In situ high temperature x-ray diffraction study on tungsten carbide formation

In-situ high temperature x-ray diffraction (HT-XRD) was used to measure carburization processes of tungsten/carbon mixtures. The high time resolution (2-5 min/scan) of the experimental setup enables the observation of any state of the carburization. We discuss the influence of different experimental parameters on the carburization process: sample preparation parameter (milling intensity); particle size and morphology of the carbon black powders; impurities in the W and C mixture. We propose phase transition mechanisms resulting from the evaluation of the isochronal XRD-pattern. The effect of grain growth inhibitors on the rate of the W{sub 2}C-transformation was measured in dependence of the grain growth inhibitor concentration (e.g. Cr{sub 3}C{sub 2}). The grain size and the grain size distribution of the resulting tungsten carbide was determined by scanning electron microscopy. (author)