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

Revision as of 13:50, 17 February 2014

6.4.5 Physical Effects in Sliding and Connector Contacts

  • Mechanical wear of sliding contacts

dV/dx = k x FK /3 HW 3 dV/dx Wear volume in mm 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 -4 Silver – Silver 120 x 10 -4 Platinum – Platinum 400 x 10 -4 Silver – Platinum 1.3 x 10 Coefficient of fractional wear k during wear loss -4 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

Fig. 6.15: 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

  • Contact behavior of connectors

Fig. 6.16: Contact resistance R as a function k of the contact force F for different surface k coating materials. Measured against a spherical gold probe; I = 10 mA, U < 20 mV

Fig. 6.17: Contact resistance R as a function k of the fretting wear cycles for different surface coating materials

Tab.6.4: Surface Coating Materials for Connectors

References

References