Passivity of 2205 duplex stainless steel (DSS) with different surface pre-conditionings was investigated in thiosulfate-containing solutions using electrochemical tests, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and density functional theory (DFT). While thiosulfate had no effect on air-passivated DSS in the primary passive range, it influenced fresh DSS when the air-passivated film was cathodically or mechanically removed. Surface analysis by ToF-SIMS revealed that iron sulfide was incorporated in the passive film formed on an air-passivated surface, while iron, chromium, and nickel sulfides were incorporated in the passive film formed on fresh surfaces. DFT modelling supported experimental observations.

使用电化学测试、飞行时间二次离子质谱 (ToF-SIMS) 和密度泛函理论 (DFT)，研究了具有不同表面预处理的 2205 双相不锈钢 (DSS) 在含硫代硫酸盐溶液中的钝化性。虽然硫代硫酸盐对初级被动范围内的空气钝化 DSS 没有影响，但当空气钝化膜被阴极或机械去除时，它会影响新鲜的 DSS。通过 ToF-SIMS 进行的表面分析表明，空气钝化表面上形成的钝化膜中含有硫化铁，而新表面上形成的钝化膜中含有硫化铁、铬和硫化镍。DFT 建模支持实验观察。