Effect of Microstructure of HVOF-Sprayed WC-Co Coatings on Their Mechanical Properties
Twelve commercially available WC-Co powders with different average carbide sizes (0.2, 2, and 6 μm) and cobalt contents (8, 12, 17 and 25 wt.％) were sprayed on carbon steel substrates using High Velocity Oxy-Fuel (HVOF) spraying Characterization of the coatings showed that the average carbide sizes and carbide volume contents in the coatings were lower than those of feedstock powders. Hardness and fracture toughness of the coatings were investigated using indentation techniques. Young’s modulus was measured by an ultrasonic technique. The hardness and Young’s modulus decreased with increasing cobalt content, while fracture toughness slightly increased. The effect of carbide size on the hardness showed no specific trend. These behaviors were discussed with help of microstructure observations of the coatings scanning electron microscopy, X-ray diffraction and chemical analysis. Using an improved HVOF process with a gas shroud could result in less decomposition of the powder and higher fracture toughness.
P. Chivavibul M. Watanabe S. Kuroda
National Institute for Materials Science, Tsukuba, Ibaraki, Japan
国际会议
北京
英文
2007-05-14（万方平台首次上网日期，不代表论文的发表时间）