Tungsten carbide is an inorganic chemical compound that contains equal numbers of tungsten and carbon atoms. It is sometimes colloquially referred to as simply "carbide." In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery, tools, abrasives, as well as men's jewelry.
The notable and rare combination of physical properties possessed by tungsten carbide makes it useful for a variety of applications. It is extremely strong and wear-resistant. There are only a few materials on earth that can be used to cut or engrave it, with industrial diamond abrasives being one of these. Its tensile strength is very high, but it is brittle under high pressures as a result. The melting point is also very high, at 5,200°F (2,870°C). To boil, it must be heated much further, to 10,382°F (6,000°C).
This compound can be made by reacting tungsten and carbon at temperatures of around 2,552 to 3,632°F (1,400 to 2,000°C). It is then often made into mills and cutting tools for industrial use, which are able to withstand heavy use and high temperatures. Military organizations also use it in armor-piercing ammunition as an alternative to depleted uranium because of its very high density and hardness level. Some sporting goods are made stronger and more durable by the addition of carbide. Trekking poles used by hikers, for instance, use carbide tips in order to gain traction on hard or rocky surfaces.
Several common consumer goods contain tungsten carbide, including razor blades and the rotating tips of ballpoint pens. It has also become increasingly common for it to be used in men's wedding bands. When used in this way, the bands have a dark hue that can be polished to a mirror-like shine. Due to the toughness of the material, these rings will remain shiny and scratch-free for decades.
Wedding bands made of carbide also contain other materials known as binders, usually metals such as nickel and cobalt. Cobalt has been known to cause allergic reactions on the skin of the wearer, so many manufacturers are turning toward substitute materials. Despite the common misconception that carbide rings cannot be removed in emergency situations, the jeweler's saws used in emergency rooms and jewelry shops can cut through any material that a ring might be made of.
It is important to note that tungsten carbide is made in nearly two dozen different grades that have different properties, depending on what each will be used for. They are almost all variations of just a few parameters: grain size, hardness, and the degree to which a binder is used. Generally, the higher the percentage of the finished product that is composed of binding materials like nickel, the softer it will be and the more it will wear. The size of the original powder grains makes slightly less difference, but can affect the amount of shock that the product will be able to withstand.