摘要
利用交流阻抗(EIS)和极化曲线 ,结合扫描电镜 (SEM)和能谱分析 ,对常温下低碳钢在含H2 S的模拟炼厂常减压塔顶冷凝水中的腐蚀电化学行为和不同浸泡时间下硫化物膜的生长过程进行了研究。结果表明 ,H2 S对腐蚀反应的阴极过程有很大的促进作用 ,搅拌条件下尤甚 ;随介质pH值升高 ,其腐蚀性减弱。腐蚀浸泡初期 (小于 8h) ,电极表面硫化物膜的生长遵循抛物线机制 ,随浸泡时间的延长 ,硫化物膜变得疏松、易于破裂和脱落 ,并出现二次生长、修复过程 ,最终达到膜生长和溶解的平衡。实验条件下电极表面所生成的硫化物膜 。
The electrochemical behavior of low carbon steel corroding in acidic simulation solutions containing H 2S was investigated by electrochemical impedance spectroscopy, potentiodynamic polarization curves and observations of SEM and ADEX. The results showed that the cathodic depolarization was enhanced greatly by H + ionized from H 2S under stirring or static condition. Corrosion rate decreased with increasing pH within the investigated pH range. The transfer resistance (R t) initially increased with immersion time up to about 8h, but then decreased sharply. At the initial stage of corrosion, the growth of sulfide film on the electrode suface abided by parabolic law, but after longer immersion, the sulfide film became loose, easily cracked and sloughed off, furthermore, the second growth of film arose. Finally, the growth of film was balanced by its dissolution in solution. Sulfide film formed under test condition was not protective enough for carbon steel.
出处
《中国腐蚀与防护学报》
CAS
CSCD
2000年第1期1-7,共7页
Journal of Chinese Society For Corrosion and Protection
