Sliding wear behavior of in-situ FeAl2O4 matrix nanocomposite coating fabricated by plasma spraying

FeAl2O4 matrix nanocomposite coating was successfully developed by plasma spraying Al/Fe2O3 composite powders. The microstructure of the coating was characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, respectively. The results indicated that the as-prepared coating exhibited dense microstructure with nano-sized grains FeAl2O4 matrix and α-Fe and Al2O3 phases. The microhardness, toughness, and especially unlubricated sliding wear behavior of the composite coating were investigated. The toughness and sliding wear resistance of the composite coating were significantly enhanced despite its lower microhardness compared with the conventional alumina coating, which was attributed to the dense microstructure, the inclusion of ductile metallic phase in the composite coating, and the nanostructured microstructure of the composite coating. The worn surface of the alumina coating was characterized by intergranular fracture and interlayer fracture. The fracture of the composite coating was lower than that of the alumina coating. Intergranular fracture and interlayer fracture were dominated in the low load wear process of the composite coating. Adhesive wear was dominated in the high load wear process of the composite coating and accompanied by abrasive wear.