In the field of electrical resistance heating, a variety of materials are available for use as heating elements. They include METALLIC ALLOYS (Nickel-chrome, Iron-ChromeAluminum,

Tungsten, Molybdenum, and Tantalum), CERAMIC MATERIALS (Silicon Carbide, and at one time Zirconium Oxide), CERAMIC METALS (Molybdenum Disilicide, Lanthanum Chromite), PRECIOUS METALS (Platinum and Platinum Rhodium Alloys), and GRAPHITE/CARBON based materials. These materials may be divided into two separate groups; those that can operate at elevated temperatures in the presence of oxygen and those that must be protected from oxygen.