Difference between revisions of "Physical Effects in Sliding and Connector Contacts"

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===6.4.5 Physical Effects in Sliding and Connector Contacts===
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===<!--6.4.5-->Physical Effects in Sliding and Connector Contacts===
  
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*'''Mechanical wear of sliding contacts'''
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'''Mechanical wear of sliding contacts'''
  
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{| class="twocolortable" style="text-align: left; font-size: 12px;width:40%"
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<table class="twocolortable" style="text-align: left; font-size:12px;width:40%">
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|-
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<tr>
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|dV/dx = k x F<sub>K</sub> /3 H<sub>W</sub>
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<td>dV/dx = k x F<sub>K</sub> /3 H<sub>W</sub></td>
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|-
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</tr><tr>   
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|dV/dx    Wear volume in mm<sup>3</sup> per slide path length in mm
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<td>dV/dx    Wear volume in mm<sup>3</sup> per slide path length in mm</td>
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|-
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</tr><tr>
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|k        Coefficient of frictional wear
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<td>k        Coefficient of frictional wear</td>
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|-
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</tr><tr>
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|H<sub>W</sub>        Hardness of the softer material <br />(Brinell or Vickers units)
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<td>H<sub>W</sub>        Hardness of the softer material <br />(Brinell or Vickers units)</td>
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|-
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</tr><tr>
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|F<sub>K</sub>        Contact force in cN
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<td>F<sub>K</sub>        Contact force in cN</td>
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|-
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</tr><tr>
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|'''Wear coefficient k during material transfer'''
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<td>'''Wear coefficient k during material transfer'''</td>
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|-
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</tr><tr>
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|Silver – Silver 120 x 10<sup>-4</sup>
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<td>Silver – Silver 120 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Platinum – Platinum 400 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Silver – Platinum 1.3 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>'''Coefficient of fractional wear k during wear loss'''</td>
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</tr><tr>
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<td>Silver – silver 8 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Gold – gold 9 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Platinum – platinum 40 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Silver – gold 9 x 10<sup>-4</sup></td>
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</tr><tr>
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<td>Silver – platinum 5 x 10<sup>-4</sup></td>
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</tr>
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</table>
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'''Contact behavior of connectors'''
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<div class="multiple-images">
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[[File:Coefficient of frictional wear for the wear loss of sliding contacts Silver Silver.jpg|left|thumb|Figure 1: Coefficient of frictional wear for the wear loss of sliding contacts Silver/Silver and hard gold/hard gold as a function of the contact force]]
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<figure id="fig:Contact resistance Rk as a function of the contact force Fk">
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[[File:Contact resistance Rk as a function of the contact force Fk.jpg|left|thumb|Figure 2: Contact resistance R<sub>k</sub> as a function of the contact force F<sub>k</sub> for different surface coating materials. Measured against a spherical gold probe; I = 10 mA, U < 20 mV]]
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</figure>
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<figure id="fig:Contact resistance Rk as a function of the fretting wear cycles">
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[[File:Contact resistance Rk as a function of the fretting wear cycles.jpg|left|thumb|Figure 3: Contact resistance R<sub>k</sub> as a function of the fretting wear cycles for different surface coating materials]]
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</figure>
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</div>
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<div class="clear"></div>
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<figtable id="tab:Surface Coating Materials for Connectors">
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<caption>'''<!--Tab.6.4:-->Surface Coating Materials for Connectors'''</caption>
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{| class="twocolortable" style="text-align: left; font-size: 12px"
 
|-
 
|-
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|Platinum – Platinum 400 x 10<sup>-4</sup>
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!Manufacturing method
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!Coating materials
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!Intermediate layer
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!Hardness HV
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!Frictional factor
 
|-
 
|-
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|Silver – Platinum 1.3 x 10<sup>-4</sup>
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|Electroplating
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|Tin<br />Nickel<br />Nickel-phosphorus (NiP 6 - 15)<br />Silver<br />Hard gold (< 0.3 wt% Ni or Co)<br />Palladium with Au- flash (<0,2μm)<br />Palladium-nickel with Au-flash (<0.2μm)
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|For brass: Copper or Nickel<br /> <br /> <br /> <br />Nickel, Nickel-phosphorus<br />Nickel<br />Nickel
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|50 - 90<br />300 - 600<br />500 - 1100<br />70 - 100<br />100 - 200<br />250 - 300<br />300 - 400
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|0.5 - 1<br /> <br /> <br />0.5 - 0.8<br />0.2 - 0.5<br />0.2 - 0.5<br />0.2 - 0.5
 
