纳米Cu-20Co-20Ni合金在中性Na2SO4溶液中腐蚀行为研究

Study on the Corrosion Electrochemical Behavior of Nanocrystalline Cu-20Co-20Ni Alloy in Neutral NaSO Solution

纳米材料的物理性质和化学性质研究在国内外引起了广泛的关注,目前有关纳米材料的腐蚀性能研究主要集中在纳米薄膜和纳米涂层上,而对块合金耐蚀性的研究较少。实验用机械合金化(MA)制备了纳米晶的Cu-20Co-20Ni合金粉末,用粉末冶金法(PM)制备了常规尺寸的Cu-20Co-20Ni合金粉末。采用真空热压工艺制备Cu-20Co-20Ni合金块体。通过测量Cu-20Co-20Ni合金在Na2SO4溶液中的开路电位、动电位极化曲线和交流阻抗,对其腐蚀性能进行了研究。结果表明:随着晶粒的细化,自腐蚀电位变负,腐蚀电流密度增大,电荷传递电阻变小,耐腐蚀性减弱,即纳米晶Cu-20Co-20Ni合金的耐腐蚀性能相比常规尺寸Cu-20Co-20Ni合金差。

The research on physical and chemical properties of nanomaterials has attracted wide attention.At present,the research on corrosion properties of nanomaterials mainly focuses on films and coatings,while the research on the corrosion resistances of bulk alloys is relatively rare.In this paper,both the nanocrystalline and conventional size Cu-20Co-20Ni alloy powders were prepared by mechanical alloying (MA) and powder metallurgy (PM).The corresponding bulk Cu-20Co-20Ni alloys were prepared by vacuum hot pressing processes.The corrosion properties of two Cu-20Co-20Ni alloys in Na2SO4 solution were studied by measuring the open-circuit potential and potentiodynamic polarization curves,and electrochemical impedance microscopies.The results showed that,with the refinement of grain size,the self-etching potential became negative,the corrosion current density increased,the charge transfer resistance decreased,and therefore the corrosion resistance weakened.In other words,the corrosion resistance of the nanocrystalline Cu-20Co-20Ni alloy was worse than that of conventional size Cu-20Co-20Ni alloy.