Pseudopartial wetting of WC/WC grain boundaries in cemented carbides

WC–Co cemented carbides are metal–ceramic composites consisting of a ceramic phase, tungsten carbide, and a cobalt binder. The key to the exceptional properties of cemented carbides is the optimal combination of hardness and wear-resistance of WC grains, and toughness and ductility of the Co-based matrix. However, only the minority of WC/WC GBs are completely wetted by Co melt during the liquid phase sintering. We observed for the first time that other WC/WC GBs are not partially wetted and, therefore, “dry”. They are pseudopartially wetted, namely they have the high contact angle with cobalt binder and, nevertheless, contain the 2–3 nm thin uniform Co-rich layer.