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The powder mixtures of Co/W/C=6/6/1–1/1/2 in molar ratio were mechanically activated by grinding in a planetary ball mill and subsequently heated at 800–1100 °C in argon atmosphere. Ternary carbide, Co 6 W 6 C, was obtained from the sample of Co/W/C=7/7/2 which was ground for 4 h and heated at 1100 °C. In contrast, from most of the samples ground for 1–3 h, WC was mainly formed accompanying Co 6 W 6 C, Co 2 W 4 C and Co 3 W 9 C 4 , and from the unground samples, these carbides were hardly formed. From the results concerning the effects of mixing ratio, grinding time and heating temperature of the Co/W/C powder mixtures on the formation of ternary carbides, it was found that the formation of Co 6 W 6 C strongly depends on the mixing homogeneity, the intimate contact and the activated state of the Co, W and C grains, finely ground by ball milling. |
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