Improvement of wear and corrosion resistance by cold spray coating on W43 magnesium alloy

Magnesium and its alloys are classified as light metals due to their low densities and are preferred in a lot of applications thanks to their high specific strengths. It is used in biomaterial applications, structural applications, automotive and aerospace applications. However, the wear and corrosion resistance of these alloys is insufficient for some applications and needs to be improved. In environments containing chlorine and fluorine ions at high ion concentrations, magnesium and its alloys dissolve and cannot maintain their mechanical integrity. Within the scope of the thesis study, cold spray coatings were carried out using two different WE43 Mg alloy surface parameters, which were sandblasted using S330 steel balls and roughened by sanding, using K-32 powders containing Ni and Al2O3, and K-714 coded powders containing Zn, Ni, and Al2O3. The powders used for the construction of the coatings were sprayed onto the alloy surfaces using three different temperature parameters, 400, 500, and 600 °C. The surface and cross-section morphologies of the coated samples were evaluated, and their mechanical properties were examined. The applied coatings were compared among themselves in terms of wear and corrosion resistance, with uncoated WE43 and with the studies in the literature. As a result of the study, the coating thicknesses were obtained in the range of 6.83 µm and 11.1 µm for the samples, which were homogeneously deposited on the surface and coated using K-32. In the samples coated with K-714, the lowest coating thickness was measured as 34.73 µm and the highest obtained coating thickness was 87.7 µm. The sandblasting process increased the surface roughness and coating thickness, and the increase in the used gas temperature increased the deposition efficiency. Thanks to the deformation facilitated by the increase in temperature, the particles adhered to the substrate surface and each other more easily, the scattering decreased and the coating thickness increased. The wear and corrosion resistance of the samples, which were coated at 600 °C temperatures, where the deposition efficiency is the highest, were determined as the best samples.