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利用电化学阻抗和动电位极化技术,研究了Q235钢在不同浓度的S2-、Cl-及NH4+作用下的电化学行为,并对离子协同作用下Q235钢的腐蚀敏感性影响进行了比较分析。结果表明:Q235钢在S2-或NH4+作用下阳极极化过程呈钝态,Cl-作用下表现为活化极化。Q235钢腐蚀电流密度随Cl-或NH4+浓度的增加而增大,但随S2-浓度的增加而减小。Q235钢在碱性硫化物环境中能生成保护性钝化膜。溶液中的Cl-和S2-在钝化膜的缺陷部位吸附,破坏了钝化膜的进一步生成,使膜下金属处于活化状态,加速了腐蚀过程。
The electrochemical behavior of Q235 steel under different concentrations of S2-, Cl- and NH4 + was investigated by means of electrochemical impedance and potentiodynamic polarization. The corrosion susceptibility of Q235 steel under ionic synergism was compared and analyzed. . The results show that the Q235 steel is passivated by S2- or NH4 + and the polarization is activated by Cl-. The corrosion current density of Q235 steel increased with the increase of Cl- or NH4 + concentration, but decreased with the increase of S2- concentration. Q235 steel in the alkaline sulfide environment can generate protective passivation film. The Cl- and S2- in the solution adsorb on the defect sites of the passivation film, which destroy the further formation of the passivation film and activate the under-film metal, accelerating the corrosion process.