Report on Carcinogens Background Document for Cobalt–Tungsten Carbide: Powders and Hard Metals.

摘要

This candidate substance includes powders and dusts (either unsintered or sintered) containing both cobalt and tungsten carbide and hard metals containing both cobalt and tungsten carbide (hereafter referred to as “hard metals”). Hard metals are also referred to as cemented (or sintered) carbides, or simply as tungsten carbides. Cobalt–tungsten carbide hard metals are composites of tungsten carbide particles (either tungsten carbide alone or in combination with smaller amounts of other carbides) with metallic cobalt powder as a binder, pressed into a compact, solid form at high temperatures by a process known as “sintering.” Cobalt–tungsten carbide hard metals have properties of extreme hardness, abrasion resistance, and toughness and are used primarily in cutting tools and wear-resistant machine parts.