Effects of powder characteristics and high velocity flame spray processes on Cr3C2-NiCr-coatings

Wear protection is one of the major applications of thermally sprayed hard metal coatings. This paper presents the latest results of a systematic study on the influence of Cr3C2-NiCr feedstock powder characteristics on coating microstructures and economic parameters like deposition rate and deposition efficiency. Four commercial Cr3C2-NiCr powders with spherically shaped particles but different structural features were characterized and deposited by a liquid-fueled and a gas fueled HVOF and a HVAF process. Deposition rates and efficiencies were determined; all coatings were analyzed in as-sprayed condition and selected samples were heat-treated at 800 °C in argon atmosphere. The effects of the feedstock powders and spray processes on the coating characteristics (microstructure, hardness, Young's modulus and diffusion processes during heat treatment) were studied.