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【Chinatungsten Online News Net- Tungsten News】

There are two well characterized compounds of tungsten and carbon, WC and W2C. Both compounds may be present in coatings and the proportions can depend on the coating method.

WC can be prepared by reaction of tungsten metal and carbon at 1400–2000 °C

* tungsten hexachloride with hydrogen, as reducing agent and methane as the source of carbon at convert|670|°C|F:WCl6 + H2 + CH4 → WC + 6HCl

* reacting tungsten hexafluoride with hydrogen as reducing agent and methanol as source of carbon at convert|350|°C|F:WF6 + H2 + CH3OH → WC + 6HF + H2O

* At high temperatures WC decomposes to tungsten and carbon and this can occur during high temperature thermal spray, e.g. high velocity oxygen fuel (HVOF) and high energy plasma (HEP) methods.

* Oxidation of WC starts at 500–600 °C. It is resistant to acids and is only attacked by hydrofluoric acid/nitric acid (HF/HNO3) mixtures above room temperature. It reacts with fluorine gas at room temperature and chlorine above convert|400|°C|F and is unreactive to dry H2 up to its melting point.

WC has been investigated for its potential use as a catalyst and it has been found to resemble platinum in its catalysis the production of water from hydrogen and oxygen at room temperature, the reduction of tungsten trioxide by hydrogen in the presence of water, and the isomerization of 2,2-dimethylpropane to 2-methylbutane.