Abstract
The high temperature oxidation tests for WC-14-Co alloy containing nitrogen, i.e., WC-β(N)-Co alloy (β: WC-TiC, β(N): WC-TiC-TiN solid solution) were made in air at 973-1173K and the results were compared with those of WC-Co, WC-β-Co, WC-β-TaC-Co alloys, etc.
The oxidation resistance of WC-fl-Co alloy was remarkably improved by the nitrogen addition. The beneficial effect of TaC addition on the resistance was confirmed. The oxidation of cemented carbides was found in common to be controlled by the reaction at the interface between oxide layer and alloy matrix. The improvement in oxidation resistance of the alloys containing nitrogen or TaC would be understood in view of the fact that β(N) or triple carbide particles, being considered to act as obstacles to the diffusion of oxygen, inclined to remain unoxidized in the scale near the interface.
