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采用开尔文探针技术(SKP)测量AZ91D镁合金与H62铜合金偶接试样在盐雾加速实验中的电偶腐蚀规律.研究表明:AZ91D镁合金的电偶腐蚀效应受到阳极与阴极的电位差的影响,AZ91D镁合金与H62铜合金偶接试样之间的伏打电位差约为-1.22V,AZ91D镁合金存在显著的电偶腐蚀效应.由于存在较大的伏打电位差,在盐雾实验初始阶段,电偶腐蚀主要发生在偶接界面AZ91D镁合金一侧附近区域,而H62黄铜没有发生明显腐蚀.由于AZ91D镁合金在盐雾中生成的腐蚀产物对基体具有一定的保护作用,AZ91D镁合金表面腐蚀产物与基体间存在显著的伏打电位差,导致AZ91D镁合金基体形成新的腐蚀产物.因此,随着盐雾实验时间延长,AZ91D镁合金电偶腐蚀效应降低,H62铜合金腐蚀加快.
Galvanic corrosion of AZ91D magnesium alloy and H62 copper alloy in the salt spray accelerated test was measured by Kelvin probe technique.The results show that the galvanic corrosion effect of AZ91D magnesium alloy is affected by the potential difference between anode and cathode , The potential difference between AZ91D magnesium alloy and H62 copper alloy coupling sample is about -1.22V, and there is a significant galvanic corrosion effect on AZ91D magnesium alloy.Because of the large potential difference between volts, In the initial stage of fog test, the galvanic corrosion occurred mainly in the vicinity of one side of the AZ91D magnesium alloy coupled with the interface, while the H62 brass did not show any significant corrosion.Because the corrosion products generated by the AZ91D magnesium alloy in the salt spray had a certain protective effect on the matrix , AZ91D magnesium alloy surface corrosion products and the substrate there is a significant volt potential difference, resulting in AZ91D magnesium alloy matrix formed a new corrosion product.Therefore, with the salt spray test time extension, AZ91D magnesium alloy galvanic corrosion effect decreased, H62 copper Corrosion of the alloy accelerated.