density |g/cm<sup>3</sup>|5.6 - 6.5|5.6 - 6.3|6.5 - 8.5|-|Sinter Density |g/cm<sup>3</sup>|> 9|> 9.3|> 8|-|Volume Shrinkage |%|> 34|> 35|> 0|-|Annealing Loss|%|< 2|< 0.1|< 0.1|}</figtable> <nowiki>*</nowiki> Manufactured by chemical precipitation <br /><nowiki>**</nowiki> Manufactured by electrolytic deposition <br /><nowiki>***</nowiki> Manufactured by atomizing of a melt  <div class="multiple-images"> <figure id="fig:Strain hardening of Ag bei cold working">[[File: Softening Strain hardening of Ag bei cold working.jpg|left|thumb|<caption>Strain hardening of Ag 99.95 - cold working</caption>]]</figure> <figure id="fig:Softening of Ag after annealing for 1 hr after different degrees of strain hardening">[[File:Softening of Ag after annealing after different degrees.jpg|rightleft|thumb|<caption>Softening of Ag 99.95 after annealing for 1 hr after different degrees of strain hardening</caption>]]</figure></div><div class="clear"></div>
===Silver Alloys===
To improve the physical and contact properties of fine silver , melt-metallurgical produced silver alloys are used ''(<xr id="tab:Physical Properties of Silver and Silver Alloys"/>)<!--(Table 2.13)''-->. By adding metal components , the mechanical properties such as hardness and tensile strength as well as typical contact properties such as erosion resistance, and resistance against material transfer in DC circuits are increased ''(<xr id="tab:Mechanical Properties of Silver and Silver Alloys"/>)<!--(Table 2.14)''-->. On the other hand however, other properties such as electrical conductivity and chemical corrosion resistance can be negatively impacted by alloying ''(Figs<xr id="fig:Influence of 1 10 atom of different alloying metals"/><!--(Fig. 2.47 )--> and <xr id="fig:Electrical resistivity p of AgCu alloys"/>)<!--(Fig. 2.48)-->. <figtable id="tab:Physical Properties of Silver and Silver Alloys"><caption>'''<!--Table 2.13:-->Physical Properties of Silver and Silver Alloys'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Silver Content<br />[wt%]!Density<br />[g/cm<sup>3</sup>]!Melting Point<br />or Range<br />[°C]!Electrical<br />Resistivity<br />[μΩ·cm]!Electrical<br />Conductivity<br />[MS/m]!Thermal<br />Conductivity<br />[W/mK]!Temp. Coefficient of<br />the Electr.Resistance<br />[10<sup>-3</sup>/K]!Modulus of<br />Elasticity<br />[GPa]|-|Ag|99.95|10.5|961|1.67|60|419|4.1|80|-|AgNi0.15|99.85|10.5|960|1.72|58|414|4.0|82|-|AgCu3|97|10.4|900 - 938|1.92|52|385|3.2|85|-|AgCu5|95|10.4|910|1.96|51|380|3.0|85|-|AgCu10|90|10.3|870|2.0|50|335|2.8|85|-|AgCu28|72|10.0|779|2.08|48|325|2.7|92|-|Ag98CuNi<br />ARGODUR 27|98|10.4|940|1.92|52|385|3.5|85|-|AgCu24.5Ni0.5|75|10.0|805|2.20|45|330|2.7|92|-|Ag99.5NiMg<br />ARGODUR 32<br />Not heat treated|99.5|10.5|960|2.32|43|293|2.3|80|-|ARGODUR 32<br />Heat treated|99.5|10.5|960|2.32|43|293|2.1|80|}</figtable> <div class="multiple-images"> <figure id="fig:Influence of 1 10 atom of different alloying metals">[[File:Influence of 1 10 atom of different alloying metals.jpg|left|thumb|<caption>Influence of 1-10 atom% of different alloying metals on the electrical resistivity of silver</caption>]]</figure> <figure id="fig:Electrical resistivity p of AgCu alloys">[[File:Electrical resistivity p of AgCu alloys.jpg|left|thumb|<caption>Electrical resistivity p of AgCu alloys with 0-20 weight% Cu in the soft annealed and tempered stage a) Annealed and quenched b) Tempered at 280°C</caption>]]</figure></div><div class="clear"></div> <figtable id="tab:Mechanical Properties of Silver and Silver Alloys"><caption>'''<!--Table 2.14:-->Mechanical Properties of Silver and Silver Alloys'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p></th><th><p class="s12">Hardness</p><p class="s12">Condition</p></th><th><p class="s12">Tensile Strength</p><p class="s12">R<span class="s31">m </span>[MPa]</p></th><th><p class="s12">Elongation A [%] min.</p></th><th><p class="s12">Vickers Hardness</p><p class="s12">HV 10</p></th></tr><tr><td><p class="s12">Ag</p></td><td><p class="s12">R 200</p><p class="s12">R 250</p><p class="s12">R 300</p><p class="s12">R 360</p></td><td><p class="s12">200 - 250</p><p class="s12">250 - 300</p><p class="s12">300 - 360</p><p class="s12">&gt; 360</p></td><td><p class="s12">30</p><p class="s12">8</p><p class="s12">3</p><p class="s12">2</p></td><td><p class="s12">30</p><p class="s12">60</p><p class="s12">80</p><p class="s12">90</p></td></tr><tr><td><p class="s12">AgNi0.15</p><p class="s12"></p></td><td><p class="s12">R 220</p><p class="s12">R 270</p><p class="s12">R 320</p><p class="s12">R 360</p></td><td><p class="s12">220 - 270</p><p class="s12">270 - 320</p><p class="s12">320 - 360</p><p class="s12">&gt; 360</p></td><td><p class="s12">25</p><p class="s12">6</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">40</p><p class="s12">70</p><p class="s12">85</p><p class="s12">100</p></td></tr><tr><td><p class="s12">AgCu3</p></td><td><p class="s12">R 250</p><p class="s12">R 330</p><p class="s12">R 400</p><p class="s12">R 470</p></td><td><p class="s12">250 - 330</p><p class="s12">330 - 400</p><p class="s12">400 - 470</p><p class="s12">&gt; 470</p></td><td><p class="s12">25</p><p class="s12">4</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">45</p><p class="s12">90</p><p class="s12">115</p><p class="s12">120</p></td></tr><tr><td><p class="s12">AgCu5</p></td><td><p class="s12">R 270</p><p class="s12">R 350</p><p class="s12">R 460</p><p class="s12">R 550</p></td><td><p class="s12">270 - 350</p><p class="s12">350 - 460</p><p class="s12">460 - 550</p><p class="s12">&gt; 550</p></td><td><p class="s12">20</p><p class="s12">4</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">55</p><p class="s12">90</p><p class="s12">115</p><p class="s12">135</p></td></tr><tr><td><p class="s12">AgCu10</p></td><td><p class="s12">R 280</p><p class="s12">R 370</p><p class="s12">R 470</p><p class="s12">R 570</p></td><td><p class="s12">280 - 370</p><p class="s12">370 - 470</p><p class="s12">470 - 570</p><p class="s12">&gt; 570</p></td><td><p class="s12">15</p><p class="s12">3</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">60</p><p class="s12">95</p><p class="s12">130</p><p class="s12">150</p></td></tr><tr><td><p class="s12">AgCu28</p></td><td><p class="s12">R 300</p><p class="s12">R 380</p><p class="s12">R 500</p><p class="s12">R 650</p></td><td><p class="s12">300 - 380</p><p class="s12">380 - 500</p><p class="s12">500 - 650</p><p class="s12">&gt; 650</p></td><td><p class="s12">10</p><p class="s12">3</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">90</p><p class="s12">120</p><p class="s12">140</p><p class="s12">160</p></td></tr><tr><td><p class="s12">Ag98CuNi</p><p class="s12">ARGODUR 27</p></td><td><p class="s12">R 250</p><p class="s12">R 310</p><p class="s12">R 400</p><p class="s12">R 450</p></td><td><p class="s12">250 - 310</p><p class="s12">310 - 400</p><p class="s12">400 - 450</p><p class="s12">&gt; 450</p></td><td><p class="s12">20</p><p class="s12">5</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">50</p><p class="s12">85</p><p class="s12">110</p><p class="s12">120</p></td></tr><tr><td><p class="s12">AgCu24,5Ni0,5</p></td><td><p class="s12">R 300</p><p class="s12">R 600</p></td><td><p class="s12">300 - 380</p><p class="s12">&gt; 600</p></td><td><p class="s12">10</p><p class="s12">1</p></td><td><p class="s12">105</p><p class="s12">180</p></td></tr><tr><td><p class="s12">Ag99,5NiMg</p><p class="s12">ARGODUR 32</p><p class="s12">Not heat treated</p></td><td><p class="s12">R 220</p><p class="s12">R 260</p><p class="s12">R 310</p><p class="s12">R 360</p></td><td><p class="s12">220</p><p class="s12">260</p><p class="s12">310</p><p class="s12">360</p></td><td><p class="s12">25</p><p class="s12">5</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">40</p><p class="s12">70</p><p class="s12">85</p><p class="s12">100</p></td></tr><tr><td><p class="s12">ARGODUR 32 Heat treated</p></td><td><p class="s12">R 400</p></td><td><p class="s12">400</p></td><td><p class="s12">2</p></td><td><p class="s12">130-170</p></td></tr></table></figtable>
Fig. 2.47: Influence of 1-10 atom% of different alloying metals on the electrical resistivity of silver
[[File:Influence of 1 10 atom of different alloying metals.jpg|right|thumb|Influence of 1-10 atom% of different alloying metals on the electrical resistivity of silver]]
Fig. 2.48:
[[File:Electrical resistivity p of AgCu alloys.jpg|right|thumb|Electrical resistivity p of AgCu alloys with 0-20 weight% Cu in the soft annealed and tempered stage a) Annealed and quenched b) Tempered at 280°C]]
====Fine-Grain Silver====
Fine-Grain Silver (ARGODUR-Spezial) silver is defined as a silver alloy with an addition of 0.15 wt% of Nickelnickel. Silver and nickel are not soluble in each other in solid form. In liquid silver , only a small amount of nickel is soluble as the phase diagram ''illustrates (<xr id="fig:Phase diagram of silver nickel"/><!--(Fig. 2.51)'' illustrates-->). During solidification of the melt , this nickel addition gets finely dispersed in the silver matrix and eliminates the pronounce coarse grain growth after prolonged influence of elevated temperatures ''(Figs<xr id="fig:Coarse grain micro structure of Ag"/><!--(Fig. 2.49 )--> and <xr id="fig:Fine grain microstructure of AgNiO"/><!--(Fig. 2.50)''-->).
Fig. 2.49: Coarse grain micro structure of Ag 99.97 after 80% cold working and 1 hr annealing at 600°C[[File:Coarse grain micro structure of Ag.jpg|right|thumb|Coarse grain micro structure of Ag 99.97 after 80% cold working and 1 hr annealing at 600°C]]<div class="multiple-images">
Fig. 2.50<figure id="fig: Fine Coarse grain microstructure micro structure of AgNi0.15 after 80% cold working and 1 hr annealing at 600°CAg">[[File:Fine Coarse grain microstructure micro structure of AgNiOAg.jpg|rightleft|thumb|Fine <caption>Coarse grain microstructure micro structure of AgNi0Ag 99.15 97 after 80% cold working and 1 hr annealing at 600°C</caption>]]</figure>
<figure id="fig:Fine grain microstructure of AgNiO">[[File:Fine grain microstructure of AgNiO.jpg|left|thumb|<caption>Fine grain microstructure of AgNi0.15 after 80% cold working and 1 hr annealing at 600°C</caption>]]</figure> <figure id="fig:Phase diagram of silver nickel">[[File:Phase diagram of silver nickel.jpg|left|thumb|<caption>Phase diagram of silver nickel</caption>]]</figure></div><div class="clear"></div> Fine-grain Grain silver has almost the same chemical corrosion resistance as fine silver. Compared to pure silver , it exhibits a slightly increased hardness andtensile strength ''(<xr id="tab:Mechanical Properties of Silver and Silver Alloys"/><!--(Table 2.14)''-->). The electrical conductivity is just slightly decreased by this low nickel addition. Because of its significantly improved contact properties , fine grain silver has replaced pure silver in many applications.
====Hard-Silver Alloys====
Using copper as an alloying component increases the mechanical stability of silver significantly(<xr id="fig:Strain hardening of AgCu3 by cold working"/>, <xr id="fig:Softening of AgCu3 after annealing"/> and <xr id="fig:Strain hardening of AgCu5 by cold working"/>). The most important among the binary AgCu alloys is that of AgCu3, known in europe also under the name of known as hard-silver. This material still has a chemical corrosion resistance close to that of fine silver. In comparison to pure silver and fine-grain silver , AgCu3 exhibits increased mechanical strength as well as higher arc erosion resistance and mechanical wear resistance ''(Table 2.14)''.
Increasing the Cu content further also increases the mechanical strength of AgCu alloys and improves arc erosion resistance and resistance against material transfer while at the same time however simultaneously the tendency to oxide formation becomes detrimental. This causes - during switching under arcing conditions - an increase in contact resistance with rising numbers of operation. In special applications , where highest mechanical strength is recommended and a reduced chemical resistance can be tolerated, the eutectic AgCu alloy with 28 wt% of copper ''is used (<xr id="fig:Phase diagram of silver copper"/>)<!--(Fig. 2.52)'' is used-->. AgCu10 , also known as coin silver , has been replaced in many applications by composite silver-based materials while sterling silver (AgCu7.5) has never extended its important usage from decorative table wear and jewelry to industrial applications in electrical contacts.
