Binder-free WC bulk synthesized by spark plasma sintering

The spark plasma sintering (SPS) behavior of binder-free WC was investigated by a series of experiments. The appropriate contents of carbon addition to form dominant WC phase were determined corresponding to different sintering parameters. By optimizing the processing parameters, with 0.1 wt% carbon addition and sintered at 1460 degrees C, the WC cemented carbides of high density and a fine microstructure with grain sizes less than 350 nm were obtained. By means of TEM and high-resolution transmission electron microscope (HRTEM) observations, the clean WC grain boundaries were found, and the orientation relationship between neighbouring WC grains was studied. The advantages, as well as the mechanisms of SPS sintering binder-free WC, were also discussed. (C) 2008 Elsevier B.V. All rights reserved.