S^(2-)对高强Cu-7Ni-3Al合金在NaCl溶液中耐蚀性能的影响

Effect of S^(2-) on Corrosion Resistance of Cu-7Ni-3Al Alloy in NaCl Solutions

实验以铜镍系耐蚀铜合金为基础,利用真空熔炼法制备得到Cu-7Ni-3Al合金,通过静态浸泡法对Cu-7Ni-3Al在不同S^(2-)浓度的3.5%(w) NaCl溶液中的腐蚀速率及腐蚀形态进行了研究。结果表明,通过真空熔炼法能制备出综合力学性能良好的Cu-7Ni-3Al合金。S^(2-)的存在促进了Cu-7Ni-3Al合金的腐蚀,Cu-7Ni-3Al合金的腐蚀速率随S^(2-)浓度的增大而增大,原因在于Cu-7Ni-3Al合金在S^(2-)环境中会形成Cu_(2)S,Cu_(2)S会使表面钝化膜变脆,并且阻止氧化膜的生成从而使腐蚀加速,因此Cu-7Ni-3Al合金在3.5%NaCl溶液中随S^(2-)含量的增加,耐蚀性下降。

Cu-7Ni-3Al copper alloy is prepared by vacuum smelting based on the copper-nickel corrosion-resistant copper alloys.The corrosion rate and corrosion pattern of Cu-7Ni-3Al alloy in 3.5%(w) NaCl solutions with different concentrations of S^(2-) are analyzed by the static total impregnation corrosion experiment.The results show that Cu-7Ni-3Al alloy with good comprehensive performance is prepared by vacuum smelting.The existence of S^(2-) promotes the corrosion of Cu-7Ni-3Al alloy.The corrosion rate of Cu-7Ni-3Al alloy increases with the increase of S^(2-)concentration,because in the environment of S^(2-),Cu-7Ni-3Al alloys will form Cu_2S,and Cu_(2S) will make the passivated film brittle and prevent the formation of oxide film,thus accelerating corrosion.Therefore,the corrosion resistance of Cu-7Ni-3Al alloy decreases with the increase of S^(2-)content in 3.5% NaCl solution.