Influence of Cr3C2-NiCr feedstock powder characteristics on the deposition efficiency, coating microstructures and abrasion wear resistance

Wear protection is one of the most important applications for thermal spray hardmetal coating solutions. For this purpose, including high temperature applications, hardmetal coatings based on WC and Cr 3C 2 with metallic binders (Co, Ni or NiCr) and deposited by high velocity flame spraying processes (HVOF/HVAF) are widely used. There are both technical (improving coating performance) and economical challenges (lower the coating costs, e.g. by increasing the deposition efficiency (DE)) which have to be solved for future applications. In this contribution first results of a systematic study on the influence of Cr3C2-NiCr feedstock powder characteristics on the deposition efficiency, coating microstructures and tribological properties are published. Four commercial Cr 3C 2-NiCr feedstock powders with different microstructural features were thoroughly characterised and sprayed with a liquid-fuelled HVOF process. The deposition efficiency was measured and the coating microstructure, hardness, Young's modulus, and abrasion wear resistance were studied. Changes of microstructure and coating hardness occuring in result of a heat treatment at 800 °C in inert atmosphere are reported.