硫化氢质量浓度和温度对碳钢在NACE溶液中腐蚀行为的影响

采用动电位极化曲线和电化学阻抗谱等电化学实验方法以及扫描电镜和能谱等表面分析技术对20#碳钢在不同H2S质量浓度(0,95.61,103.22,224.16 mg.L-1)、不同温度(25,35,45℃)下的NACE溶液(含CO2)中腐蚀行为进行了研究,同时对该环境下腐蚀产物的形成机制进行了探讨.发现在含有CO2的NACE溶液中,加入少量H2S,能加剧碳钢腐蚀,加速阳极铁的溶解和阴极氢气的析出.随着H2S质量浓度的增加,腐蚀电流密度增大,碳钢腐蚀加剧.温度升高,腐蚀极化电阻变小,腐蚀也会加剧.腐蚀试样外层絮状腐蚀产物主要是铁碳化物,接近基体表面的腐蚀产物主要是铁硫化物.

Effect of H2S concentration and temperature on the corrosion behavior of carbon steel in NACE solution

The electrochemical corrosion behavior of 20# carbon steel in NACE solutions containing different mass concentrations of H2S(0,95.61,103.22,and 224.16 mg·L-1) at different temperatures(25,35,and 45 ℃) was investigated by potentiodynamic polarization tests,electrochemical impedance spectroscopy(EIS),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS).The formation mechanism of corrosion products was also discussed.It is found that the corrosion rate of the carbon steel increases significantly with the addition of a small amount of H2S in the NACE solution by promoting both the anodic iron dissolution and the cathodic hydrogen evolution.The corrosion current density of the carbon steel enhances with the increment of H2S concentration.As the temperature of the electrolyte solution increasing,the corrosion rate also increases.The outer loose corrosion products are mainly iron carbonate;but corrosion products formed on the steel surface are mainly composed of iron sulfides.