The effect of SiO/sub 2/ contaminated silver rivets on contact spot degradation under various arcing properties

Surface contamination introduced by deburring electrical contacts with mineral silicon (SiO/sub 2/), will affect the contact spot in different ways by varying the arcing properties. Those factors which affect contact resistance were investigated. The investigation demonstrated that contact spot degradation was caused by absorption of organic vapors during switching, rather than decomposition of the mineral silicon (SiO/sub 2/) on the surface of fine silver rivets. This degradation mechanism may be reduced by sustaining an arc at switching currents of 2, 5 and 10 amps at 12.5 VDC. Furthermore, increasing the contact force from 50 grams (0.5 N) to 100 grams (1 N) produced significant reduction in the kinetics of the degradation mechanism in the contact spot at low switching currents (2 amps). The degradation of the contact spot during switching was explained as interactions among mineral silicon (SiO/sub 2/) concentration on the rivet's surface, arcing properties and contact force used during switching.