The relationship between Vickers' microhardness and non-stoichiometric composition of titanium carbide (TiCx) plates was investigated. TiCx plates having a composition range from x = 0.57 to 1.0 were prepared by chemical vapour deposition using TiCl4, CCl4 and H2 as source gases at total gas pressures (Ptot) of 4 and 40 kPa and deposition temperatures (Tdep) of 1573 to 1873 K. The microhardness increased from about 2000 to 3000 kg mm-2 with increasing x independent of Tdep, but this change depended on Ptot. The TiCx plates prepared at Ptot = 4 kPa showed slightly higher hardness values than those prepared at Ptot = 40 kPa. The relationship between Ptot and microhardness was explained by the difference in grain sizes. The grain sizes of deposits prepared at Ptot = 4kPa were about half the size of those prepared at Ptot = 40 kPa.
ASJC Scopus subject areas