利用选择性腐蚀原理制备双相不锈钢(DSS)单相试样, 研究了在3.5% NaCl(质量分数)溶液和2 mol/L H2SO4+0.5 mol/L HCl溶液中铁素体(α)、奥氏体(γ)单相试样的电化学行为差异。结果表明: α相开路电位比γ相的低, 但钝化膜阻抗值比γ相的高;通过宏观电化学方法、微电极及XPS试验对双相不锈钢中α、γ单相间电偶作用进行了研究, 研究发现双相不锈钢两相间存在相互作用, α相促进γ相表面钝化膜稳定性的提升, 且这种作用效果与距离相关。

The exclusive ferritic phase (α-phase) and austenitic phase (γ-phase) specimens were prepared on duplex stainless steel (DSS) on the basis of selective dissolution method. The electrochemical behaviors of α-phase and γ-phase in 3.5% NaCl solution and 2 mol/L H2SO4+0.5 mol/L HCl solution were investigated. The results show that the open circuit potential of α-phase was lower than that of γ-phase, while the impedance of α-phase was higher. An electrochemical method, a micro-electrolytic cell arrangement and XPS testing were used for the electrochemical measurements to study the galvanic effect between two phases in DSS. It was found that α-phase contributed to the formation of passive film on γ-phase, so as to improve the corrosion resistance of the duplex stainless steel. The effect between two phases was related to the distance between them.