KINETICS OF TITANIUM SUBOXIDE FORMATION IN THE CARBOTHERMAL REDUCTION OF THE DIOXIDE

Formation of TiC from mixtures of TiO2 and C does not occur at the temperature of the study (1010 less-than-or-equal-to T less-than-or-equal-to 1110-degrees-C). The first stage of the reaction, the reduction of the dioxide into several suboxides, is only observed at these temperatures. Two simultaneous reactions take place 1. The rate controlled decomposition of TiO2, such as 3 TiO2 --> Ti3O5 +1/2 O2 2. The formation of CO, in quasi-equilibrium, by: C + 1/2 O2 double-line arrow pointing left and right CO During the reaction appear the titanium suboxides TinO2n-1 (10 less-than-or-equal-to n less-than-or-equal-to 3). Inside of them occurs oxygen diffusion that is the limiting step of the reaction. The addition of carbon monoxide slows down the rate of the reaction and the noticed linkage between temperature and P(CO) prevents any analytical development. In some cases (P(CO) = 5.103 Pa and T less-than-or-equal-to 1030-degrees-C), the final product of the reaction is Ti4O7.