Abstract
The titanium carbide solid solution (δ-phase)in Ti-C-Co system was compared with the sintered alloy from the view-point of oxidation resistance. The δ-phase alloy containing about 14.5%C and 4%Co was prepared by arc-melting in argon atmosphere. The sintered alloy containing about 14.5%C and 14%Co was prepared in argon atmosphere at 1380°C. Oxidation tests were carried out in dry oxygen at 1 atm. pressure at 750°C and 900°C. The amount of oxidation was measured with a quarz spring balance and the weight change of absorbent of CO2 generated from the specimen during the oxidation. The oxides were examined by X-ray analysis and microscopic observation. Most of the specimens nearly follow the parabolic rate law in oxidation. There is no great difference in the weight gain during oxidation between δ-phase alloy and sintered alloy. Oxides formed in these conditions are mixtures of CoO and TiO2 (rutile). The preferred oxidation of the intergranular part in sintered alloy and of δ-phase boundary occurs at early stage of oxidation.
