Many researchers have focused on the plasma-sprayed Al2O3- 13%TiO2 coatings and the effect of laser remelting on tribological property. Wang et al.reported that the laser remelting of plasma-sprayed Al2O3-13%TiO2 coatings on the Ti-6Al-4V alloy. It was shown that the laser remelting can be employed for the fabrication of dense Al2O3-13%TiO2 coatings and improve the hardness. Dubourg et al. studied properties of Al2O3–13%TiO2 coatings prepared by laser-assisted air plasma spraying and results showed that laser assistance may improve the microstructural and mechanical properties. Li et al. discussed the effects of feedstock preparation, plasma spraying and laser remelting process on the microstructure of the laserremelted Al2O3-13 wt%TiO2 coatings. Gao et al. indicated the interface characteristics of Al2O3–13%TiO2 ceramic coatings prepared by laser cladding and found that a two-layer substructure composed of fully melted layer and liquid-phase sintered layer exists in the ceramic coating. However, still now, few investigations were done on Al2O3-40%TiO2 coatings and whether the laser remelting can provide good tribological property should be studied further. In the present study, the Al2O3-40%TiO2 coatings were made by plasma spraying, then their surfaces were modified by laser remelting. And investigation is aimed at understanding the effect of laser remelting on the microstructure and erosion resistance of Al2O3-40%TiO2 plasma sprayed coating. In this work, Al2O3-40%TiO2 coating fabricated by plasma spraying were remelted by laser, and the effect of laser remelting on microstructure and wear resistance of plasma sprayed Al2O3-TiO2 coating were studied. (a) The plasma sprayed coating shows a lamellar-like structure and has a lot of pores and microcracks. Laser remelting can reduce the pores and microcracks and eras the lamellar defect. The microstructure of the coating becomes homogenous and compact. (b) The plasma sprayed coating consisted of α-Al2O3, γ-Al2O3 and TiAl2O5. After laser melting, metastable phase γ-Al2O3 transformed into stable phase α-Al2O3, and the composition of the coating becomes homogeneous. And the microhardness of the coating became more high and uniform.(c) Laser remelting can greatly improve the wear resistance of the plasma sprayed coating and the dominant wear mechanism for the laser-treated coating changed from spallation to microcrack and fracture wear.
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