Sliding wear characterization of microwave-glazed plasma-sprayed ceramic composites

Abstract

The main objective of the present study is to present the wear characteristics of postprocessed plasma deposits of alumina-titania (AT-13) ceramic composites under high-speed sliding. Spray deposits were post-processed (microwave glazed) by way of exposing them to microwave radiation at a frequency of 2.45 GHz in a multi-mode cavity by using the microwave hybrid heating principle. During 'microwave glazing', densification of the coating's structure takes place as a consequence of microwave-heating-induced phase transformation, leading to significant enhancement in hardness and reduction in porosity. Responses of the as-sprayed and microwave-glazed composites were monitored while they were subjected to sliding type of tribocontact at a speed of 5 m/s. Subsequent analyses are presented in terms of wear rate, pressure-velocity-time (p-v-t) characteristics, fractography, elemental count, and acoustic emission (AE) emanated during the trials. The results show a steady sliding wear response after an initial higher rate. The p-v-t factor analysis confirms a better operating condition with glazed composites. Glazed composites exhibit higher stability towards elemental transfer between the wear surface and the counter surface. AEs emanating during trials indicate deformation and brittle fracture as the dominating wear mechanisms of the as-sprayed and microwave-glazed ceramic composites.