Effects of Laser-Remelting on the Microstructure, Hardness and Oscillating Wear Resistance of Atmospheric Plasma Sprayed Alumina-Rich Coatings
Thermally sprayed ceramic coatings such as alumina have a specific microstructure characterized by porosity and microcracks. In addition, a process-related phase transformation from α-Al2O3 to γ-Al2O3 typically occurs, which affects the properties of the coatings compared to sintered alumina. In a previous study, simultaneous additions of Cr2O3 and TiO2 have already extended and improved the property profile of pure alumina coating (i.e., sliding wear resistance and corrosion resistance against
... 1N H2SO4). Depending on the powder material used, the phase composition of the coatings differs considerably, influencing the property profile. Chemical integration through reactive bonding promises a previously untapped potential for improvement. In this study, these alumina-rich ternary oxide coatings are remelted by laser, and the effect of different parameters such as speed, laser power or distance on the macro- and microstructure of the coatings is investigated. For this purpose, both light microscopic and SEM examinations are used as well as the determination of the phase composition by XRD and element distribution by EDS. The created coating microstructures are studied with respect to hardness and oscillation wear resistance.