Effect of surface contamination on electric contact performance

Surface contamination is one of the most serious causes of failure of connectors, relays, switches, slip rings, and other devices. The most common types of contamination are oxide and corrosion products, particulates, films formed by thermal diffusion processes, debris produced by mechanical wear and fretting, outgassing and condensation on contact surfaces of volatiles from noncontact materials, and those that originate in the manufacturing processes. Examples of contamination, its effects on contact resistance and device reliability, and the principles of contact resistance probing for its detection and characterization are discussed in detail with examples from the recent literature.