Carbides and Carbide Materials (hardmetals) Information
Carbides and carbide materials have excellent wear resistance and high hot hardness. They are sometimes referred to as hardmetals. Applications include wear parts and tooling, chemical and material processing, building and construction, and walls and roofing. Carbides are also used in high voltage (HV), radio frequency, and microwave applications. Carbides and carbide materials are supplied in a variety of shapes, sizes, and forms. They differ in terms of thermal, electrical, and mechanical specifications, as well as physical and optical properties.
Carbides are binary compounds of carbon and an element of lower or comparable electronegativity. These carbon-containing alloys represent the doping of a metal and a semiconductor, such as steel. Carbides are produced typically in an electric arc furnace. Products such as pure silicon are made via the Lely process, in which the carbon powder is sublimated in argon and then redeposited.
Types of Carbides and Carbide Materials (hardmetals)
Examples of different types of carbides include boron carbide, silicon carbide, and tungsten carbide (WC).
Boron carbide (B4C) has higher hardness than alumina or silicon carbide. Its oxidation product (B2O3) provides a protective skin at high temperatures (> 800oC). Because of its high hardness and wear resistance, boron carbide is applied in low-temperature applications such as grinding wheel dressers, and abrasive blast or water jet nozzles. Boron carbide is used in grit blasting nozzles, high pressure water jet cutter nozzles, scratch and wear resistant coatings, cutting tools and dies, abrasives, and neutron absorber in nuclear reactors.
Silicon carbide (SiC) is a compound of silicon metalloid and oxygen. Typically, SiC is used in the alpha silicon carbide structural form. Silicon carbide is a black, high-hardness ceramic that is usually harder than alumina. Depending on the addition of impurities SiC may be green or black in color. Fully-dense SiC can be transparent (moissanite). Silicon carbide is used in structural materials, astronomy, disc brakes, diesel particulate filters, cutting tools, and heating elements. High purity silicon carbide powder is used in the production of semiconductors.
Tungsten carbide (WC) materials are compounds of a tungsten metal and carbon. Metal carbides are also known as hard metals. Metal carbides have high hardness and high hot hardness, which makes them useful for cutting tools, forming dies, and other wear applications. Metal carbides often use cobalt, nickel, or intermetallic metal bonds between grains (cemented carbides), which results in increased toughness compared a pure carbide or ceramic. Tungsten carbide is used for armor-piercing ammunition and in high-temperature alloys.
Other types of carbide materials include calcium carbide, aluminum carbide, titanium carbide, and other compounds of a metal or metalloid and carbon.