Abstract:In order to improve the properties of the nanostructured Al2O3-13wt%TiO2 composite ceramic coatings fabricated by plasma spraying, a laser remelting experiment was carried out and the effects of laser remelting on the microstructure and properties of coatings were studied. The morphology, microstructure and microhardness of the coatings were investigated by SEM and microhardness. Meanwhile, the wear behavior of the coatings was researched. The results show that the plasma-sprayed nanostructured ceramic coating consists of not only fully melted regions but also partially melted regions, and the total coating has a lamellar-like structure as conventional coating. According to the microstructural difference, the ceramic coating can be divided into the remelted zone (fine equiaxed grains), the sintered zone and remained plasma-sprayed zone after laser remelting. The surface ceramic coating has smaller grains and higher compactness, and the lamellar structure of plasma-sprayed coating is eliminated. Due to the rapid heating and cooling of laser remelting, there are still some nanoparticles coming from the remained nanoparticles of plasma spraying in the remelted zone. The nanostructured ceramic coating has higher hardness, better wear resistance than the conventional ceramic coatings, and the laser–remelted coating has the highest hardness and the best wear resistance