Electrical contacts and contact materials are soft, high-conductivity, oxidation- resistant materials that are used in circuit breakers, relays, switches, and electrical discharge machining (EDM) applications.  They often have a second phase in order to provide anti-welding and/or arc resistance. Electrical contacts and contact materials are used in many different type of contacts. Battery contacts usually consist of a low-cost base metal that is plated with a layer of high-conductivity metal. Contact probes or spring contacts are brush assemblies with a plunger-style configuration and an internal helical spring. EDM electrodes are designed specifically for EDM applications. Electrical brushes are used in conjunction with slip rings and other contact surfaces to maintain an electrical connection in mobile or rotary applications. Furnace electrodes are used to heat and melt metals or ceramics in arc furnaces. Welding electrodes are designed for resistance, arc, or plasma welding. Specialty electrical contacts and contact materials are also commonly available.