Tungsten Carbide Brief Introduction

There are three main compounds of binary tungsten-carbon system:
Tungsten monocarbide (WC)（shown as FIGUE.1）, is the main constituent in most of the commercial cemented carbides, also commonly defined as tungsten carbide, is the only stable tungsten carbide at room temperature.  
Ditungsten carbide (W₂C), can be used as a hard material.
Nonstoichiometric tungsten carbide (WC_1-x), is an cubic high-temperature modification, which undergoes a eutectoid decomposition at 2530-2535℃ into β（W2C）+δ（WC）.At room temperature it can only be obtained by rapid quenching in liquid tin.

Tungsten carbide have such advantages as follow:
1.High melting point and boiling point, the melting point of tungsten carbide is 2870℃ and the boiling point is 6000℃ under atmospheric pressure。
2.High hardness, tungsten carbide is a common hard phase of cememted carbide.
3.High density, the density of tungsten carbide is 15.63g/cm3.

High thermal expansion coefficient, the thermal expansion coefficient of tungsten carbide is 6.9×10-6/K.
4.High elastic modulus, the elastic modulus of tungsten carbide is 5 times than steel's.
Tungsten carbide powder is synthesized by tungsten powder and carbon black in a high frequency induction furnace or Carbon tube furnace at high temperature with or without hydrogen gas. Under hydrogen atmosphere, the carbonation reaction happened between tungsten and methane which is synthesized by carbon and hydrogen, otherwise the reaction will happened directly between tungsten and carbide.

Tungsten carbide have such applications as follow:
1.It is a common hard phase in cememted carbide;
2.Tungsten carbide is used as a raw material of compound carbide;
3.Tungsten carbide can apply as catalyst in organic chemistry and electrochemistry as catalyst.
4.It used as surface strengthening material such as cast tungsten carbide  and surface spraying material. 

• < 前へ
• 次へ >