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, which has 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°C to produce a hardness alloy Patents.