Physical Effects in Sliding and Connector Contacts

6.4.5 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

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