P. Chivavibul, National Institute for Materials Science, Ibaraki-ken, Japan; M. Watanabe, S. Kuroda, National Institute for Materials Science (NIMS), Tsukuba, Japan
Twelve commercially available WC-Co powders with different average carbide sizes (0.2, 2, and 6 mm) and cobalt contents (8, 12, 17 and 25 wt.%) were sprayed on carbon steel substrates using High Velocity Oxy-Fuel (HVOF) process. Characterization of the coating showed that the average carbide sizes were smaller than those of feedstock powders. Hardness, Young’s modulus, and Fracture toughness of the coatings were investigated using indentation techniques. The hardness and Young’s modulus decreased with increasing cobalt content, while fracture toughness slightly increased. These behaviors were discussed with the help of microstructure parameters of the coatings such as carbide volume fraction, carbide size, and mean free path of binder. The relation of mechanical properties and microstructure parameters was obtained.
