Tarnishing Studies on Contact Materials

This paper presents some further results of the IBM Electrical Contacts Field Program, introduced previously. The degradation of contact materials over a period of time at six field sites is described as a function of atmospheric pollutants. The results of short-term laboratory exposures of some of these metals in tarnishing environments are compared and contrasted with the field results. Methods that have been found to significantly reduce the extent of tarnish formation on electric contact materials or to reduce the effect of such tarnish products on contact behavior are discussed.