Besides these binary alloys, ternary AgCuNi alloys are used in electrical contact applications. From this group , the material ARGODUR 27, an alloy of 98 wt% Ag with a 2 wt% Cu and nickel addition has found practical importance close to that of AgCu3. This material is characterized by high resistance to oxidation and low tendency to re-crystallization during exposure to high temperatures. Besides high mechanical stability this AgCuNi alloy also exhibits a strong resistance against arc erosion. Because of its high resistance against material transfer , the alloy AgCu24.5Ni0.5 has been used in the automotive industry for an extended time in the North American market. Caused by miniaturization and the related reduction in available contact forces in relays and switches , this material has been replaced widely because of its tendency to oxide formation.
The attachment methods used for the hard silver materials are mostly close to those applied for fine silver and fine grain silver.
Hard-silver alloys are widely used for switching applications in the information and energy technology for currents up to 10 A, in special cases also for higher current ranges ''(<xr id="tab:Application Examples and Forms of Supply for Silver and Silver Alloys"/>)<!--(Table 2.16)''-->. Dispersion hardened alloys of silver with 0.5 wt% MgO and NiO (ARGODUR 32) are produced by internal oxidation. While the melt-metallurgical alloy is easy to cold-work and form, the material becomes very hard and brittle after dispersion hardening. Compared to fine silver and hard-silver, this material has a greatly improved temperature stability and can be exposed to brazing temperatures up to 800°C without decreasing its hardness and tensile strength.Because of these mechanical properties and its high electrical conductivity ARGODUR 32 is mainly used in the form of contact springs that are exposed to high thermal and mechanical stresses in relays and contactors for aeronautic applications. <div class="multiple-images"> <figure id="fig:Phase diagram of silver copper"> [[File:Phase diagram of silver copper.jpg|left|thumb|<caption>Phase diagram of silver-copper</caption>]]</figure> <figure id="fig:Strain hardening of AgCu3 by cold working"> [[File:Strain hardening of AgCu3 by cold working.jpg|left|thumb|<caption>Strain hardening of AgCu3 by cold working</caption>]]</figure> <figure id="fig:Softening of AgCu3 after annealing"> [[File:Softening of AgCu3 after annealing.jpg|left|thumb|<caption>Softening of AgCu3 after annealing for 1 hr after 80% cold working</caption>]]</figure> <figure id="fig:Strain hardening of AgCu5 by cold working"> [[File:Strain hardening of AgCu5 by cold working.jpg|left|thumb|<caption>Strain hardening of AgCu5 by cold working</caption>]]</figure> <figure id="fig:Softening of AgCu5 after annealing"> [[File:Softening of AgCu5 after annealing.jpg|left|thumb|<caption>Softening of AgCu5 after annealing for 1 hr after 80% cold working</caption>]]</figure>  <figure id="fig:Strain hardening of AgCu 10 by cold working"> [[File:Strain hardening of AgCu 10 by cold working.jpg|left|thumb|<caption>Strain hardening of AgCu 10 by cold working</caption>]]</figure>  <figure id="fig:Softening of AgCu10 after annealing"> [[File:Softening of AgCu10 after annealing.jpg|left|thumb|<caption>Softening of AgCu10 after annealing for 1 hr after 80% cold working</caption>]]</figure>  <figure id="fig:Strain hardening of AgCu28 by cold working"> [[File:Strain hardening of AgCu28 by cold working.jpg|left|thumb|<caption>Strain hardening of AgCu28 by cold working</caption>]]</figure>  <figure id="fig:Softening of AgCu28 after annealing"> [[File:Softening of AgCu28 after annealing.jpg|left|thumb|<caption>Softening of AgCu28 after annealing for 1 hr after 80% cold working</caption>]]</figure>  <figure id="fig:Strain hardening of AgNi0.15 by cold working"> [[File:Strain hardening of AgNiO15 by cold working.jpg|left|thumb|<caption>Strain hardening of AgNiO15 by cold working</caption>]]</figure>  <figure id="fig:Softening of AgNi0.15 after annealing"> [[File:Softening of AgNiO15 after annealing.jpg|left|thumb|<caption>Softening of AgNiO15 after annealing</caption>]]</figure>
Dispersion hardened alloys <figure id="fig:Strain hardening of ARGODUR 27"> [[File:Strain hardening of ARGODUR 27.jpg|left|thumb|<caption>Strain hardening of silver with 0AgCu1.8Ni0.5 wt% MgO and NiO 2 (ARGODUR 3227) are produced by internal oxidation. While the melt-metallurgical alloy is easy to cold-work and form the material becomes very hard and brittle after dispersion hardening. Compared to fine silver and hard-silver this material has a greatly improved temperature stability and can be exposed to brazing temperatures up to 800°C without decreasing its hardness and tensile strength.working</caption>]]Because of these mechanical properties and its high electrical conductivity ??? ARGODUR 32 is mainly used in the form of contact springs that are exposed to high thermal and mechanical stresses in relays, and contactors for aeronautic applications.</figure>
'''Table 2<figure id="fig:Softening of ARGODUR 27 after annealing"> [[File:Softening of ARGODUR 27 after annealing.13: Physical Properties jpg|left|thumb|<caption>Softening of Silver and Silver Alloys'''AgCu1.8Ni0.2 (ARGODUR 27) after annealing for 1 hr after 80% cold working</caption>]]</figure></div><div class="clear"></div>
Fig. 2.51: Phase diagram of silver-nickel
[[File:Phase diagram of silver nickel.jpg|right|thumb|Phase diagram of silver nickel]]
Fig. 2.52: Phase diagram of silver-copper
[[File:Phase diagram of silver copper.jpg|right|thumb|Phase diagram of silver-copper]]
Fig. 2.53: Phase diagram of silver-cadmium
[[File:Phase diagram of silver cadmium.jpg|right|thumb|Phase diagram of silver-cadmium]]
Fig. 2.54: Strain hardening of AgCu3 by cold working
[[File:Strain hardening of AgCu3 by cold working.jpg|right|thumb|Strain hardening of AgCu3 by cold working]]
'''Table 2.14<figtable id="tab: Mechanical Contact and Switching Properties of Silver and Silver Alloys'''<table border="1" cellspacing="0" style="border-collapse:collapse"><tr><td><p class="s12">Material/</p><p class="s12">DODUCO-Designation</p></td><td><p class="s12">Hardness</p><p class="s12">Condition</p></td><td><p class="s12">Tensile Strength</p><p class="s12">R<span class="s31">m </span>[MPa]</p></td><td><p class="s12">Elongation A [%] min.</p></td><td><p class="s12">Vickers Hardness</p><p class="s12">HV 10</p></td></tr><tr><td><p class="s12">Ag</p></td><td><p class="s12">R 200</p><p class="s12">R 250</p><p class="s12">R 300</p><p class="s12">R 360</p></td><tdcaption>'''<p class="s12">200 !- 250</p><p class="s12">250 - 300</p><p class="s12">300 - 360</p><p class="s12">&gt; 360</p></td><td><p class="s12">30</p><p class="s12">8</p><p class="s12">3</p><p class="s12">Table 2</p></td><td><p class="s12">30</p><p class="s12">60</p><p class="s12">80</p><p class="s12">90</p></td></tr><tr><td><p class="s12">AgNi 0,.15</p><p class="s12">ARGODUR Special</p></td><td><p class="s12">R 220</p><p class="s12">R 270</p><p class="s12">R 320</p><p class="s12">R 360</p></td><td><p class="s12">220 :- 270</p><p class="s12">270 - 320</p><p class="s12">320 - 360</p><p class="s12">&gt; 360</p></td><td><p class="s12">25</p><p class="s12">6</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">40</p><p class="s12">70</p><p class="s12">85</p><p class="s12">100</p></td></tr><tr><td><p class="s12">AgCu3</p></td><td><p class="s12">R 250</p><p class="s12">R 330</p><p class="s12">R 400</p><p class="s12">R 470</p></td><td><p class="s12">250 - 330</p><p class="s12">330 - 400</p><p class="s12">400 - 470</p><p class="s12">&gt; 470</p></td><td><p class="s12">25</p><p class="s12">4</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">45</p><p class="s12">90</p><p class="s12">115</p><p class="s12">120</p></td></tr><tr><td><p class="s12">AgCu5</p></td><td><p class="s12">R 270</p><p class="s12">R 350</p><p class="s12">R 460</p><p class="s12">R 550</p></td><td><p class="s12">270 - 350</p><p class="s12">350 - 460</p><p class="s12">460 - 550</p><p class="s12">&gt; 550</p></td><td><p class="s12">20</p><p class="s12">4</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">55</p><p class="s12">90</p><p class="s12">115</p><p class="s12">135</p></td></tr><tr><td><p class="s12">AgCu10</p></td><td><p class="s12">R 280</p><p class="s12">R 370</p><p class="s12">R 470</p><p class="s12">R 570</p></td><td><p class="s12">280 - 370</p><p class="s12">370 - 470</p><p class="s12">470 - 570</p><p class="s12">&gt; 570</p></td><td><p class="s12">15</p><p class="s12">3</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">60</p><p class="s12">95</p><p class="s12">130</p><p class="s12">150</p></td></tr><tr><td><p class="s12">AgCu28</p></td><td><p class="s12">R 300</p><p class="s12">R 380</p><p class="s12">R 500</p><p class="s12">R 650</p></td><td><p class="s12">300 - 380</p><p class="s12">380 - 500</p><p class="s12">500 - 650</p><p class="s12">&gt; 650</p></td><td><p class="s12">10</p><p class="s12">3</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">90</p><p class="s12">120</p><p class="s12">140</p><p class="s12">160</p></td></tr><tr><td><p class="s12">Ag98CuNi</p><p class="s12">ARGODUR 27</p></td><td><p class="s12">R 250</p><p class="s12">R 310</p><p class="s12">R 400</p><p class="s12">R 450</p></td><td><p class="s12">250 - 310</p><p class="s12">310 - 400</p><p class="s12">400 - 450</p><p class="s12">&gt; 450</p></td><td><p class="s12">20</p><p class="s12">5</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">50</p><p class="s12">85</p><p class="s12">110</p><p class="s12">120</p></td></tr><tr><td><p class="s12">AgCu24,5Ni0,5</p></td><td><p class="s12">R 300</p><p class="s12">R 600</p></td><td><p class="s12">300 - 380</p><p class="s12">&gt; 600</p></td><td><p class="s12">10</p><p class="s12">1</p></td><td><p class="s12">105</p><p class="s12">180</p></td></tr><tr><td><p class="s12">AgCd10</p></td><td><p class="s12">R 200</p><p class="s12">R 280</p><p class="s12">R 400</p><p class="s12">R 450</p></td><td><p class="s12">200 - 280</p><p class="s12">280 - 400</p><p class="s12">400 - 450</p><p class="s12">&gt; 450</p></td><td><p class="s12">15</p><p class="s12">3</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">36</p><p class="s12">75</p><p class="s12">100</p><p class="s12">115</p></td></tr><tr><td><p class="s12">Ag99,5NiMg</p><p class="s12">ARGODUR 32</p><p class="s12">Not heat treated</p></td><td><p class="s12">R 220</p><p class="s12">R 260</p><p class="s12">R 310</p><p class="s12">R 360</p></td><td><p class="s12">220</p><p class="s12">260</p><p class="s12">310</p><p class="s12">360</p></td><td><p class="s12">25</p><p class="s12">5</p><p class="s12">2</p><p class="s12">1</p></td><td><p class="s12">40</p><p class="s12">70</p><p class="s12">85</p><p class="s12">100</p></td></tr><tr><td><p class="s12">ARGODUR 32 Heat treated</p></td><td><p class="s12">R 400</p></td><td><p class="s12">400</p></td><td><p class="s12">2</p></td><td><p class="s12">130-170</p></td></tr>Contact and Switching Properties of Silver and Silver Alloys'''</tablecaption>