|-
 
|-
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|'''Coefficient of fractional wear k during wear loss'''
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|Cladding
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|Gold-nickel (AuNi 5 -10)<br />Silber-palladium (AgPd 10 - 30)
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|Nickel<br />Nickel
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|160 - 200<br />120 - 170
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|0.2 - 0.5<br />0.2 - 0.5
 
|-
 
|-
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|Silver – silver 8 x 10<sup>-4</sup>
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|Hot-dipped tinning
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|-
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|Tin
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|Gold – gold 9 x 10<sup>-4</sup>
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|Inter-metallic compound[[#text-reference|<sup>(1)</sup>]] Tin–copper
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|-
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|400 - 500
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|Platinum – platinum 40 x 10<sup>-4</sup>
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|
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|-
 
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|Silver – gold 9 x 10<sup>-4</sup>
 
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|-
 
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|Silver – platinum 5 x 10<sup>-4</sup>
 
 
|}
 
|}
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<div id="text-reference">(1) is formed during hot tinning process</div>
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</figtable>
  
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<div class="clear"></div>
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Fig. 6.15: Coefficient of frictional wear for the wear loss of sliding contacts Silver/Silver
 
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and hard gold/hard gold as a function of the contact force
 
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*'''Contact behavior of connectors'''
 
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Fig. 6.16: Contact resistance R as a function k
 
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of the contact force F for different surface k
 
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coating materials. Measured against a
 
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spherical gold probe; I = 10 mA, U < 20 mV
 
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Fig. 6.17: Contact resistance R as a function k
 
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of the fretting wear cycles for different surface
 
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coating materials
 
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Tab.6.4: Surface Coating Materials for Connectors
 
  
 
==References==
 
==References==
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
 
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
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[[de:Physikalische_Effekte_bei_Gleit-_und_Steckkontakten]]

Latest revision as of 12:45, 11 January 2023

Physical Effects in Sliding and Connector Contacts

Mechanical wear of sliding contacts

dV/dx = k x FK /3 HW
dV/dx Wear volume in mm3 per slide path length in mm
k Coefficient of frictional wear
HW Hardness of the softer material
(Brinell or Vickers units)
FK Contact force in cN
Wear coefficient k during material transfer
Silver – Silver 120 x 10-4
Platinum – Platinum 400 x 10-4
Silver – Platinum 1.3 x 10-4
Coefficient of fractional wear k during wear loss
Silver – silver 8 x 10-4
Gold – gold 9 x 10-4
Platinum – platinum 40 x 10-4
Silver – gold 9 x 10-4
Silver – platinum 5 x 10-4


Contact behavior of connectors

Figure 1: Coefficient of frictional wear for the wear loss of sliding contacts Silver/Silver and hard gold/hard gold as a function of the contact force
Figure 2: Contact resistance Rk as a function of the contact force Fk for different surface coating materials. Measured against a spherical gold probe; I = 10 mA, U < 20 mV
Figure 3: Contact resistance Rk as a function of the fretting wear cycles for different surface coating materials


Table 1: Surface Coating Materials for Connectors
Manufacturing method Coating materials Intermediate layer Hardness HV Frictional factor
Electroplating Tin
Nickel
Nickel-phosphorus (NiP 6 - 15)
Silver
Hard gold (< 0.3 wt% Ni or Co)
Palladium with Au- flash (<0,2μm)
Palladium-nickel with Au-flash (<0.2μm) 		For brass: Copper or Nickel



Nickel, Nickel-phosphorus
Nickel
Nickel 		50 - 90
300 - 600
500 - 1100
70 - 100
100 - 200
250 - 300
300 - 400 		0.5 - 1


0.5 - 0.8
0.2 - 0.5
0.2 - 0.5
0.2 - 0.5
Cladding Gold-nickel (AuNi 5 -10)
Silber-palladium (AgPd 10 - 30) 		Nickel
Nickel 		160 - 200
120 - 170 		0.2 - 0.5
0.2 - 0.5
Hot-dipped tinning Tin Inter-metallic compound(1) Tin–copper 400 - 500
(1) is formed during hot tinning process

References

References

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