On the reaction sequence of WC–Co formation using an integrated mechanical and thermal activation process Original Research Article

A systematic study on the reaction sequence of WC–Co composite formation by annealing high energy ball milled WO3, CoO and graphite powder mixtures in a hydrogen atmosphere has been conducted. X-ray diffraction has been used as the main tool to analyze the phase transformation of the powder mixture during processing. It was observed that WO3 is reduced to W phase by passing through the intermediate W20O58 and WO2 phases and the subsequent carburization sequence appears as W→Co6W6C→Co3W3C→W2C→WC. The intermediate Co3W has been found in the reduction stage, which can be subsequently carburized at higher temperatures.