What is the chemical formula of tungsten carbide

       

What is the chemical formula of tungsten carbide

Tungsten Carbide (Tungsten Carbide) is a compound composed of tungsten and carbon. The molecular formula is WC and the molecular weight is 195.85. Tungsten carbide is a black hexagonal crystal with metallic luster and hardness similar to diamond. It is a good conductor of electricity and heat. Tungsten carbide is insoluble in water, hydrochloric acid and sulfuric acid, but easily soluble in a mixed acid of nitric acid and hydrofluoric acid. Pure tungsten carbide is fragile, and if a small amount of titanium, cobalt and other metals are added, the brittleness can be reduced. Tungsten carbide used as a steel cutting tool is often added with titanium carbide, tantalum carbide or their mixture to improve the anti-knock ability. The chemical properties of tungsten carbide are stable, and tungsten carbide powder is used in cemented carbide production materials. Follow the editor to learn about tungsten carbide!

Development history of tungsten carbide

 

Since 1893, German scientists have used tungsten trioxide and carbon to be heated to a high temperature in an electric furnace to produce tungsten carbide, and tried to use its high melting point and high hardness to produce wire drawing dies in order to replace diamond materials. . However, due to its brittleness, easy cracking and low toughness, tungsten carbide has not been used in industrial applications. In the 1920s, German scientist Karl Schroter discovered that pure tungsten carbide cannot adapt to the drastic stress changes formed in the drawing process. Only by adding low-melting metal to WC can the roughness be made without reducing the hardness. Has a certain degree of toughness. Schroter first proposed the method of powder metallurgy in 1923, that is, tungsten carbide is mixed with a small amount of iron group metals (iron, nickel, cobalt), then pressed into a shape and sintered in hydrogen at a temperature higher than 1300 ℃ to produce a hardness alloy Patents.

 

Physical properties

 

It is a black hexagonal crystal and a gray powder with metallic luster, belonging to the hexagonal crystal system. It is soluble in mixed acid of nitric acid and hydrofluoric acid and aqua regia, insoluble in cold water, very hard, and has a large elastic modulus (72700kg/mm2).

 

Chemical properties

 

Active oxidation begins when the temperature is above 500°C in the air, with weak anti-oxidation ability and strong acid resistance.

 

Chemical reaction formula: W + C = WC Note: React at 1150℃.

 

It does not react with chlorine below 400°C; it can react violently with fluorine at room temperature; it is oxidized to tungsten oxide when heated in air.