Microstructure and properties of SHVOF and SPS-sprayed Cr2O3 coatings

Chromium oxide (Cr2O3) is commonly used as an atmospheric plasma-sprayed (APS) coating from powder feedstock in applications requiring resistance to sliding wear and corrosion, as well as amenability to texturing e.g., in anilox rolls. Recently, high-velocity oxy-fuel and plasma spray methods involving suspension feedstocks have been considered an extremely promising alternative to produce more dense and homogeneous chromium oxide coatings with lower as-sprayed surface roughness, higher hardness and potentially superior wear performance compared to conventional APS sprayed coatings. In this study, suspension high-velocity oxy-fuel (SHVOF) spraying and suspension plasma spraying (SPS) of identical Cr2O3 suspensions is presented. The coatings produced by both the above routes have been comprehensively characterized for their microstructure, mechanical properties and wear resistance by cavitation erosion. The prominent results ensuing from the above will be discussed and some insights into process parameter impact on characteristics of the suspension-sprayed coatings also provided.