COMPOSITIONAL MODIFICATION OF TITANIUM CARBIDE POWDERS BY INDUCTION PLASMA TREATMENT

Non-stoichiometric titanium carbide powders were treated in an r.f. induction plasma. The composition of plasma gas, reactor pressure and powder feed rate were changed as experimental parameters, but plate power was kept constant. As the titanium carbide powders passed through the plasma, they melted, partially evaporated, and finally solidified. During the in-flight process, compositional modification was noted involving lattice modification and a change of the non-stoichiometry of titanium carbide depending on the plasma and powder feeding conditions. These were mostly due to the removal of carbon and oxygen impurity in titanium carbide while melting. The mu-AES analysis indicated that the removal of carbon occurred in the plasma treatment. The deposits formed from the vapour phase consisted mainly of very fine cubic crystals, some tens of nanometres in size, with an appreciable number of vacancies at carbon sites.