Fig. 2.55: Softening of AgCu3 after annealing for 1 hr after 80% cold working[[File:Softening of AgCu3 after annealing.jpg|right|thumb{|Softening of AgCu3 after annealing for 1 hr after 80% cold working]]Fig. 2.56class="twocolortable" style="text-align: Strain hardening of AgCu5 by cold working[[Fileleft; font-size:Strain hardening of AgCu5 by cold working.jpg|right|thumb|Strain hardening of AgCu5 by cold working]]12px"Fig. 2.57: Softening of AgCu5 after annealing for 1 hr after 80% cold working[[File:Softening of AgCu5 after annealing.jpg|right|thumb|Softening of AgCu5 after annealing for 1 hr after 80% cold working]]-Fig. 2.58: Strain hardening of AgCu 10 by cold working[[File:Strain hardening of AgCu 10 by cold working.jpg|right|thumb|Strain hardening of AgCu 10 by cold working]]!Material Fig. !colspan="2.59: Softening of AgCu10 after annealing for 1 hr after 80% cold working[[File:Softening of AgCu10 after annealing.jpg" |right|thumb|Softening of AgCu10 after annealing for 1 hr after 80% cold working]]PropertiesFig. 2.60: Strain hardening of AgCu28 by cold working[[File:Strain hardening of AgCu28 by cold working.jpg|right|thumb|Strain hardening of AgCu28 by cold working]]Fig. 2.61: Softening of AgCu28 after annealing for 1 hr after 80% cold working-[[File:Softening of AgCu28 after annealing.jpg|right|thumb|Softening of AgCu28 after annealing for 1 hr after 80% cold working]]Fig. 2.62: Strain hardening of Ag<br />AgNi0.15 by cold working[[File:Strain hardening of AgNiO15 by cold working.jpg|rightHighest electrical and thermal conductivity, high affinity to sulfur (sulfide formation), low welding resistance, low contact resistance, very good formability |thumbOxidation resistant at higher make currents, limited arc erosion resistance, tendency to material transfer in DC circuits, easy to braze and weld to carrier materials|Strain hardening of AgNiO15 by cold working]]-Fig. 2.63: Softening of AgNi0.15 after annealing for 1 hr after 80% cold working|Ag Alloys [[File:Softening of AgNiO15 after annealing.jpg|rightIncreasing contact resistance with increasingCu content, compared to fine Ag higher arc erosion resistance and mechanical strength, lower tendency to material transfer|thumbGood formability, good brazing and welding properties |Softening of AgNiO15 after annealing]]}Fig. 2.64: Strain hardening of ARGODUR 27 by cold working</figtable>
Fig. 2.65: Softening of ARGODUR 27 after annealing for 1 hr after 80% cold working
<figtable id="tab:Application Examples and Forms of Supply for Silver and Silver Alloys"><caption>'''<!--Table 2.1516: Contact -->Application Examples and Switching Properties Forms of Supply for Silver and Silver Alloys'''</caption>
{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Application Examples!Form of Supply|-|Ag<br />AgNi0.15<br />AgCu3<br />AgNi98NiCu2<br />ARGODUR 27<br />AgCu24,5Ni0,5|Relays,<br />Micro switches,<br />Auxiliary current switches,<br />Control circuit devices,<br />Appliance switches,<br />Wiring devices (&le; 20A),<br />Main switches |'''Table 2.16Semi-finished Materials:''' <br />Strips, wires, contact profiles, clad contact strips, toplay profiles, seam- welded strips<br />'''Contact Parts: Application Examples '''<br />Contact tips, solid and Forms of Supply for Silver composite rivets, weld buttons; clad, welded and Silver Alloysriveted contact parts|-|AgCu5<br />AgCu10<br />AgCu28 |Special applications|'''Semi-finished Materials:'''<br />Strips, wires, contact profiles, clad contact strips, seam-welded strips<br />'''Contact parts:'''<br />Contact tips, solid contact rivets, weld buttons; clad, welded and riveted contact parts|-|Ag99.5NiOMgO<br />ARGODUR 32|Miniature relays, aerospace relays and contactors, erosion wire for injection nozzles|Contact springs, contact carrier parts |}</figtable>
====Silver-Palladium Alloys====
The addition of 30 wt% Pd increases the mechanical properties as well as theresistance of silver against the influence of sulfur and sulfur containingcompounds significantly ''(Tables <xr id="tab:Physical Properties of Silver-Palladium Alloys"/><!--(Tab 2.17 )--> and <xr id="tab:Mechanical Properties of Silver-Palladium Alloys"/>)<!--(Tab.2.18)''-->.Alloys with 40-60 wt% Pd have an even higher resistance against silver sulfideformation. At these percentage ranges however , the catalytic properties ofpalladium can influence the contact resistance behavior negatively. Theformability also decreases with increasing Pd contents. AgPd alloys are hard, arc erosion resistant, and have a lower tendency towards material transfer under DC loads (<xr id="tab:Contact and Switching Properties of Silver-Palladium Alloys"/>)<!--(Table 2.19)-->. On the other hand, the electrical conductivity is decreased at higher Pd contents. The ternary alloy AgPd30Cu5 has an even higher hardness, which makes it suitable for use in sliding contact systems. AgPd alloys are mostly used in relays for the switching of medium to higher loads (> 60V, > 2A) as shown in <xr id="tab:Application Examples and Forms of Suppl for Silver-Palladium Alloys"/><!--(Table 2.20)-->. Because of the high palladium price, these formerly solid contacts have been widely replaced by multi-layer designs such as AgNi0.15 or AgNi10 with a thin Au surface layer. A broader field of application for AgPd alloys remains in the wear resistant sliding contact systems.  <div class="multiple-images"><figure id="fig:Phase diagram of silver palladium">[[File:Phase diagram of silver palladium.jpg|left|thumb|<caption>Phase diagram of silver-palladium</caption>]]</figure> <figure id="fig:Strain hardening of AgPd30 by cold working">[[File:Strain hardening of AgPd30 by cold working.jpg|left|thumb|<caption>Strain hardening of AgPd30 by cold working</caption>]]</figure> <figure id="fig:Strain hardening of AgPd50 by cold working">[[File:Strain hardening of AgPd50 by cold working.jpg|left|thumb|<caption>Strain hardening of AgPd50 by cold working</caption>]]</figure>
AgPd alloys are hard, arc erosion resistant, and have a lower tendency towards<figure id="fig:Strain hardening of AgPd30Cu5 by cold working">material transfer under DC loads ''(Table 2.19)''[[File:Strain hardening of AgPd30Cu5 by cold working. On the other hand the electricalconductivity is decreased at higher Pd contents. The ternary alloy jpg|left|thumb|<caption>Strain hardening of AgPd30Cu5by cold working</caption>]]has an even higher hardness which makes it suitable for use in sliding contactsystems.</figure>
AgPd alloys are mostly used in relays for the switching <figure id="fig:Softening of medium to higher loadsAgPd30 AgPd50 AgPd30Cu5">([[File:Softening of AgPd30 AgPd50 AgPd30Cu5.jpg|left|thumb|<caption>60VSoftening of AgPd30, AgPd50, and AgPd30Cu5 after annealing of 1 hr after 80% cold working</caption>2A) as shown in Table 2.20. Because of the high palladium price these]]formerly solid contacts have been widely replaced by multi-layer designs such</figure>as AgNi0.15 or AgNi10 with a thin Au surface layer. A broader field of application</div>for AgPd alloys remains in the wear resistant sliding contact systems.<div class="clear"></div>
Fig. 2.66: Phase diagram of silver-palladium
Fig. 2.67<figtable id="tab:Strain hardeningPhysical Properties of AgPd30 by cold workingSilver-Palladium Alloys">
Fig. <caption>'''<!--Table 2.6817:Strain hardening--> Physical Properties of AgPd50 by cold workingSilver-Palladium Alloys'''</caption>
Fig{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Palladium Content<br />[wt%]!Density<br />[g/cm<sup>3</sup>]!Melting Point<br />or Range<br />[°C]!Electrical<br />Resistivity<br />[μΩ·cm]!Electrical<br />Conductivity<br />[MS/m]!Thermal<br />Conductivity<br />[W/m·K]!Temp. Coefficient of<br />the Electr. Resistance<br />[10<sup>-3</sup>/K]|-|AgPd30|30|10.9|1155 - 1220|14.7|6.8|60|0.4|-|AgPd40|40|11.1|1225 - 1285|20.8|4.8|46|0.36|-|AgPd50|50|11. 2|1290 - 1340|32.3|3.1|34|0.23|-|AgPd60|60|11.69:4|1330 - 1385|41.7|2.4|29|0.12Strain hardening|-of |AgPd30Cu5by cold working|30|10.8|1120 - 1165|15.6|6.4|28|0.37|}</figtable>
Fig. 2.70:
Softening of AgPd30, AgPd50,
and AgPd30Cu5 after annealing of 1 hr
after 80% cold working
<figtable id="tab:Mechanical Properties of Silver-Palladium Alloys"><caption>'''<!--Table 2.1718: Physical -->Mechanical Properties of Silver-Palladium Alloys'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p></th><th><p class="s12">Hardness</p><p class="s12">Condition</p></th><th><p class="s12">Tensile Strength</p><p class="s12">R<span class="s31"><sub>m</sub></span>[MPa]</p></th><th><p class="s12">Elongation A</p><p class="s12">[%]min.</p></th><th><p class="s12">Vickers Hardness</p><p class="s12">HV</p></th></tr><tr><td><p class="s12">AgPd30</p></td><td><p class="s12">R 320</p><p class="s12">R 570</p></td><td><p class="s12">320</p><p class="s12">570</p></td><td><p class="s12">38</p><p class="s12">3</p></td><td><p class="s12">65</p><p class="s12">145</p></td></tr><tr><td><p class="s12">AgPd40</p></td><td><p class="s12">R 350</p><p class="s12">R 630</p></td><td><p class="s12">350</p><p class="s12">630</p></td><td><p class="s12">38</p><p class="s12">2</p></td><td><p class="s12">72</p><p class="s12">165</p></td></tr><tr><td><p class="s12">AgPd50</p></td><td><p class="s12">R 340</p><p class="s12">R 630</p></td><td><p class="s12">340</p><p class="s12">630</p></td><td><p class="s12">35</p><p class="s12">2</p></td><td><p class="s12">78</p><p class="s12">185</p></td></tr><tr><td><p class="s12">AgPd60</p></td><td><p class="s12">R 430</p><p class="s12">R 700</p></td><td><p class="s12">430</p><p class="s12">700</p></td><td><p class="s12">30</p><p class="s12">2</p></td><td><p class="s12">85</p><p class="s12">195</p></td></tr><tr><td><p class="s12">AgPd30Cu5</p></td><td><p class="s12">R 410</p><p class="s12">R 620</p></td><td><p class="s12">410</p><p class="s12">620</p></td><td><p class="s12">40</p><p class="s12">2</p></td><td><p class="s12">90</p><p class="s12">190</p></td></tr></table></figtable>
Table 2.18: Mechanical Properties of Silver-Palladium Alloys
<figtable id="tab:Contact and Switching Properties of Silver-Palladium Alloys"><caption>'''<!--Table 2.19: -->Contact and Switching Properties of Silver-Palladium Alloys''</caption>'
{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !colspan="2" | Properties|-|AgPd30-60|Corrosion resistant, tendency to Brown Powder formation increases with Pd content, low tendency to material transfer in DC circuits, high ductility |Resistant against Ag<sub>2</sub>S formation, low contact resistance, increasing hardness with higher Pd content, AgPd30 has highest arc erosion resistance, easy to weld and clad|-|AgPd30Cu5 |High mechanical wear resistance|High Hardness |}</figtable>  <figtable id="tab:Application Examples and Forms of Suppl for Silver-Palladium Alloys"><caption>'''<!--Table 2.20: -->Application Examples and Forms of Suppl for Silver-Palladium Alloys'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p></th><th><p class="s12">Application Examples</p></th><th><p class="s12">Form of Supply</p></th></tr><tr><td><p class="s12">AgPd 30-60</p></td><td><p class="s12">Switches, relays, push-buttons,</p><p class="s12">connectors, sliding contacts</p></td><td><p class="s12">'''Semi-finished Materials:'''</p><p class="s12">Wires, micro profiles (weld tapes), clad</p><p class="s12">contact strips, seam-welded strips</p><p class="s12">'''Contact Parts:'''</p><p class="s12">Solid and composite rivets, weld buttons;</p><p class="s12">clad and welded contact parts, stamped parts</p></td></tr><tr><td><p class="s12">AgPd30Cu5</p></td><td><p class="s12">Sliding contacts, slider tracks</p></td><td><p class="s12">Wire-formed parts, contact springs, solid</p><p class="s12">and clad stamped parts</p></td></tr></table></figtable>
===Silver Composite Materials===
====Silver-Nickel (SINIDUR) Materials====Since silver and nickel are not soluble in each other in solid form and also show very limited solubility in the liquidphase have only very limited solubility , silver nickel composite materials withhigher Ni contents can only be produced by powder metallurgy. During extrusionof sintered Ag/Ni billets into wires, strips and rods , the Ni particles embedded inthe Ag matrix are stretched and oriented in the microstructure into a pronouncedfiber structure ''(Figs<xr id="fig:Micro structure of AgNi9010"/><!--(Fig. 2.75)--> and <xr id="fig:Micro structure of AgNi 8020"/>)<!--(Fig. and 2.76)''-->
The high density produced during hot extrusion , aids the arc erosion resistanceof these materials ''(Tables <xr id="tab:Physical Properties of Silver-Nickel (SINIDUR) Materials"/>)<!--(Tab 2.21 and 2.22)''-->. The typical application of Ag/Nicontact materials is in devices for switching currents of up to 100A ''(<xr id="tab:Application Examples and Forms of Supply for Silver-Nickel (SINIDUR) Materials"/>)<!--(Table 2.24)''-->.In this range , they are significantly more erosion resistant than silver or silveralloys. In addition , they exhibit with nickel contents <20 wt% a low and over theiroperational lifetime consistent contact resistance and good arc movingproperties. In DC applications Ag/Ni materials exhibit a relatively low tendencyof material transfer distributed evenly over the contact surfaces ''(<xr id="tab:Contact and Switching Properties of Silver-Nickel (SINIDUR) Materials"/>)<!--(Table 2.23)''-->.
