Formation of ternary carbide Co6W6C by mechanical activation assisted solid-state reaction

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, Co6W6C, 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 Co6W6C, Co2W4C and Co3W9C4, 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 Co6W6C 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.