Effect of feedstock size on the properties of WC-17Co coatings

Abstract:

High velocity oxy-fuel (HVOF) spray technique has been utilized to fabricate WC-17Co cermet coatings. To achieve a high performance of mechanical properties and abrasive wear resistance, four types of WC-17Co powders with different feedstock particle size were investigated. The results show that the feedstock powder with finer particle size had higher velocity and temperature during spraying process, resulting in a denser coating and a stronger splat-splat bonding. It was found that the micro-hardness of WC-17Co coating increased with the decreasing of feedstock size. The coating deposited by finer feedstock powder had superior abrasive wear resistance, attributing to the smaller porosity and boundary flaws on coating. However, coating fracture toughness could be affected by feedstock size if it is too small. Among all those investigated, the one with medium particle size and narrow size distribution exhibited both excellent mechanical properties and wear resistance.