Regularities of reactions of titanium carbonitrides and oxycarbides with nickel

Resumo

Specific features and regularities of reactions of titanium carbide alloyed over the sublattice of nonmetals (N, O) with the nickel melt are analyzed. It is established that the partial substitution of carbon in TiC by nitrogen decreases its dissolution rate in nickel and increases the degree of process incongruence (the transfer of carbon into the melt is preferential compared with titanium). The concentration dependence of the dissolution rate of TiC_xN_z in nickel changes its sign to the opposite one compared with approaching the system to equilibrium. Titanium carbonitride is not recrystallized through the nickel solution as the only phase, and mainly its carbide component is subjected to recrystallization. It is revealed that the partial substitution of carbon in TiC to oxygen increases its dissolution rate in nickel. The dissolution of oxycarbide TiC_0.6O_0.4 in nickel is accompanied by the gradual loss of its carbon until titanium monoxide is formed and by its further disproportionation. The peculiarity of the interaction mechanism of titanium oxycarbides with the nickel melt is determined by reaction [C] + [O] = CO↑ in the liquid phase.