Microstructure and properties of cold sprayed Al-Al2O3 coating on AZ31 magnesium alloy

The pure Al coating and Al-50% Al2O3 composite coating were deposited on AZ31 magnesium alloy by cold spraying. The effect of addition Al2O3 particles on morphology of the pure Al coating was analyzed by scanning electron microscopes(SEM), energy dispersive spectroscopy(EDS) and material analysis software. The effects of Al2O3 particles adding on corrosion resistance, micro-hardness and wear properties of the pure Al coating were studied by using electrochemical workstation, microhardness tester, abrasion tester to evaluate the properties of coatings. The results show that the composite coating possessed higher density, lower porosity, the microhardness increases from 51.2 HV0.025 to 94.8 HV0.025, the sliding wear rate decreases by 80.5% and the abrasive wear rate reduces by 40% in comparison to the pure Al coating. The corrosion current densities of the composite coating (2.36×10-7 A/cm2) and the pure Al coating(1.19×10-7 A/cm2) show the same level, but they are about 3 orders of magnitudes low compared with that of magnesium alloys substrate(2.56×10-4 A/cm2), which can significantly improve the corrosion resistance of magnesium alloys. © 2018, Science Press. All right reserved.