Current Topics in the Surface Chemistry of Electric Contacts

This paper describes recent work in the science of the separable electronic pressure contact with emphasis on chemical factors in performance. The following topics are discussed: growth and morphology of sulfide tarnish films which creep across the interface between gold plate and silver or copper alloys and degrade contact performance; the formation and structure of corrosion solids on porous gold electroplated contacts, and which originate in atmospheres polluted with sulfur dioxide or hygroscopic dusts; new developments in measuring the porosity in precious metal plates; the critical dependence of the porosity of gold plate on substrate roughness; and new concepts for developing electronic connectors with contacts made of base metals.