Microstructure, wear and mechanical properties of plasma sprayed TiO2 coating on Al–SiC metal matrix composite

Abstract

In the present study, the hard TiO2 coating was plasma sprayed on the Al/SiC composite substrate. The coating was characterised for microstructure, mechanical and tribological properties and compared with the substrate. The key findings from the present study are: (1) The lamellae structure of the coating contains semi and fully melted particles, round porosity without any evidence of spallation or delamination or un-melted particles and non-stoichiometric and oxygen deficient phases and shorter stand-off distance would be a probable reason for the occurrence of partial melted regions and porosity in the coating, (2) The coating has improved significantly scratch resistance, hardness, fracture roughness, friction coefficient and wear resistance of the substrate, and (3) mild abrasive wear is responsible for low wear loss in the coated sample whereas the combination of severe delamination wear and abrasive wear causes the considerable wear loss in the uncoated sample.