WO<SUB>3</SUB>-C-Co<SUB>3</SUB>O<SUB>4</SUB>を直接炭化した粉末から作製したWC-Co合金の性質

Abstract

WC-(1∼6%)Co mixed powders obtained from the mixtures of WO3, C and Co3O4 were sintered. The mixed powders in which the Co content was adjusted by addition of Co powder were also sintered. The relation between the Co content of the starting powders and the WC grain size of the alloy was studied in comparison with usual alloys which was obtained from WC and Co powders. The following results are obtained.(1) The starting powders containing more than 3% of Co could be sintered to the alloy having the full density and good strength without further addition of Co.(2) The WC grain size of alloys depends on the Co content of the starting powder and the size was smaller with increasing Co content. Even in the alloys sintered at high temperature where grain growth of the carbide was observed, each WC grain size was uniform compared to usual WC-Co alloys sintered at the same temperature. The coarsening caused by the sintering decreased with increasing Co content of the starting powder.(3) We found that the grain growth and hardness drop of alloys obtained from directly carburized powders were small even at high temperature sitering, compared to usual WC-Co alloy. Therefore, the temperature range suitable for the sintering is wider than that for usual WC-Co alloys.