Typically Ag/Ni (SINIDUR) materials are usually produced with contents of 10-40wt% Ni. The most widely common used materials SINIDUR Ag/Ni 10 and SINIDUR Ag/Ni 20- and alsoSINIDUR Ag/Ni 15, mostly used in north america-, are easily formable and applied bycladding ''(Figs<xr id="fig:Strain hardening of AgNi9010 by cold working"/>,<!--(Fig. 2.71)--> <xr id="fig:Softening of AgNi9010 after annealing"/>,<!--(Fig. 2.72)--> <xr id="fig:Strain hardening of AgNi8020"/>, <!--(Fig. 2.73)--> <xr id="fig:Softening of AgNi8020 after annealing"/>)<!--(Fig. 2.74)''-->. They can be, without any additional welding aids,economically welded and brazed to the commonly used contact carriermaterials.The (SINIDUR) Ag/Ni materials with nickel contents of 30 and 40 wt% are used inswitching devices , requiring a higher arc erosion resistance and where increasesin contact resistance can be compensated through higher contact forces.
The most important applications for Ag/Ni contact materials are typically inrelays, wiring devices, appliance switches, thermostatic controls, auxiliaryswitches, and small contactors with nominal currents >20A ''(<xr id="tab:Application Examples and Forms of Supply for Silver-Nickel (SINIDUR) Materials"/>)<!--(Table 2.24)''-->.
<figtable id="tab:Physical Properties of Silver-Nickel (SINIDUR) Materials"><caption>'''<!--Table 2.21: -->Physical Properties of Silver-Nickel Materials'''</caption><table class="twocolortable"><tr><th>Material</th><th>Silver Content</th><th>Density</th><th>Melting Point</th><th>ElectricalResistivity<i>p</i></th><th colspan="2">Electrical Resistivity (SINIDURsoft) Materials</th></tr><tr><th></th><th>[wt%]</th><th>[g/cm<sup>3</sup>]</th><th>[°C]</th><th>[µΩ·cm]</th><th>[% IACS]</th><th>[MS/m]</th></tr><tr><td><p class="s11">Ag/Ni 90/10</p><p class="s11"></p></td><td><p class="s11">89 - 91</p></td><td><p class="s11">10.2 - 10.3</p></td><td><p class="s11">960</p></td><td><p class="s11">1.82 - 1.92</p></td><td><p class="s12">90 - 95</p></td><td><p class="s12">52 - 55</p></td></tr><tr><td><p class="s11">Ag/Ni 85/15</p><p class="s11"></p></td><td><p class="s11">84 - 86</p></td><td><p class="s11">10.1 - 10.2</p></td><td><p class="s11">960</p></td><td><p class="s11">1.89 - 2.0</p></td><td><p class="s12">86 - 91</p></td><td><p class="s12">50 - 53</p></td></tr><tr><td><p class="s11">Ag/Ni 80/20</p><p class="s11"></p></td><td><p class="s11">79 - 81</p></td><td><p class="s11">10.0 - 10.1</p></td><td><p class="s11">960</p></td><td><p class="s11">1.92 - 2.08</p></td><td><p class="s12">83 - 90</p></td><td><p class="s12">48 - 52</p></td></tr><tr><td><p class="s11">Ag/Ni 70/30</p><p class="s11"></p></td><td><p class="s11">69 - 71</p></td><td><p class="s11">9.8</p></td><td><p class="s11">960</p></td><td><p class="s11">2.44</p></td><td><p class="s12">71</p></td><td><p class="s12">41</p></td></tr><tr><td><p class="s11">Ag/Ni 60/40</p><p class="s11"></p></td><td><p class="s11">59 - 61</p></td><td><p class="s11">9.7</p></td><td><p class="s11">960</p></td><td><p class="s11">2.70</p></td><td><p class="s12">64</p></td><td><p class="s12">37</p></td></tr></table></figtable>
Table 2.22: Mechanical Properties of Silver-Nickel (SINIDUR) Materials
Fig<figtable id="tab:tab2. 22"><caption>'''<!-- Table 2.7122:Strain hardening-->Mechanical Properties of Ag/Ni 90Silver-Nickel Materials'''</10 by cold workingcaption>
Fig{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Hardness Condition!Tensile Strength R<sub>m</sub> [Mpa]!Elongation A (soft annealed) [%] min. !Vickers Hardness HV 10|-|Ag/Ni 90/10<br />|soft<br />R 220<br />R 280<br />R 340<br />R 400|< 250<br />220 - 280<br />280 - 340<br />340 - 400<br />> 400|25<br />20<br />3<br />2.72:<br />1|< 50<br />50 - 70<br />65 - 90<br />85 - 105<br />> 100|-|Ag/Ni 85/15<br />|soft<br />R 300<br />R 350<br />R 380<br />R 400|< 275<br />250 - 300<br />300 - 350<br />350 - 400<br />> 400|20<br />4<br />2<br />2<br />1|< 70<br />70 - 90<br />85 - 105<br />100 - 120<br />> 115|-Softening of |Ag/Ni 80/20<br />|soft<br />R 300<br />R 350<br />R 400<br />R 450|< 300<br />300 - 350<br />350 - 400<br />400 - 450<br />> 450|20<br />4<br />2<br />2<br />1|< 80<br />80 - 95<br />90- 110<br />100 - 125<br />> 120|-|Ag/Ni 70/30<br />|R 330<br />R 420<br />R 470<br /10>R 530after annealing|330 - 420<br />420 - 470<br />470 - 530<br />> 530for |8<br />2<br />1 hr after <br />1|80% cold working<br />100<br />115<br />135|-|Ag/Ni 60/40<br />|R 370<br />R 440<br />R 500<br />R 580|370 - 440<br />440 - 500<br />500 - 580<br />> 580|6<br />2<br />1<br />1|90<br />110<br />130<br />150|}</figtable>
Fig. 2.73:
Strain hardening
of Ag/Ni 80/20 by cold working
Fig. 2.74<div class="multiple-images"><figure id="fig:Strain hardening of AgNi9010 by cold working">Softening [[File:Strain hardening of AgNi9010 by cold working.jpg|right|thumb|<caption>Strain hardening of Ag/Ni 8090/20after annealingfor 1 hr after 80% 10 by cold working</caption>]]</figure>
Fig<figure id="fig:Softening of AgNi9010 after annealing">[[File:Softening of AgNi9010 after annealing. 2.75: Micro structure jpg|right|thumb|<caption>Softening of Ag/Ni 90/10 a) perpendicular to the extrusion directionafter annealing for 1 hr after 80% cold working</caption>]]b) parallel to the extrusion direction</figure>
Fig<figure id="fig:Strain hardening of AgNi8020">[[File:Strain hardening of AgNi8020. 2.76: Micro structure jpg|right|thumb|<caption>Strain hardening of Ag/Ni 80/20 a) perpendicular to the extrusion directionby cold working</caption>]]b) parallel t o the extrusion direction</figure>
Table 2<figure id="fig:Softening of AgNi8020 after annealing">[[File:Softening of AgNi8020 after annealing.23: Contact and Switching Properties jpg|right|thumb|<caption>Softening of Silver-Nickel (SINIDUR) MaterialsAg/Ni 80/20 after annealing for 1 hr after 80% cold working</caption>]]</figure>
<figure id="fig:Micro structure of AgNi9010">[[File:Micro structure of AgNi9010.jpg|right|thumb|<caption>Micro structure of Ag/Ni 90/10 a) perpendicular to the extrusion direction b) parallel to the extrusion direction</caption>]]</figure> <figure id="fig:Micro structure of AgNi 8020">[[File:Micro structure of AgNi 8020.jpg|right|thumb|<caption>Micro structure of Ag/Ni 80/20 a) perpendicular to the extrusion direction b) parallel to the extrusion direction</caption>]]</figure></div><div class="clear"></div>  <figtable id="tab:Contact and Switching Properties of Silver-Nickel (SINIDUR) Materials"><caption>'''<!-- Table 2.2423:-->Contact and Switching Properties of Silver-Nickel Materials'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Properties|-|Ag/Ni <br />|High arc erosion resistance at switching currents up to 100A,<br />Resistance against welding for starting current up to 100A,<br />low and over the electrical contact life nearly constant contact resistance for Ag/Ni 90/10 and Ag/Ni 80/20,<br />ow and spread-out material transfer under DC load,<br />non-conductive erosion residue on isolating components resulting in only minor change of the dielectric strength of switching devices,<br />good arc moving properties,<br />good arc extinguishing properties,<br />good or sufficient ductility depending on the Ni content,<br />easy to weld and braze|}</figtable>  <figtable id="tab: Application Examples and Forms of Supplyfor Silver-Nickel (SINIDUR) Materials"><caption>'''<!--Table 2.24:-->Application Examples and Forms of Supply for Silver-Nickel Materials'''</caption> {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Application Examples!Switching or Nominal Current!Form of Supply|-|Ag/Ni 90/10-80/20|Relays<br /> Automotive Relays - Resistive load - Motor load|> 10A<br />> 10A|rowspan="9" | '''Semi-finisched Materials:'''<br />Wires, profiles,<br />clad strips,<br />Seam-welded strips,<br />Toplay strips <br />'''Contact Parts:'''<br />Contact tips, solid<br />and composite<br />rivets, Weld buttons,<br />clad, welded,<br />brazed, and riveted<br />contact parts|-|Ag/Ni 90/10, Ag/Ni 85/15-80/20|Auxiliary current switches|&le; 100A|-|Ag/Ni 90/10-80/20|Appliance switches|&le; 50A|-|Ag/Ni 90/10|Wiring devices|&le; 20A|-|Ag/Ni 90/10|Main switches, Automatic staircase illumination switches|&le; 100A|-|Ag/Ni 90/10-80/20|Control<br />Thermostats|> 10A<br />&le; 50A|-|Ag/Ni 90/10-80/20|Load switches|&le; 20A|-|Ag/Ni 90/10-80/20|Contactors circuit breakers|&le; 100A|-|Ag/Ni 90/10-80/20<br />paired with Ag/C 97/3-96/4|Motor protective circuit breakers|&le; 40A|-|Ag/Ni 80/20-60/40<br />paired with Ag/C 96/4-95/5|Fault current circuit breakers|&le; 100A|rowspan="2" | Rods, Profiles,<br />Contact tips, Formed parts,<br />brazed and welded<br />contact parts|-|Ag/Ni 80/20-60/40<br />paired with Ag/C 96/4-95/5|Power switches|> 100A|}</figtable>
==== Silver-Metal Oxide Materials Ag/CdO, Ag/SnO<sub>2</sub>, Ag/ZnO====
The family of silver-metal oxide contact materials includes the material groups:silver-cadmium oxide (DODURIT CdO), silver-tin oxide (SISTADOX), and silverzincoxide (DODURIT ZnO). Because of their very good contact and switchingproperties like high resistance against welding, low contact resistance, and higharc erosion resistance, silver-metal oxides have gained an outstanding positionin a broad field of applications. They are mainly are used in low voltage electricalswitching devices like relays, installation and distribution switches, appliances,industrial controls, motor controls, and protective devices ''(<xr id="tab:Application Examples of Silver–Metal Oxide Materials"/>)<!--(Table 2.1331)''-->.
*'''Silver-cadmium oxide (DODURIT CdO) materials'''
Silver-cadmium oxide (DODURIT CdO) materials with 10-15 wt% are producedby both, internal oxidation and powder metallurgical methods ''(Table 2.25)''.
The manufacturing of strips and wires by internal oxidation starts with a moltenalloy of silver and cadmium. During a heat treatment below it's melting point in aan oxygen rich atmosphere in of such a homogeneous alloy , the oxygen diffuses fromthe surface into the bulk of the material and oxidizes the Cd to CdO in a more orless fine particle precipitation inside the Ag matrix. The CdO particles are ratherfine in the surface area and are becoming getting larger further away towards the centerof the material ''(<xr id="fig:Micro structure of AgCdO9010"/>)<!--(Fig. 2.83)''-->.
During the manufacturing of Ag/CdO contact material by internal oxidation , theprocesses vary depending on the type of semi-finished material.For Ag/CdO wires , a complete oxidation of the AgCd wire is performed, followedby wire-drawing to the required diameter ''(<xr id="fig:Strain hardening of internally oxidized AgCdO9010"/><!--(Figs. 2.77 )--> and <xr id="fig:Softening of internally oxidized AgCdO9010"/>)<!--(Fig. 2.78)''-->. The resultingmaterial is used for example , in the production of contact rivets. For Ag/CdO stripmaterials two processes are commonly used: Cladding of an AgCd alloy stripwith fine silver , followed by complete oxidation , results in a strip material with asmall depletion area in the center of it's thickness and a an Ag backing suitable foreasy attachment by brazing (sometimes called “Conventional "Conventional Ag/CdO”CdO"). Usinga technology that allows the partial oxidation of a dual-strip AgCd alloy materialin a higher pressure pure oxygen atmosphere , yields a composite Ag/CdO stripmaterial that has - besides a relatively fine CdO precipitation - also a an easily brazableAgCd alloy backing ''(Fig. 2.85)''. These materials (DODURIT CdO ZH) are mainlyused as the basis for contact profiles and contact tips.
