Abrasion Wear Behaviour of Plasma and HVOF Sprayed Al₂O₃ SiC Nanocomposite Coatings

The present work describes abrasion wear tests that were carried out on low carbon steel test wheels coated with a series of plasma sprayed and HVOF sprayed Al₂O₃-SiC coatings with varying SiC contents. These were compared to a pure Al₂O₃ coating applied by HVOF and to uncoated steel. The HVOF sprayed coatings exhibited consistently superior abrasion wear resistance compared to plasma sprayed coatings of equivalent composition and uncoated steel. Overall, the HVOF Al₂O₃-10%SiC nanocomposite coating showed the best abrasion resistance of all the coatings tested. They were worn very slowly by a micro-abrasion process. The poor performance of the plasma sprayed coatings was attributed to a low cohesive strength which made them particularly vulnerable to grain pull-out.