Microstructure of plasma sprayed composite ceramic coatings on magnalium alloy

In this paper,to solve the problem of poor wear resistance of magnalium alloy,the composite ceramic coating on XGFH-3 magnalium substrate was prepared by plasma spraying by using composite ceramic powder as raw materials, which were made by mechanical ball milling and PVA granulating technology. The microstructure and phase composition of the composite ceramic powders and coatings were characterized by SEM and XRD. The results show that the composite ceramic powders become remarkably flattened and homogenized with increasing milling time and new phases such as Al₃Ti and Ni₄Ti₃ are formed. However,in the spraying process,Al₃Ti and Ni₄Ti₃ intermediate phases disappear and new phases such as MgAl₂O₄ and Ti₅Si₃ are formed in the coating. There is elements diffusion between the substrate and the coating,resulting in strong bonding strength of the coating.