During powder metallurgical production , the powder mixed made by differentprocesses are typically converted by pressing, sintering and extrusion to wiresand strips. The high degree of deformation during hot extrusion , produces auniform and fine dispersion of CdO particles in the Ag matrix while at the sametime achieving a high density which is advantageous for good contact properties''(<xr id="fig:Micro structure of AgCdO9010P"/>)<!--(Fig. 2.84)''-->. To obtain a backing suitable for brazing, a fine silver layer is appliedby either com-pound extrusion or hot cladding prior to or right after the extrusion''(Fig. 2.86)''.
For larger contact tips, and especially those with a rounded shape, the single tipPress-Sinter-Repress process (PSR) offers economical advantages. Thepowder mix is pressed in into a die close to the final desired shape, the “green” "green" tipsare sintered, and in most cases , the repress process forms the exact final exact shapewhile at the same time , increasing the contact density and hardness.
Using different silver powders and minor additives for the basic Ag and CdO, starting materials can help influence certain contact properties for specializedapplications.
Fig. 2.77<div class="multiple-images"><figure id="fig:Strain hardening of internally oxidized AgCdO9010">[[File:Strain hardening of internally oxidized AgCdO9010.jpg|left|thumb|<caption>Strain hardening of internally oxidizedAg/CdO 90/10 by cold working</caption>]]</figure>
Fig. 2.78<figure id="fig:Softening of internally oxidized AgCdO9010">[[File:Softening of internally oxidizedAgCdO9010.jpg|left|thumb|<caption>Softening of internally oxidized (i.o.) Ag/CdO 90/10 after annealingfor 1 hr after 40% cold working</caption>]]</figure>
Table 2.25<figure id="fig: Physical and Mechanical Properties as well as Manufacturing Processes andStrain hardening of AgCdO9010P">Forms [[File:Strain hardening of Supply AgCdO9010P.jpg|left|thumb|<caption>Strain hardening of Extruded Silver Cadmium Oxidepowder metallurgical (DODURIT p.m.) Ag/CdO) Contact Materials90/10 by cold working</caption>]]</figure>
Fig. 2.79<figure id="fig:Softening of AgCdO9010P after annealing">Strain hardening [[File:Softening of AgCdO9010P after annealing.jpg|left|thumb|<caption>Softening ofpowder metallurgical Ag/CdO 90/10 P by after annealing for 1 hr after 40% cold working</caption>]]</figure>
Fig. 2.80<figure id="fig: SofteningStrain hardening of AgCdO8812">[[File:Strain hardening of AgCdO8812.jpg|left|thumb|<caption>Strain hardening of powder metallurgical Ag/CdO 9088/12</10 P after annealingcaption>]]for 1 hr after 40% cold working</figure>
Fig. 2.81<figure id="fig:Softening of AgCdO8812WP after annealing">Strain hardening[[File:Softening of AgCdO8812WP after annealing.jpg|left|thumb|<caption>Softening of powder metallurgical Ag/CdO 88/12 WPafter annealing for 1 hr after different degrees of cold working</caption>]]</figure>
Fig. 2.82<figure id="fig:Micro structure of AgCdO9010">Softening [[File:Micro structure of AgCdO9010.jpg|left|thumb|<caption>Micro structure of Ag/CdO 8890/10 i.o. a) close to surface b) in center area</12WP after annealingcaption>]]for 1 hr after different degrees ofcold working</figure>
Fig<figure id="fig:Micro structure of AgCdO9010P">[[File:Micro structure of AgCdO9010P. 2.83: jpg|left|thumb|<caption>Micro structure of Ag/CdO 90/10 ip.om. : a) close perpendicular to surfaceextrusion direction b) in center areaparallel to extrusion direction</caption>]]</figure>
Fig. 2.84: Micro structure of Ag</CdO 90div><div class="clear"></10 P:a) perpendicular to extrusion directionb) parallel to extrusion directiondiv>
Fig. 2.85:
Micro structure of Ag/CdO 90/10 ZH:
1) Ag/CdO layer
2) AgCd backing layer
Fig*'''Silver–tin oxide materials'''Over the past years, many Ag/CdO contact materials have been replaced by Ag/SnO<sub>2</sub> based materials with 2-14 wt% SnO<sub>2</sub> because of the toxicity of Cadmium. This changeover was further favored by the fact that Ag/SnO<sub>2</sub> contacts quite often show improved contact and switching properties such as lower arc erosion, higher weld resistance and a significant lower tendency towards material transfer in DC switching circuits (<xr id="tab:Contact and Switching Properties of Silver–Metal Oxide Materials"/>)<!--(Table 2.30)-->.86Ag/SnO<sub>2</sub> materials have been optimized for a broad range of applications by other metal oxide additives and modification in the manufacturing processes that result in different metallurgical, physical and electrical properties (<xr id="tab: Micro structure of AgCdO 88tab2.28"/12 WP><!--(Tab. 2.28)--> and <xr id="tab: atab2.29"/>) perpendicular to extrusion directionb<!--(Table 2.29) parallel to extrusion direction-->.
*Silver–tin oxide(SISTADOX)materialsOver the past years, many Ag/CdO contact materials have been replaced byManufacturing of Ag/SnO<sub>2</sub> based materials with 2-14 by ''internal oxidation'' is possible in principle, but during heat treatment of alloys containing > 5 wt% SnO<sub>2</sub> because of tin in oxygen, dense oxide layers formed on the surface of the material prohibit the further diffusion of oxygen into the toxicity bulk ofCadmiumthe material. This changeover was further favored by By adding Indium or Bismuth to the alloy, the fact internal oxidation is possible and results in materials that Ag/SnO<sub>2</sub>contacts quite often typically are rather hard and brittle and may show improved somewhat elevated contact resistance and switching properties is limited to applications in relays. Adding a brazable fine silver layer to such materials results in a semifinished material, suitable for the manufacture aslower arc erosion, higher smaller weld resistance, and a significant lower tendencytowards material transfer in DC switching circuits ''profiles (Table 2.30)''. <xr id="fig:Micro structure of AgSnO2 92 8 WTOS F"/SnO>)<sub>!--(Fig. 2</sub.116)-->. Because of their resistance to material transfer and low arc erosion, these materials have been optimized find for example a broad range broader application in automotive relays (<xr id="tab:Application Examples of applications by other metaloxide additives and modification in the manufacturing processes that result indifferent metallurgical, physical and electrical properties ''Silver–Metal Oxide Materials"/>)<!--(Table 2.2931)''-->.
Manufacturing ''Powder metallurgy'' plays a significant role in the manufacturing of Ag/SnO<sub>2</sub> by ''internal oxidation'' is possible in principle, butduring heat treatment of alloys containing contact materials. Besides SnO<sub>2</sub> 5 a smaller amount (<1 wt% ) of tin in oxygenone or more other metal oxides such as WO<sub>3</sub>, MoO<sub>3</sub>, dense oxideCuO and/or Bi<sub>2</sub>O<sub>3</sub> are added. Theselayers formed on additives improve the surface wettability of the material prohibit oxide particles and increase the further diffusion viscosity ofoxygen into the bulk of the materialAg melt. By adding Indium or Bismuth They also provide additional benefits to the alloy theinternal oxidation is possible mechanical and results in materials that typically are rather hardand brittle and may show somewhat elevated arcing contact resistance and is limitedto applications in relays. To make a ductile material with fine oxide dispersion(SISTADOX TOS F) ''(Fig. 2.114)'' it is necessary to use special process variationsin oxidation and extrusion which lead to materials with improved properties inrelays. Adding a brazable fine silver layer to such of materials results in a semifinishedmaterial suitable for the manufacture as smaller weld profilesthis group (SISTADOX WTOS F) ''(Fig<xr id="tab:tab2. 2.11626"/>)''. Because of their resistance to materialtransfer and low arc erosion these materials find for example a broaderapplication in automotive relays ''<!--(Table 2.3126)''-->.
''Powder metallurgy'' plays a significant role in the manufacturing of Ag/SnO<sub>2</sub>contact materialsfigtable id="tab:tab2. Besides SnO<sub>2</sub26"> a smaller amount (<1 wt%) of one or moreother metal oxides such as WO<subcaption>3'''</sub>, MoO<sub>3</sub!--Table 2.26:-->, CuO Physical and/or Bi<sub>2</sub>O<sub>3</sub> are added. Theseadditives improve the wettability of the oxide particles Mechanical Properties as well as Manufacturing Processes and increase the viscosityForms of the Ag melt. They also provide additional benefits to the mechanical andarcing contact properties Supply of materials in this group 'Extruded Silver-Tin Oxide Contact Materials'(Table 2.26)''.</caption>
In the manufacture the initial powder mixes different processes are applied{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Silver Content<br />[wt%]!Additives!Theoretical<br />Density<br />[g/cm<sup>3</sup>]!Electrical<br />Conductivity<br />[MS/m]!Vickers<br />Hardness<br />[HV0,1]which provide specific advantages of the resulting materials in respect to their!Tensile<br />Strength<br />[MPa]contact properties ''!Elongation (Figssoft annealed)<br />A[%]min. !Manufacturing<br />Process!Form of Supply|-|Ag/SnO<sub>2</sub> 98/2 SPW|97 - 99|WO<sub>3</sub>|10,4|59 ± 2|57 ± 15|215|35|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 92/8 SPW|91 - 93|WO<sub>3</sub>|10,1|51 ± 2|62 ± 15|255|25|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 90/10 SPW|89 - 91|WO<sub>3</sub>|10|47 ± 5||250|25|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 88/12 SPW|87 - 89|WO<sub>3</sub>|9.9|46 ± 5|67 ± 15|270|20|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 92/8 SPW4|91 - 93|WO<sub>3</sub>|10,1|51 ± 2|62 ± 15|255|25|Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 90/10 SPW4|89 - 91|WO<sub>3</sub>|10|||||Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 88/12 SPW4<br />|87 - 89|WO<sub>3</sub>|9,8|46 ± 5|80 ± 10|||Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 88/12 SPW6|87 - 89|MoO<sub>3</sub>|9.119)''8|42 ± 5|70 ± 10|||Powder Metallurgy|2|-|Ag/SnO<sub>2</sub> 97/3 SPW7|96 - 98|Bi<sub>2</sub>O<sub>3</sub> and WO<sub>3</sub>||||||Powder Metallurgy|2|-|Ag/SnO<sub>2</sub> 90/10 SPW7|89 - 91|Bi<sub>2</sub>O<sub>3</sub> and WO<sub>3</sub>|9,9|||||Powder Metallurgy|2|-|Ag/SnO<sub>2</sub> 88/12 SPW7|87 - 89|Bi<sub>2</sub>O<sub>3</sub> and WO<sub>3</sub>|9. Some of them are described here as8|42 ± 5|70 ± 10|||Powder Metallurgy|2|-|Ag/SnO<sub>2</sub> 98/2 PMT1|97 - 99|Bi<sub>2</sub>O<sub>3</sub> and CuO|10,4|57 ± 2||215|35|Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 96/4 PMT1|95 - 97|Bi<sub>2</sub>O<sub>3</sub> and CuO||||||Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 94/6 PMT1|93 - 95|Bi<sub>2</sub>O<sub>3</sub> and CuO||||||Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 92/8 PMT1|91 - 93|Bi<sub>2</sub>O<sub>3</sub> and CuO|10|50 ± 2|62 ± 15|240|25|Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 90/10 PMT1|89 - 91|Bi<sub>2</sub>O<sub>3</sub> and CuO|10|48 ± 2|65 ± 15|240|25|Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 88/12 PMT1|87 - 89|Bi<sub>2</sub>O<sub>3</sub> and CuO|9,9|46 ± 5||260|20|Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 90/10 PE|89 - 91|Bi<sub>2</sub>O<sub>3</sub> and CuO|9,8|48 ± 2|55 - 100|230 - 330|28|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 88/12 PE|87 - 89|Bi<sub>2</sub>O<sub>3</sub> and CuO|9,7|46 ± 5|60 - 106|235 - 330|25|Powder Metallurgy|1|-|Ag/SnO<sub>2</sub> 88/12 PMT2|87 - 89|CuO|9,9||90 ± 10|||Powder Metallurgy|1,2|-|Ag/SnO<sub>2</sub> 86/14 PMT3|85 - 87|Bi<sub>2</sub>O<sub>3</sub> and CuO|9,8||95 ± 10|||Powder Metallurgy|2|-|Ag/SnO<sub>2</sub> 94/6 LC1|93 - 95|Bi<sub>2</sub>O<sub>3</sub> and In<sub>2</sub>O<sub>3</sub>|9,8|45 ± 5|55 ± 10|follows:|:'''a) |Powder blending from single component powders''' Metallurgy|2|-|Ag/SnO<sub>2</sub> 90/10 POX1|89 - 91|In<sub>2</sub>O<sub>3</sub>|9,9|50 ± 5|85 ± 15|310|25|Internal Oxidation|1,2|-|Ag/SnO<sub>2</sub> 90/10 POX1|87 - 89|In<sub>2</sub>O<sub>3</sub>|9,8|48 ± 5|90 ± 15|325|25|Internal Oxidation|1,2|-|Ag/SnO<brsub>2</sub> 90/10 POX1|85 - 87 |In this common process all components including additives that are part of the powder mix are blended as single powders. The blending is usually performed in the dry stage in blenders of different design.<sub>2</sub>O<sub>3</sub>|9,6|45 ± 5|95 ± 15|330|20|Internal Oxidation|1,2|-|}</figtable>
:'''b) Powder blending on the basis of doped powders''' <br> For incorporation of additive oxides in the SnO<sub>1 = Wires, Rods, Contact rivets, 2</sub> powder the reactive spray process (RSV) has shown advantages. This process starts with a waterbased solution of the tin and other metal compounds. This solution is nebulized under high pressure and temperature in a reactor chamber. Through the rapid evaporation of the water each small droplet is converted into a salt crystal and from there by oxidation into a tin oxide particle in which the additive metals are distributed evenly as oxides. The so created doped AgSnO2 powder is then mechanically mixed with silver powder.= Strips, Profiles, Contact tips
:'''c) Powder blending based on coated oxide powders''' <br> In this process tin oxide powder is blended with lower meting additive oxides such as for example Ag<sub>2</sub> MoO<sub>4</sub> and then heat treated. The SnO<sub>2</sub> particles are coated in this step with a thin layer of the additive oxide.
