Carbide

After tungsten carbide, titanium carbide, TiC, is the most important metallic hard material. It is manufactured from pure TiO₂ and carbon black in induction furnaces at 2000 to 2200°C:

TiC is also produced in small quantities from titanium scrap in nickel and iron baths using the menstruum process.

Titanium carbide has the highest hardness of all metal carbides, but is rarely used on its own in cemented carbide technology, since the high oxygen content of the titanium carbide makes the hard metal too brittle. It is thus mainly utilized in the manufacture of mixed crystals such as (Ti,W)C, (Ti,Ta,W)C and (Ti,Ta,Nb,W)C for hard metals.

One possibility of exploiting the hardness of pure TiC is by coating cemented carbides. Thin layers (5 to 8 μm) of TiC of Ti(C,N) can be deposited using the CVD process by thermal decomposition -of titanium tetrachloride in a methane / hydrogen atmosphere.

Carbide and Carbide

, ZrC, and hafnium carbide, HfC, can be manufactured in a similar way to titanium carbide. They are not very important in cemented carbide technology. The recent strong reduction in the price of HfC has enabled its application as a substitute for the dearer tantalum carbide.