Fine platelet-like grained WC–Co cemented carbides: Preparation, characterization, properties and application in PVD coating substrates

Abstract

Strengthening of the adhesion strength and its stability of PVD coated cemented carbides has always been the focus of attention. Commercial ultrafine WC–12Co composite powder by spray conversion processing was used as the raw material. WC–12Co–0.05La2O3, WC–12Co–0.9Cr3C2–0.05La2O3, WC–12Co–0.5Cr3C2–0.4VC–0.05La2O3 and WC–12Co–0.9Cr3C2–0.4VC–0.05La2O3 alloys were prepared by a conventional long-time ball-milling. The results show that fine platelet-like grained WC–12Co–0.9Cr3C2–0.4VC–0.05La2O3 alloy is characterized with a homogenous microstructure, the best property combination of high strength, high hardness and high toughness and the highest WC (0001) texture coefficient. By using fine platelet-like grained WC–Co cemented carbides as the substrates, larger than 100N adhesion strength expressed by critical load LC2 for AlCrN, AlTiN and (AlCrSiWN+AlCrN) PVD coatings is achieved. The related strengthening mechanisms are discussed.