Microstructure and Properties of Cold-Sprayed Al-x%Al2O3 Composite Coatings on LA43M Mg-Li Alloy.

Al-x%Al2O3 composite protective coatings were prepared on the surface of LA43M Mg-Li alloy substrate by cold-spraying technology. The microstructure, corrosion resistance, tribological properties of the coatings were investigated in detail. The results showed that the addition of hard Al2O3 particles was conducive to the deposition of Al-based coating, and the bonding mode between Al-x%Al2O3 coating and substrate was metallurgical bonding and mechanical interlocking. Moreover, the addition of Al2O3 particles was beneficial for increasing the density of the coating, and significantly improving the corrosion resistance, hardness and tribological properties of composite coatings. Respecting the corrosion resistance of Al-x%Al2O3 composite coatings, the electrode potential of coatings increased significantly and stabilized to about − 1.0 V when the additive amount of Al2O3 increased to 10-25%, while the corrosion current density decreased to about 10-8 A/cm2, which was four orders of magnitude lower than that of LA43M Mg-Li alloy substrate. On the other hand, the tribological properties of Al- x%Al2O3 composite coatings were improved with the additive amount of Al2O3 phase increased. When the additive amount of Al2O3 increased to 15-25%, the coefficient of friction was stable at about 0.45 and the wear rate decreased. [ABSTRACT FROM AUTHOR]