Volume 11 Issue 3 ( September 2024)

In this work an investigation has been done on four samples of magnesium alloy AZ31 coated with a different percentage mixture of Al₂O₃ and TiO₂ particles by plasma spray method. The effect of the existence of ceramic particles on the surface of AZ31 substrate was studied. A homogeneous distributed microstructure of coated surface was brought to light in microscopy analysis. Densification of the surface was reported with an increasing percentage of TiO₂ content. The nanoindentation study showed that the hardness of coated surface is inversely proportional to TiO₂ percentage. XRD analysis was done, and the results of hardness tests were correlated with SEM and XRD analysis. It was observed that, increase in percentage of TiO₂ beyond 20% led to the formation of Aluminium titanate (Al₂TiO₅) as major phase in coating. Further, decreased densification and increased porosity level were observed due to formation of microcracks with this phase formation. Better densification of coating on AZ31 with less porosity was observed with addition of 20% of TiO₂ particles in Alumina. Increased percentage of TiO₂ beyond 20% decreased the coating hardness by 7%. Fabricated material can be used in places where strength to weight ratio plays an important role. Hence it may be useful in automobile and aircraft parts.

Keywords: AZ31 Mg Alloy, Plasma Spray coating, Hardness, Al₂O₃, TiO₂