Corrosion of Glassy (Ni8Nb5)99.5Sb0.5 Alloy and Stability of Passive Film

摘要:

通过浸泡法和电化学腐蚀法研究了(Ni8Nb5)99.5Sb0.5非晶在1，6 mol/L HCl, 1 mol/L H2SO4 和 3% NaCl (质量分数)溶液中的腐蚀行为，对相应的组分金属Ni, Nb和Sb的腐蚀行为进行了比较。钝化膜的稳定性使用恒电位法和XPS深度剖析进行了研究，电化学极化测试后用扫描电镜观察了合金的表面形貌。结果表明，Ni-Nb-Sb合金在1 mol/L HCl, 1 mol/L H2SO4和3% NaCl (质量分数)溶液中具有良好的抗腐蚀性，在6 mol/L HCl溶液中，非晶合金的抗腐蚀性较差。在含有氯的介质中，电化学腐蚀后非晶合金表面被晶化，且有过钝化溶解。对钝化膜的稳定性研究表明，在低电压下，钝化膜的生长是由扩散控制的，而在高电压下，则主要呈活化腐蚀

Abstract:

The corrosion of glassy (Ni8Nb5)99.5Sb0.5 alloy was investigated in 1, 6 mol/L HCl, 1 mol/L H2SO4 and 3% NaCl solutions, respectively, by immersion tests and electrochemical measurements and compared with that of pure Ni, Nb and Sb. The stability of passive film was studied using potentiostatic current transients and XPS depth profiling. The surface morphology of the glassy alloy after electrochemical potentiodynamic polarization test was observed using SEM. The result indicates that the Ni-Nb-Sb alloy shows good corrosion resistance in 1 mol/L HCl, 1 mol/L H2SO4 and 3 wt% NaCl solutions. The corrosion resistance, however, is poor in 6 mol/L HCl solution. The amorphous alloy is crystallized after electrochemical corrosion in chloride media. Transpassive dissolution is observed during potentiodynamic polarization test in chloride media, which appears to be associated with oxygen evolution. At low potentials, the growth of passive film is diffusion-controlled. At high potentials, however, the active corrosion is the predominant.