Tungsten Carbide Button Physical Properties
Introduction
Tungsten carbide button is a metal part of which main components are refractory metal with high hardness（WC, TiC）and micron powder and its binder are Co, Ni, or Mo. It is the powder metallurgy product which is sintered in a vacuum furnace or a reduction furnace. The production method is powder metallurgy, including sintering and hydrogen reducing. Carbides, nitrides, borides etc. of the IVB, VB, and VIB metals are collectively referred to as carbides because of their particularly high hardness and melting point.
Properties
The constituent elements of this product in the IVB, VB and VIB belong to the metal-type carbide formed by metal and carbon. The radius of carbon atom is so short that it can fill the gap of metal lattice and keep the original form of lattice to form interstitial solid solution. Under the appropriate condition, the interstitial solution can continue dissolving its constituent elements until it is saturated. When the amount of dissolved carbon exceeds a certain limit, the lattice pattern will change, transforming the original metal lattice into another form of it. The interstitial solid solution is called interstitial compound. In addition to carbon atoms in the tungsten carbide, nitrogen atoms and boron atoms can also enter into the voids of the metal lattice to form the interstitial solid solution. Their properties to the properties of interstitial carbides. They can conduct the electricity and heat. They have high melting point, hardness and brittleness. Besides, nitrides, boride and silicide of transition metals also have similar properties which can replace the hardening phase of tungsten carbide button. The high hardness and durability of this product depends on the hardening phase.
The melting point of metal carbide of tungsten carbide button particularly in IVB, VB and VIB is higher than 3273K. Most of carbide has high hardness. Their microhardness is higher than 188kg/mm2. (Microhardness is one of the hardness representation, equivalent to Mohs-diamond-hardness 9.) A lot of carbide is difficult to be decomposed at high temperature. Their anti-oxidant capability is better than other constituent metals. However, in an oxidizing atmosphere, a lot of carbides are easily oxidized at high temperatures, which is a major weakness of carbides.