Research on Microstructure and Mechanical Behavior of Nanostructured WC-17Co HVOF Coatings

Conventional,ultra-fine and nanostructured WC-Co coatings are obtained by means of the high velo-city oxygen flame(HVOF) technique.The microstructure of the powders and coatings are analyzed.The phases of the powders and coatings are analyzed too.The microhardness,Young′s modulus and fracture toughness are compared too.The results show that there forms nano-sized cell structure,lath structure and amorphous structure in nanostructured WC-17Co coatings.The coating structures are dense,which are formed of the re-crystallized zone,partially melted zone and non-melted zone.The lamellar structure of the coatings is not obvious which is different from the APS coatings.The nanostructured coatings are more denser and the carbide particles distribution is more even.The WC is the main phase and W2C,Co6W6C are little.The mocrohardness,Young′s modulus,and fracture toughness are best in the three kinds of coatings.