Effect of high-enthalpy atmospheric plasma spraying parameters on the mechanical and wear resistant properties of alumina ceramic coatings

Over the past decade, alumina ceramic coatings have become promising candidates for anti-wear and anticorrosion applications owing to their excellent mechanical properties, such as chemical inertness and high temperature resistance, high hardness, and high abrasion resistance. In this work, alumina ceramic coatings are prepared via high-enthalpy atmospheric plasma spraying. The effect of plasma spraying parameters should be paid to attention, such as spraying power, powder feeding rate, and initial substrate temperature, on the mechanical and wear characteristics of the obtained coatings. According to the results, the increase in the plasma spraying power allows one to substantially reduce the porosity of coatings and in turn improves the wear resistance. The use of the higher powder feeding rates enables one to achieve the lower density and adhesion of coatings, which is due to the rising amount of unmolten particles. Finally, an increase in the initial substrate temperature reduces to a large extent the defects of the coating by decreasing the quenching stress, which enhances their mechanical properties. A decrease in the porosity of the coating is beneficial to improve the wear resistance.