Deposition and study of plasma sprayed Al2O3-TiO2 coatings on AZ31 magnesium alloy

Abstract

In this study, Al2O3, TiO2 and Al2O3+ 3wt%TiO2 coatings were deposited on AZ31 Mg alloy substrate by plasma spraying. The coatings were structurally characterized by scanning electron microscopy and X-ray diffraction. Corrosion experiments were carried out in 3.5% NaCl solution. Adhesion tests were performed according to daimler benz VDI-3198 standard. A coating layer of approximately 70 microns in thickness was deposited. High plasma enthalpy caused phase transformations in alumina-based ceramics. As a result of electrochemical corrosion study, it was determined that the coatings increased the corrosion resistance of AZ31 Mg alloy. While the most corrosion resistant coating is Al2O3+ 3wt%TiO2, the weakest coating against corrosion is TiO2. The adhesion behavior of all coatings to the substrate was at an acceptable quality levels.