AZ31镁合金冷喷涂Al-Al_2O_3复合涂层组织及性能

Microstructure and properties of cold sprayed Al-Al_2O_3 coating on AZ31 magnesium alloy

采用冷喷涂工艺在AZ31镁合金上制备纯Al涂层和Al-50%Al_2O_3复合涂层。通过扫描电镜(SEM)、能谱仪(EDS)、材料分析软件探讨Al_2O_3颗粒的加入对纯Al涂层显微组织的影响。用电化学工作站、显微硬度计和磨耗试验机来对涂层的性能进行表征,分析Al_2O_3颗粒的加入对纯Al涂层耐蚀性、显微硬度和磨损性能的影响。结果表明:与纯Al涂层相比,复合涂层组织更致密,孔隙率更低,硬度从51.2HV0.025提高到94.8HV0.025,滑动磨损率降低80.5%,磨粒磨损率降低40%。复合涂层的自腐蚀电流密度(2.36×10^(-7)A/cm^2)和纯Al涂层的自腐蚀电流密度(1.19×10^(-7) A/cm^2)相近,相对于镁合金的(2.56×10^(-4) A/cm^2)降低3个数量级,可以大大提高镁合金的抗腐蚀性能。

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.