Influence of Secondary Ceramic Additives on the Tribological Performance of Plasma Sprayed Cr2O3 Composite Coating
摘要
For applications demanding low friction and improved wear resistant characteristics, Cr2O3 ceramic coatings developed through plasma spray are widely being employed. However, the ever-increasing demand for reduced friction and increased wear resistance necessitates the exploration of modified coating composition. In this study, Cr2O3 alloyed with Al2O3 and MoO3 individually and were sprayed onto T91 boiler grade steel using air plasma spray (APS). It was found that the addition of Al2O3 and MoO3 doesn't significantly enhance the hardness, however Cr2O3-Al2O3 coating exhibited higher friction coefficient (0.65), whereas, MoO3 addition resulted in lower coefficient of friction (0.45) compared to pure Cr2O3 (0.55). During ball-on-disc sliding wear tests, the Cr2O3-Al2O3 coating exhibited deep wear tracks with bulk material removal, whereas Cr2O3-MoO3 coating benefited from MoO3's soft and non-abrasive nature. The so-formed fine wear debris was found to get entrapped and subsequently undergo compaction and adhere well onto the surface, forming a cohesive film. It can be concluded that that the tribological performance of the Cr2O3 based composite coatings is significantly influenced by its hardness and lubricating characteristics of additives.