Al含量对Cu-Ni系粉末冶金合金耐蚀性能的影响

Effect of Al Content on the Corrosion Resistance of Cu-Ni Powder Metallurgy Alloy

为了提高Cu-10Ni合金的耐腐蚀性能,利用粉末冶金法在传统Cu-10Ni合金的基础上添加不同比例Al元素,制备得到系列Cu-Ni-Al合金。通过扫描电子显微镜、静态全浸腐蚀试验和电化学测试,研究了Al添加量和Cl^(-)浓度对Cu-Ni-Al合金耐蚀性能的影响。结果表明,放电等离子烧结(SPS)可以制备出致密性、硬度、电导率等综合性能优良的Cu-Ni-Al合金。Cu-Ni-Al合金在NaCl腐蚀介质中长时间浸泡,合金表面逐渐形成含有Cu_(2)O的腐蚀保护膜,同时Cu_(2)O保护膜外层会与腐蚀介质中的Cl^(-)发生进一步反应,形成一层Cu_(2)(OH)_(3)Cl产物膜,进而于合金表面形成Cu_(2)O和Cu_(2)(OH)_(3)Cl双层膜结构。Al含量相同时,随着腐蚀液中Cl^(-)浓度的提高,合金腐蚀逐渐加剧,表明在一定范围内Cl^(-)浓度的提升会促进腐蚀。

For improving the corrosion resistance of Cu-10Ni alloy,a series of Cu-Ni-Al alloys were prepared by powder metallurgy method with adding Al element in different proportions in the basis of traditional Cu-10Ni alloy.The effects of different contents of Al element and Clconcentrations on the corrosion resistance of Cu-Ni-Al alloy were studied by scanning electron microscopy(SEM),static total immersion corro-sion experiment and electrochemical test.Results showed that spark plasma sintering(SPS)could prepare Cu-Ni-Al alloy with excellent com-prehensive properties,such as density,hardness,conductivity,etc.When Cu-Ni-Al alloy was soaked in NaCl corrosion medium for a long time,a corrosion protection film containing Cu_(2)O was gradually formed on the surface of the alloy.Meanwhile,the outer layer of Cu_(2)O protec-tive film would further react with Cl^(-)in the corrosion medium to form Cu_(2)(OH)_(3)Cl product film,and furthermore,the Cu_(2)O and Cu_(2)(OH)_(3)Cl bilayer films were formed on the alloy surface.When content of Al element was the same,the increase of Cl^(-)concentration in the corrosive liq-uid caused that the corrosion of the alloy became more serious,which indicated that within a certain test range,the increase of the concentra-tion of the Cl^(-)would promote the corrosion.