In the manufacture for the initial powder mixes, different processes are applied which provide specific advantages of the resulting materials in respect to their contact properties <!--[[#figures|(Figs. 43 – 75)]]-->. Some of them are described here as follows::'''da) Powder blending based on internally oxidized alloy from single component powders''' <br> A combination of powder metallurgy and internal oxidation In this common process starts with atomized Ag alloy all components, including additives that are part of the powder which mix, are blended as single powders. The blending is subsequently oxidized usually performed in pure oxygen. During this process the Sn and other metal components are transformed to metal oxide and precipitated inside the silver matrix dry stage in blenders of each powder particledifferent design.
:'''eb) Powder blending based on chemically precipitated compound the basis of doped powders''' <br> A silver salt solution is added to a suspension For incorporation of for example additive oxides in the SnO<sub>2</sub> together powder, the reactive spray process has shown advantages. This process starts with a precipitation agentwaterbased solution of the tin and other metal compounds. This solution is nebulized under high pressure and temperature in a reactor chamber. In Through the rapid evaporation of the water, each small droplet is converted into a chemical reaction silver salt crystal and silver from there gets transformed by oxidation into a tin oxide respectively are precipitated around particle in which the additive metal oxide particles who act metals are distributed evenly as crystallization sitesoxides. Further chemical treatment then reduces the silver oxide with the resulting precipitated powder being a mix of Ag and SnOThe so created doped AgSnO<sub>2</sub>powder is then mechanically mixed with silver powder.
Further processing of these differently produced :'''c) Powder blending based on coated oxide powders follows theconventional processes of pressing''' <br> In this process, sintering and hot extrusion to wires andstrips. From these contact parts tin oxide powder is blended with lower melting additive oxides such as contact rivets and tips aremanufactured. To obtain a brazable backing the same processes as used forexample Ag<sub>2</CdO are appliedsub> MoO<sub>4</sub> and then heat treated. As for AgThe SnO<sub>2</CdO, larger contact tips can also bemanufactured more economically using sub> particles are coated in this step with a thin layer of the press-sinter-repress (PSR) process''(Table 2additive oxide.27).''
Fig. 2.87:Strain hardening '''d) Powder blending based on internally oxidized alloy powders''' <br> A combination ofpowder metallurgy and internal oxidation this process starts with atomized Ag/SnO<sub>2</sub> 92/8 PE by cold workingalloy powder which is subsequently oxidized in pure oxygen. During this process the Sn and other metal components are transformed to metal oxide and precipitated inside the silver matrix of each powder particle.
Fig:'''e) Powder blending based on chemically precipitated compound powders''' <br> A silver salt solution is added to a suspension of for example SnO<sub>2</sub> together with a precipitation agent. 2In a chemical reaction, silver and silver oxide respectively are precipitated around the additive metal oxide particles, who act as crystallization sites.88:Softening Further chemical treatment then reduces the silver oxide with the resulting precipitated powder, being a mix ofAg/and SnO<sub>2</sub> 92/8 PE after annealingfor 1 hr after 40% cold working.
Table 2Further processing of these differently produced powders follows the conventional processes of pressing, sintering and hot extrusion to wires and strips. From these contact parts, contact rivets and tips are manufactured. To obtain a brazable backing, the same processes as used for Ag/CdO are applied.26As for Ag/CdO, larger contact tips can also be manufactured using the press-sinter-repress (PSR) process (<xr id="tab: Physical and Mechanical Properties as well as Manufacturing Processes andForms of Supply of Extruded Powder Metallurgical Silver-Tin Metal Oxide Materials with Fine Silver Backing Produced by the Press-Sinter-Repress Process"/>)<!--(SISTADOXTable 2.27) Contact Materials-->.<div id="figures">
Fig. 2.89<div class="multiple-images"><figure id="fig:Strain hardening of AgSNO2 92 8 PE">[[File:Strain hardening of AgSNO2 92 8 PE.jpg|left|thumb|<caption>Strain hardening ofAg/SnO<sub>2</sub> 8892/12 8 PE by cold working</caption>]]</figure>
Fig. 2.90<figure id="fig:Softening of AgSnO2 92 8 PE"> [[File:Softening of AgSnO2 92 8 PE.jpg|left|thumb|<caption>Softening of Ag/SnO<sub>2</sub> 8892/12 8 PEafter annealing for1 hr after 40% cold working</caption>]]</figure>
Fig. 2.91<figure id="fig:Strain hardening of Ag SnO2 88 12 PE"> [[File:Strain hardening of Ag SnO2 88 12 PE.jpg|left|thumb|<caption>Strain hardening of oxidizedAg/SnO<sub>2</sub> 88/12 PW4 PE by cold working</caption>]]</figure>
Fig. 2.92<figure id="fig:Softening of Ag SnO2 88 12 PE after annealing"> [[File:Softening of Ag SnO2 88 12 PE after annealing.jpg|left|thumb|<caption>Softening of Ag/SnO<sub>2</sub> 88/12 PW4 PE afterannealing for 1 hrafter 3040% cold working</caption>]]</figure>
Fig. 2.93<figure id="fig:Strain hardening of oxidized AgSnO2 88 12 PW4"> [[File:Strain hardening ofoxidized AgSnO2 88 12 PW4.jpg|left|thumb|<caption>Strain hardening of oxidized Ag/SnO<sub>2</sub> 9888/2 PX12 PW4 by cold working</caption>]]</figure>
Fig. 2.94<figure id="fig:Softening of Ag SnO2 88 12 PW4 after annealing"> [[File:Softening of Ag SnO2 88 12 PW4 after annealing.jpg|left|thumb|<caption>Softening ofAg/SnO<sub>2</sub> 9888/2 PX12 PW4 after annealingfor 1 hr after 8030%cold working</caption>]]</figure>
Fig 2.95<figure id="fig:Strain hardening of internally oxidized Ag SnO2 88 12 TOS F"> [[File:Strain hardening of internally oxidized Ag SnO2 88 12 TOS F.jpg|left|thumb|<caption>Strain hardeningof internally oxidized Ag/SnO<sub>2</sub> 9288/8 PX12 TOS F by cold working</caption>]]</figure>
Fig. 2.96<figure id="fig:Softening of Ag SnO2 88 12 TOS F after annealing"> [[File:Softening of Ag SnO2 88 12 TOS F after annealing.jpg|left|thumb|<caption>Softening ofAg/SnO<sub>2</sub> 9288/8 PX12 TOS F after annealing for 1 hrafter 4030% cold working</caption>]]</figure>
Fig. 2.97<figure id="fig:Strain hardening of internally oxidized Ag SnO2 88 12P"> [[File:Strain hardening of internally oxidized Ag SnO2 88 12P.jpg|left|thumb|<caption>Strain hardening of internallyoxidizedAg/SnO<sub>2</sub> 88/12 TOS F12P by cold working</caption>]]</figure>
Fig. 2.98<figure id="fig:Softening of Ag SnO2 88 12P after annealing"> [[File:Softening of Ag SnO2 88 12P after annealing.jpg|left|thumb|<caption>Softening ofAg/SnO<sub>2</sub> 88/12 TOS F SP afterannealing for 1 hr after 3040%cold working</caption>]]</figure>
Fig. 2.99<figure id="fig:Strain hardening of Ag SnO2 88 12 WPD"> [[File:Strain hardening of Ag SnO2 88 12 WPD.jpg|left|thumb|<caption>Strain hardening ofinternally oxidizedAg/SnO<sub>2</sub> 88/12P12 WPD by cold working</caption>]]</figure>
Fig. 2.100<figure id="fig:Softening of Ag SnO2 88 12 WPD after annealing"> [[File:Softening of Ag SnO2 88 12 WPD after annealing.jpg|left|thumb|<caption>Softening ofAg/SnO<sub>2</sub> 88/12P12 WPD after annealing for 1 hr after40% different degrees of cold working</caption>]]</figure>
Fig. 2.101<figure id="fig:Micro structure of Ag SnO2 92 8 PE"> Strain hardening [[File:Micro structure of Ag SnO2 92 8 PE.jpg|left|thumb|<caption>Micro structure ofAg/SnO<sub>2</sub> 8892/8 PE: a) perpendicular to extrusion direction b) parallel to extrusion direction</12 WPCcaption>]]by cold working</figure>
Fig. 2.102<figure id="fig:Micro structure of Ag SnO2 88 12 PE"> Softening [[File:Micro structure of Ag SnO2 88 12 PE.jpg|left|thumb|<caption>Micro structure of Ag/SnO<sub>2</sub> 88/12 WPC after annealingPE: a) perpendicular to extrusion direction b) parallel to extrusion direction</caption>]]for 1 hr after different degrees of cold working</figure>
Fig. 2.103<figure id="fig:Micro structure of Ag SnO2 88 12 PW"> Strain hardening [[File:Micro structure of Ag SnO2 88 12 PW.jpg|left|thumb|<caption>Micro structure ofAg/SnO<sub>2</sub> 8688/12 SPW: a) perpendicular to extrusion direction b) parallel to extrusion direction</14 WPCcaption>]]by cold working</figure>
Fig. 2.104<figure id="fig:Micro structure of Ag SnO2 88 12 TOS F"> Softening [[File:Micro structure of Ag SnO2 88 12 TOS F.jpg|left|thumb|<caption>Micro structure of Ag/SnO<sub>2</sub> 8688/12 TOS F: a) perpendicular to extrusion direction b) parallel to extrusion direction</14 WPC after annealingcaption>]]for 1 hr after different degrees of cold working</figure>
Fig. 2.105<figure id="fig:Micro structure of Ag SnO2 92 8 WTOS F"> Strain hardening [[File:Micro structure of Ag SnO2 92 8 WTOS F.jpg|left|thumb|<caption>Micro structure ofAg/SnO<sub>2</sub> 8892/12 WPD8 WTOS F: a) perpendicular to extrusion direction b) parallel to extrusion direction,1) AgSnO2 contact layer, 2) Ag backing layer</caption>]]by cold working</figure>
Fig. 2.106<figure id="fig:Micro structure of Ag SnO2 88 12 WPD"> Softening [[File:Micro structure of Ag SnO2 88 12 WPD.jpg|left|thumb|<caption>Micro structure of Ag/SnO<sub>2</sub> 88/12 WPD afterannealing for : parallel to extrusion direction 1 hr after different degrees) AgSnO2 contact layer, 2) Ag backing layer</caption>]]of cold working</figure>
Fig. 2.108:Softening of Ag/SnO<subdiv class="clear">2</subdiv> 88/12 WPX afterannealing for 1 hr after different degreesof cold working
Fig. 2.107:
Strain hardening of
Ag/SnO<sub>2</sub> 88/12 WPX
by cold working
Fig. <figtable id="tab:Physical Properties of Powder Metallurgical Silver-Metal Oxide Materials with Fine Silver Backing Produced by the Press-Sinter-Repress Process"><caption>'''<!--Table 2.10927: Micro structure -->Physical Properties of AgPowder Metallurgical Silver-Metal Oxide Materials with Fine Silver Backing Produced by the Press-Sinter-Repress Process'''</caption><table class="twocolortable"><tr><th rowspan="2"><p class="s11">Material</p><p class="s11"></p></th><th rowspan="2"><p class="s11">Additives</p></th><th rowspan="2"><p class="s11">Density</p><p class="s11">[ g/cm<sup>3</sup>]</p></th><th rowspan="2"><p class="s11">Electrical</p><p class="s11">Resistivity</p><p class="s11">[µ<span class="s14">S ·</span>cm]</p></th><th colspan="2"><p class="s11">Electrical</p><p class="s11">Conductivity</p></th><th rowspan="2"><p class="s11">Vickers</p><p class="s11">Hardness</p><p class="s11">HV 10.</p></th></tr><tr><th><p class="s11">[%IACS]</p></th><th><p>[MS/m]</p></th></tr><tr><td><p class="s11">AgCdO 90/10</p><p class="s11"></p></td><td/><td><p class="s11">10.1</p></td><td><p class="s11">2.08</p></td><td><p class="s12">83</p></td><td><p class="s12">48</p></td><td><p class="s11">60</p></td></tr><tr><td><p class="s11">AgCdO 85/15 </p></td><td/><td><p class="s11">9.9</p></td><td><p class="s11">2.27</p></td><td><p class="s12">76</p></td><td><p class="s12">44</p></SnOtd><td><p class="s11">65</p></td></tr><tr><td><p class="s11">AgSnO<sub>2</sub> 9290/10</p></td><td><p class="s11">CuO and</p><p class="s11">Bi<sub>2</sub> O<sub>3</sub></p></td><td><p class="s11">9.8 PE</p></td><td><p class="s11">2.22</p></td><td><p class="s12">78</p></td><td><p class="s12">45</p></td><td><p class="s11">55</p></td></tr><tr><td><p class="s11">AgSnO<sub>2</sub> 88/12</p></td><td><p class="s11">CuO and</p><p class="s11">Bi<sub>2</sub> O<sub>3</sub></p></td><td><p class="s11">9.6</p></td><td><p class="s11">2.63</p></td><td><p class="s12">66</p></td><td><p class="s12">38</p></td><td><p class="s11">60</p></td></tr></table>Form of Support: a) perpendicular to extrusion directionformed parts, stamped parts, contact tipsb) parallel to extrusion direction</figtable>
Fig*'''Silver–zinc oxide materials'''Silver zinc oxide contact materials with mostly 6 - 10 wt% oxide content, including other small metal oxides, are produced exclusively by powder metallurgy [[#figures1|(Figs. 58 – 63)]]<!--(Table 2.110: Micro structure of 28)-->. Adding WO<sub>3</sub> or Ag<sub>2</sub>WO<sub>4</sub> in the process - as described in the preceding chapter on Ag/SnO<sub>2</sub> 88- has proven most effective for applications in AC relays, wiring devices, and appliance controls. Just like with the other Ag metal oxide materials, semi-finished materials in strip and wire form are used to manufacture contact tips and rivets. Because of their high resistance against welding and arc erosion Ag/12 PEZnO materials present an economic alternative to Cd free Ag-tin oxide contact materials (<xr id="tab: aContact and Switching Properties of Silver–Metal Oxide Materials"/><!--(Tab. 2.30) perpendicular to extrusion directionb--> and <xr id="tab:Application Examples of Silver–Metal Oxide Materials"/>)<!--(Tab. 2.31) parallel to extrusion direction-->.
