Characterization and solid particle erosion behavior of plasma sprayed alumina and calcia-stabilized zirconia coatings on Al-6061 substrate

► Thermal stresses developed during spraying were main causes for presence of micro-cracks in the coatings. ► For the highest adhesion values, coating failure was mainly located in the bond coat/substrate interface. ► Erosion wear was more at 45° angle of impact showing that erosion behavior as a composite ductile–brittle. ► Erosion of coating systems occurred through spalling of lamella exposed on coating surface resulting from cracking along the lamellar interface. Repeated impact by solid particles causes erosion and degradation of engineering components. In internal combustion engines, during combustion, hot gases are generated in large quantity which causes erosion of cylinder, combustion chamber, exhaust system, etc. In this work, two types of plasma sprayed coating systems were developed on Al-6061 substrate. For each system, a systematic microstructural study was carried out to understand changes occurred after spraying. Mechanical properties like density, adhesion strength and hardness of coatings were determined. A solid particle erosion test was conducted on coating systems according to ASTM G-76-02 and results were correlated with the microstructural and subsequent mechanical property change. It was observed that volume erosion is more at 45° angle of impact and shows that behavior is in between ductile and brittle. This work also discusses the mechanism involved in erosion wear of plasma sprayed coating systems.