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为提高AZ31B镁合金表面的耐腐蚀性能,用火焰喷涂方法在镁合金表面制备Al-Mg2Si复合涂层.采用XRD、SEM和EDS分析涂层的物相组成、微观组织及元素分布;通过电化学试验测试样品在3.5％NaCl溶液中的腐蚀电位、腐蚀电流密度;通过3.5％NaCl溶液浸泡试验测试样品的腐蚀速率;并测试涂层的显微硬度.结果表明:涂层中的主要物相有Mg2Si、Al,组织比较致密,元素分布均匀.Tafel极化曲线测试表明,Al-Mg2Si涂层样品与AZ31B镁合金样品相比腐蚀电位从-1.489 V正移到-1.366 V,腐蚀电流密度从2.817×10-3 A/cm2降低到1.198×10-3 A/cm2.浸泡试验结果表明,喷涂Al-Mg2Si的镁合金的腐蚀速率明显低于没有喷涂的镁合金.显微硬度测试表明,涂层的显微硬度集中分布在259～308HV0.05之间,镁合金为50～60 HV0.05.因此在AZ31B镁合金表面火焰喷涂Al-Mg2Si涂层可以提高其耐腐蚀性能,表面硬度显著提高.

A1-Mg2Si coating was prepared on the AZ31B magnesium alloy by flame spraying to improve the corrosion resistance of the magnesium alloy.XRD,SEM and EDS were used to analyze the phase composition,microstructure and elements distribution.The potential corrosion and corrosion current density of the samples in 3.5 ％ NaCl solution were investigated by electrochemical experiment,and the corrosion rates were investigated by immersing experiment in the same solution.And the micro-hardness of the coating was tested.The results show that the coating is composed of Al and Mg2Si phases with a dense microstructure and uniform element distribution.Tafel polarization curves indicate that the potential corrosion of the coating is increased from-1.489 V to-1.366 V and the corrosion current density is decreased from 2.817× 10-3A/cm2 to 1.198 × 10-3 A/cm2,compared with that of the magnesium alloy.Corrosion rate of the coating is significantly decreased compared with that of magnesium alloy according to immersing experiment.Micro hardness of the coating is chiefly concentrated between 259-308 HV0.05 and that of the magnesium alloy is 50-60 HV0.05.Thus,the corrosion resistance and micro-hardness of the magnesium alloy are improved by flame spraying of Al-Mg2Si composite coating.