Fig. 2.111: Micro structure of Ag/SnO<sub>2</sub> 88/12 PW: a) perpendicular to extrusion direction
b) parallel to extrusion direction
Fig<figtable id="tab:tab2. 28"><caption>'''<!--Table 2.11228: Micro structure --> Physical and Mechanical Properties as well as Manufacturing Processes and Forms of Ag/SnO<sub>2Supply of Extruded Silver-Zinc Oxide Contact'''</subcaption> 98/2 PX: a) perpendicular to extrusion directionb) parallel to extrusion direction
Fig{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Silver Content<br />[wt%]!Additives!Density<br />[g/cm<sup>3</sup>]!Electrical<br />Resistivity<br />[μΩ·cm]!colspan="2" style="text-align:center"|Electrical<br />Conductivity<br />[% IACS] [MS/m]!Vickers<br />Hardness<br />Hv1!Tensile<br />Strength<br />[MPa]!Elongation<br />(soft annealed)<br />A[%]min. !Manufacturing<br />Process!Form of<br />Supply|-|Ag/ZnO 92/8P<br />|91 - 93||9.8|2.22|78|45|60 - 95|220 - 350|25|Powder Metallurgy<br />a) indiv. powders|1|-|Ag/ZnO 92/8PW25<br />|91 - 93|Ag<sub>2</sub>WO<sub>4</sub>|9.6|2.113: Micro structure of 08|83|48|65 - 105|230 - 340|25|Powder Metallurgy<br />c) coated|1|-|Ag/SnOZnO 90/10PW25<br />|89 - 91|Ag<sub>2</sub> WO<sub>4</sub>|9.6|2.17|79|46|65 - 100|230 - 350|20|Powder Metallurgy<br />c) coated|1|-|Ag/ZnO 92/8WP<br />|91 - 93||9.8 PX: |2.0|86|50|60 - 95|||Powder Metallurgy<br />with Ag backing a) perpendicular to extrusion directionindivid.|2|-|Ag/ZnO 92/8WPW25<br />|91 - 93b|Ag<sub>2</sub>WO<sub>4</sub>|9.6|2.08|83|48|65 - 105|||Powder Metallurgy<br />c) coated|2|-|Ag/ZnO 90/10WPW25<br />|89 - 91|Ag<sub>2</sub>WO<sub>4</sub>|9.6|2.7|79|46|65 - 110|||Powder Metallurgy<br />c) parallel to extrusion directioncoated|2|}</figtable>
Fig. 1 = Wires, Rods, Contact rivets, 2.114: Micro structure of Ag/SnO<sub>2</sub> 88/12 TOS F: a) perpendicular to extrusion directionb) parallel to extrusion direction= Strips, Profiles, Contact tips
Fig. 2.115: Micro structure of Ag/SnO<sub>2</sub> 86/14 WPC: a) perpendicular to extrusion direction
b) parallel to extrusion direction, 1) AgSnO<sub>2</sub> contact layer, 2) Ag backing layer
Fig. 2.116<div class="multiple-images"><figure id="fig:Strain hardening of Ag ZnO 92 8 PW25"> [[File: Micro structure Strain hardening of Ag/SnOZnO 92 8 PW25.jpg|left|thumb|<subcaption>2<Strain hardening of Ag/sub> ZnO 92/8 WTOS F: a) perpendicular to extrusion directionb) parallel to extrusion direction,1) AgSnOPW25 by cold working<sub/caption>2]]</subfigure> contact layer, 2) Ag backing layer
Fig. 2.117<figure id="fig: Micro structure Softening ofAg ZnO 92 8 PW25"> [[File:Softening of Ag/SnOZnO 92 8 PW25.jpg|left|thumb|<subcaption>2<Softening of Ag/sub> 88ZnO 92/12 WPD: parallel to extrusion direction8 PW25 after annealing for 1) AgSnOhr after 30% cold working<sub/caption>2]]</subfigure> contact layer, 2) Ag backing layer
Fig. 2.118<figure id="fig: Micro structure Strain hardening ofAg ZnO 92 8 WPW25"> [[File:Strain hardening of Ag/SnOZnO 92 8 WPW25.jpg|left|thumb|<subcaption>2Strain hardening of Ag/ZnO 92/8 WPW25 by cold working</subcaption> 88/12 WPX:parallel to extrusion direction]]1) AgSnO<sub>2</subfigure> contact layer, 2) Ag backing layer
Fig. 2.119<figure id="fig:Softening of Ag ZnO 92 8 WPW25"> [[File: Micro structure Softening of Ag/SnOZnO 92 8 WPW25.jpg|left|thumb|<subcaption>2Softening of Ag/ZnO 92/8 WPW25 after annealing for 1hr after different degrees of cold working</subcaption> 86/14 WPX: a) perpendicular to extrusion direction]]b) parallel to extrusion direction, 1) AgSnO<sub>2</subfigure> contact layer, 2) Ag backing layer
Table 2<figure id="fig:Micro structure of Ag ZnO 92 8 PW25"> [[File:Micro structure of Ag ZnO 92 8 Pw25.27jpg|left|thumb|<caption>Micro structure of Ag/ZnO 92/8 PW25: Physical Properties of Powder Metallurgical Silver-Metal Oxide Materialsa) perpendicular to extrusion direction b) parallel to extrusion direction</caption>]]with Fine Silver Backing Produced by the Press-Sinter-Repress Process</figure>
*'''Silver–zinc oxide (DODURIT <figure id="fig:Micro structure of Ag ZnO) materials'''92 8 WPW25"> Silver zinc oxide (DODURIT [[File:Micro structure of Ag ZnO92 8 WPW25.jpg|right|thumb|<caption>Micro structure of Ag/ZnO 92/8 WPW25:a) perpendicular to extrusion direction b) parallel to extrusion direction, 1) Ag/ZnO contact materials with mostly 6 - 10 wt% oxidecontent including other small metal oxides are produced exclusively by powdermetallurgy ''(Figs. 2.120 – layer, 2.125)'' ''(Table 2.28)''. Adding Agbacking layer<sub/caption>2]]</subfigure>WO<sub>4</subdiv> in the process b)as described in the preceding chapter on Ag/SnO<subdiv class="clear">2</subdiv> has proven most effectivefor applications in AC relays, wiring devices, and appliance controls. Just likewith the other Ag metal oxide materials, semi-finished materials in strip and wireform are used to manufacture contact tips and rivets.Because of their high resistance against welding and arc erosion Ag/ZnOmaterials present an economic alternative to Cd free Ag-tin oxide contactmaterials ''(Tables 2.30 and 2.31)''.
Table 2.28: Physical and Mechanical Properties as well as Manufacturing Processes and
Forms of Supply of Extruded Silver-Zinc Oxide (DODURIT ZnO) Contact
Fig<figtable id="tab:tab2. 29"><caption>'''<!--Table 2.12029: Strain hardening -->Optimizing ofSilver–Tin Oxide Materials Regarding their Switching Properties and Forming Behavior'''</caption><table class="twocolortable"><tr><th><p class="s12">Material/</p><p class="s12">Material Group</p></th><th><p class="s12">Special Properties<th colspan="2"></p></th></tr><tr><td><p class="s12">Ag/SnO<sub>2</sub> PE</p></td><td><p class="s12">Especially suitable for automotive relays</p><p class="s12">(lamp loads)</p></td><td><p class="s12">Good formability (contact rivets)</p></td></tr><tr><td><p class="s12">Ag/SnO<sub>2</sub> TOS F</p></td><td><p class="s12">Especially suited for high inductive</p><p class="s12">DC loads</p></td><td><p class="s12">Very good formability (contact rivets)</p></td></tr><tr><td><p class="s12">Ag/ZnO 92SnO<sub>2</sub> WPD</p></td><td><p class="s12">Especially suited for severe loads (AC-4)</p><p class="s12">and high switching currents</p></td><td/></tr><tr><td><p class="s12">Ag/SnO<sub>2</sub> W TOS F</p></td><td><p class="s12">Especially suitable for high inductive DC</p><p class="s12">loads</p></td><td/></tr></table></8 PW25 by cold workingfigtable>
Fig. 2.121: Softening of Ag/ZnO 92/8 PW25
after annealing for 1 hr after 30% cold working
Fig. <figtable id="tab:Contact and Switching Properties of Silver–Metal Oxide Materials"><caption>'''<!--Table 2.12230: Strain hardening -->Contact and Switching Properties ofAgSilver–Metal Oxide Materials'''</ZnO 92/8 WPW25by cold workingcaption>
Fig. {| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material!Properties|-|Ag/SnO<sub>2.123: Softening </sub><br />|Environmentally friendly materials,<br />Very high resistance against welding during current-on-switching,<br />Weld resistance increases with higher oxide contents,<br />Low and stable contact resistance over the life of the device and good<br />temperature rise properties through use ofspecial additives,<br />High arc erosion resistance and contact life,<br />Very low and flat material transfer during DC load switching,<br />Good arc moving and very good arc extinguishing properties|-|Ag/ZnO 92<br />|Environmentally friendly materials,<br /8 WPW25 after annealing >High resistance against welding during current-on-switching<br />(capacitor contactors),<br />Low and stable contact resistance through special oxide additives,<br />Very high arc erosion resistance at high switching currents,<br />Less favorable than Ag/SnO<sub>2</sub> for electrical life and material transfer,<br />With Ag<sub>2</sub>WO<sub>4</sub> additive especially suitable forAC relays|}1hr after different degrees of cold working</figtable>
Fig. 2.115: Micro structure of Ag/ZnO 92/8 Pw25: a) perpendicular to extrusion direction
b) parallel to extrusion direction
Fig. <figtable id="tab:Application Examples of Silver–Metal Oxide Materials"><caption>'''<!--Table 2.11631: Micro structure -->Application Examples of Silver–Metal Oxide Materials'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p></th><th><p class="s12">Application Examples</p></th></tr><tr><td><p class="s12">Ag/ZnO 92SnO<sub>2</sub><span class="s48"></span></p></td><td><p class="s12">Micro switches, Network relays, Automotive relays, Appliance switches,</p><p class="s12">Main switches, contactors, Fault current protection relays (paired against</p><p class="s12">Ag/8 WPW25:a) perpendicular to extrusion directionbC) parallel to extrusion direction, 1(Main) Power switches</p></td></tr><tr><td><p class="s12">Ag/ZnO contact layer</p></td><td><p class="s12">Wiring devices, AC relays, 2Appliance switches, Motor-protective circuit</p><p class="s12">breakers (paired with Ag/Ni or Ag/C) , Fault current circuit breakers paired againct Ag backing layer/C, (Main) Power switches</p></td></tr></table></figtable>
====Silver–Graphite Materials====Ag/C contact materials are usually produced by powder metallurgy with graphite contents of 2 – 6 wt% (<xr id="tab:tab2.32"/>)<!--(Table 2.29: Optimizing 32)-->. The earlier typical manufacturing process of Silver–Tin Oxide Materials Regarding their SwitchingProperties single pressed tips by pressing - sintering - repressing (PSR) has been replaced in Europe for quite some time by extrusion. In North America and Forming Behaviorsome other regions however the PSR process is still used to some extend mainly for cost reasons.
