High-carbon-side Boundary of δ-TiC_xO_y Phase in the Low-Oxygen-region of Ti-C-O System

Abstract

To determine the solubility of C in δ-TiC_xO_y especially in the vicinity of the TiC_{1, 0} composition, the partial isothermal phase diagram of Ti-C-O system, indicating a high C side boundary of δ-TiC_xO_y phase in the low-oxygen region at 1473 K, was constructed from the chemical analyses of thoroughly equilibrated specimens which had been held for long time at various temperatures under various CO pressures, followed by vacuum heat-treatment (annealing) at 1473 K for 3 Ms.
The solubility of C in δ-TiC_xO_y was decreased markedly by the existence of small amounts of Oxygen especially in the cases of ≤0.7 at%O. When O≤0.02 at%, the solubility of C was ≥49.8 at%, and tended to increase toward 50 at% at the limiting condition of Oxygen→O%.