Table The extrusion of sintered billets is now the dominant manufacturing method for semi-finished AgC materials<!--[[#figures3|(Figs. 64 – 67)]]<!--(Figs. 2.126 – 2.129)-->. The hot extrusion process results in a high density material with graphite particles stretched and oriented in the extrusion direction [[#figures4|(Figs. 68 – 71)]]<!--(Figs. 2.30130 – 2.133)-->. Depending on the extrusion method in either rod or strip form, the graphite particles can be oriented in the finished contact tips perpendicular or parallel to the switching contact surface (<xr id="fig: Contact Micro structure of Ag C 95 5"/><!--(Fig. 2.131)--> and Switching Properties <xr id="fig:Micro structure of Silver–Metal Oxide MaterialsAg C 96 4 D"/>)<!--(Fig. 2.132)-->.
Table 2Since the graphite particles in the Ag matrix of Ag/C materials prevent contact tips from directly being welded or brazed, a graphite free bottom layer is required.31: Application Examples This is achieved by burning out (de-graphitizing) the graphite selectively on one side of Silver–Metal Oxide Materialsthe tips.
====Silver–Graphite (GRAPHOR)-Materials====Ag/C (GRAPHOR) contact materials are usually produced exhibit on the one hand an extremely high resistance to contact welding but on the other have a low arc erosion resistance. This is caused by powder metallurgythe reaction of graphite with graphite contents of 2 – 5 wt% ''(Table 2.32)''the oxygen in the surrounding atmosphere at the high temperatures created by the arcing. The earlier typicalmanufacturing process of single pressed tips by pressing - sintering - repressing(PSR) has been replaced in Europe weld resistance is especially high for quite some time by extrusionmaterials with the graphite particle orientation parallel to the arcing contact surface. In NorthAmerica and some other regions however Since the contact surface after arcing consists of pure silver, the contact resistance stays consistantly low during the electrical life of the PSR process is still used to someextend mainly for cost reasonscontact parts.
The extrusion A disadvantage of sintered billets is now the dominant manufacturing method forsemi-finished AgC Ag/C materials ''(Figsis their rather high erosion rate. 2.126 – 2.129)''. The hot extrusion processresults in In materials with parallel graphite orientation this can be improved, if a high density part of the graphite is incorporated into the material with graphite particles stretched and oriented (Ag/C DF) inthe extrusion direction ''form of fibers (Figs. 2<xr id="fig:Micro structure of Ag C DF"/>)<!--(Fig.130 – 2.133)''-->. Depending on the extrusionmethod in either rod or strip form The weld resistance is determined by the total content of graphite particles can be oriented in thefinished contact tips perpendicular (GRAPHOR) or parallel (GRAPHOR D) to theswitching contact surface ''(Figs. 2.131 and 2.132)''.
Since the Ag/C tips with vertical graphite particles particle orientation are produced in the Ag matrix a specific sequence: Extrusion to rods, cutting of Ag/C materials prevent contactdouble thickness tips from directly being welded or brazed, burning out of graphite to a graphite free bottom controlled layer isrequiredthickness, and a second cutting to single tips. This is achieved by either burning out Such contact tips are especially well suited for applications which require both, a high weld resistance and a sufficiently high arc erosion resistance (de<xr id="tab:tab2.33"/>)<!-graphitizing-(Table 2.33) the graphiteselectively on one side of the tips or by compound extrusion -->. For attachment of a Ag/C billetcovered with a fine silver shelltips welding and brazing techniques are applied.
Welding the actual process depends on the material's graphite orientation. For Ag/C contact materials exhibit on tips with vertical graphite orientation the one hand an extremely high resistance tocontacts are assembled with single tips. For parallel orientation a more economical attachment starting with contact material in strip or profile tape form is used in integrated stamping and welding but on the other have a low arc erosion resistance. This iscaused by the reaction of graphite operations with the oxygen in the surroundingatmosphere at the high temperatures created by tape fed into the arcing. The weld resistanceis especially high for materials with station, cut off to tip form and then welded to the graphite particle orientation parallel to carrier material before forming thearcing final contact surfaceassembly part. Since the contact surface after arcing consists of puresilver the contact resistance stays consistently For special low during energy welding, the electrical life Ag/C profile tapes can be pre-coated with a thin layer of thecontact partshigh temperature brazing alloys such as CuAgP.
A disadvantage of the In a rather limited way, Ag/C materials is their rather high erosion rate. In materialswith parallel 2 – 3 wt% graphite orientation this can be improved if part of the graphite isincorporated into the material produced in the wire form of fibers (GRAPHOR DF), ''(Fig. 2.133)''.The weld resistance is determined by the total content of graphite particlesand headed into contact rivet shape with low head deformation ratios.
The main applications for Ag/C tips with vertical graphite particle orientation materials are produced in a specificsequence: Extrusion to rodsprotective switching devices such as miniature molded case circuit breakers, cutting of double thickness tipsmotor-protective circuit breakers, burning out ofgraphite to a controlled layer thicknessand fault current circuit breakers, and a second cutting to single tips.Such contact tips are especially well suited for applications which require bothwhere during short circuit failures,a high weld highest resistance and a sufficiently high arc erosion resistance ''against welding is required (<xr id="tab:tab2.34"/>)<!--(Table 2.3334)''-->.For attachment higher currents the low arc erosion resistance of Ag/C tips welding is compensated by asymmetrical pairing with more erosion resistant materials such as Ag/Ni, Ag/W and brazing techniques are appliedAg/WC.
welding the actual process depends on the material's graphite orientation. For<div class="multiple-images"><figure id="fig:Strain hardening of Ag/C tips with vertical graphite orientation the contacts are assembled with96 4 D">single tips[[File:Strain hardening of Ag C 96 4 D. For parallel orientation a more economical attachment starting withcontact material in strip or profile tape form is used in integrated stamping andwelding operations with the tape fed into the weld station, cut off to tip form andthen welded to the carrier material before forming the final contact assemblypart. For special low energy welding the jpg|left|thumb|<caption>Strain hardening of Ag/C profile tapes GRAPHOR D and DF96/4 by cold working</caption>]]can be pre-coated with a thin layer of high temperature brazing alloys such asCuAgP.</figure>
In a rather limited way, <figure id="fig:Softening of Ag C 96 4 D"> [[File:Softening of Ag C 96 4 D.jpg|left|thumb|<caption>Softening of Ag/C with 2 – 3 wt% graphite can be produced in wire96/4 after annealing</caption>]]form and headed into contact rivet shape with low head deformation ratios.</figure>
The main applications for <figure id="fig:Strain hardening of Ag/C materials are protective switching devices suchDF"> as miniature molded case circuit breakers, motor-protective circuit breakers,and fault current circuit breakers, where during short circuit failures highestresistance against welding is required ''(Table 2.34)''[[File:Strain hardening of Ag C DF. For higher currents the lowarc erosion resistance jpg|left|thumb|<caption>Strain hardening of Ag/C is compensated DF by asymmetrical pairing withcold working</caption>]]more erosion resistant materials such as Ag</Ni and Ag/W.figure>
Fig. 2.126<figure id="fig:Softening of Ag C DF after annealing"> Strain hardening[[File:Softening of Ag C DF after annealing.jpg|left|thumb|<caption>Softening of Ag/C 96DF after annealing</4 Dcaption>]]by cold working</figure>
Fig. 2.127<figure id="fig:Micro structure of Ag C 97 3"> Softening [[File:Micro structure of Ag C 97 3.jpg|left|thumb|<caption>Micro structure of Ag/C 9697/4 D after3: a) perpendicular to extrusion direction b) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag backing layer</caption>]]annealing</figure>
Fig. 2.128<figure id="fig: Strain hardeningMicro structure of Ag C 95 5"> [[File:Micro structure of Ag C 95 5.jpg|left|thumb|<caption>Micro structure of Ag/C DF by cold working95/5: a) perpendicular to extrusion direction b) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag backing layer</caption>]]</figure>
Fig. 2.129<figure id="fig: SofteningMicro structure of Ag C 96 4 D"> [[File:Micro structure of Ag C 96 4 D.jpg|left|thumb|<caption>Micro structure of Ag/C DF after annealing96/4: a) perpendicular to extrusion direction b) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag backing layer</caption>]]</figure>
Fig<figure id="fig:Micro structure of Ag C DF"> [[File:Micro structure of Ag C DF. 2.130: jpg|left|thumb|<caption>Micro structure of Ag/C 97/3DF: a) perpendicular to extrusion directionb) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag /Ni 90/10 backing layer</caption>]]</figure></div><div class="clear"></div>
Fig<figtable id="tab:tab2. 32"><caption>'''<!--Table 2.13132: Micro structure -->Physical Properties of Ag/C 95Silver–Graphite Contact Materials'''</5: a) perpendicular to extrusion directionb) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag backing layercaption>
Fig{| class="twocolortable" style="text-align: left; font-size: 12px"|-!Material !Silver Content<br />[wt%]!Density<br />[g/cm<sup>3</sup>]!Melting Point<br />[°C]!Electrical Resistivity<br />[μΩ·cm]!colspan="2" style="text-align:center"|Electrical<br />Conductivity<br />[% IACS] [MS/m]!Vickers-Hardnes<br />HV10<br />42 - 45|-|Ag/C 98/2|97.5 - 98.5|9.5|960|1.85 - 1.92|90 - 93|48 - 50|42 - 44|-|Ag/C 97/3|96. 5 - 97.5|9.1|960|1.92 - 2.132: Micro structure of 0|86 - 90|45 - 48|41 - 43|-|Ag/C 96/4 D: a) perpendicular to extrusion directionb) parallel to extrusion direction, 1) |95.5 - 96.5|8.7|960|2.04 - 2.13|81 - 84|42 - 46|40 - 42|-|Ag/C contact layer95/5|94.5 - 95.5|8.5|960|2.12 - 2.22|78 - 81|40 - 44|40 - 60|-|AgC DF<br />GRAPHOR DF[[#text-reference1|<sup>1</sup>]]|95.7 - 96.7|8.7 - 8.9|960|2.27 - 2.50|69 - 76|40 - 44|-|}<div id="text-reference1"><sub>1</sub> Graphite content 3.8 wt%, 2) Ag backing layerGraphite particles and fibers parallel to switching surface</div></figtable>
Fig. 2.133: Micro structure of Ag/C DF: a) perpendicular to extrusion direction
b) parallel to extrusion direction, 1) Ag/C contact layer, 2) Ag/Ni 90/10 backing layer
Table 2.32: Physical Properties of Silver–Graphite (GRAPHOR) Contact Materials
Table 2.33: Contact and Switching properties of Silver–Graphite (GRAPHOR) Contact Materials
<figtable id="tab:tab2.33"><caption>'''<!--Table 2.3433: Application Examples -->Contact and Forms Switching properties of Supply Silver–Graphite Contact Materials'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p></p></th><th><p class="s11">Properties</p></th></tr><tr><td><p class="s12">Ag/C</p></p></td><td><p class="s12">Highest resistance against welding during make operations at high currents,</p><p class="s12">High resistance against welding of Silver–closed contacts during short circuit,</p><p class="s12">Increase of weld resistance with higher graphite contents, Low contact resistance,</p><p class="s12">Low arc erosion resistance, especially during break operations, Higher arc erosion with increasing graphite contents, at the same time carbon build-up on switching chamber walls increases, silver-graphite with vertical orientation has better arc erosion resistance, parallel orientation has better weld resistance,</p><p class="s12">Limited arc moving properties, therefore paired with other materials,</p><p class="s12">Limited formability,</p><p class="s12">Can be welded and brazed with decarbonized backing, GRAPHOR DF is optimized for arc erosion resistance and weld resistance</p></td></tr></table>Graphite (GRAPHOR) Contact Materials</figtable>
Pre<figtable id="tab:tab2.34"><caption>'''<!--Table 2.34:--Production >Application Examples and Forms of Supply of Silver– Graphite Contact Materials'''</caption><table class="twocolortable"><tr><th><p class="s12">Material</p><p class="s12"></p></th><th><p class="s12">Application Examples</p></th><th><p class="s12">Form of Supply</p></th></tr><td><p class="s12">Ag/C 98/2</p><p class="s12"></p></td><td><p class="s12">Motor circuit breakers, paired with Ag/Ni</p></td><td><p class="s12">Contact tips, brazed and welded contact parts, some contact rivets </p><p class="s12">Contact profiles (weld tapes), Contact tips, brazed and welded contact parts</p></td></tr><tr><td><p class="s12">Ag/C 97/3</p><p class="s12"></p><p class="s12">Ag/C 96/4</p><p class="s12"></p><p class="s12">Ag/C 95/5</p><p class="s12"></p><p class="s12">Ag/C DF</p></td><td><p class="s12">Circuit breakers, paired with Cu, Motor-protective circuit breakers, paired with Ag/Ni,</p><p class="s12">Fault current circuit breakers, paired with Ag/Ni, Ag/W, Ag/WC, Ag/SnO<sub>2</sub><span class="s45"></span>, Ag/ZnO,</p><p class="s12">(BildMain)Power switches, paired with Ag/Ni, Ag/W</p></td><td><p class="s12">Contact tips, brazed and welded contact</p><p class="s12">parts, some contact rivets with</p><p class="s12">Ag/C97/3</p></td></tr></table></figtable>
==References==
[[Contact Materials for Electrical Engineering#References|References]]
 
[[de:Werkstoffe_auf_Silber-Basis]]