N80钢模拟全浸区和干湿交替试样的腐蚀行为

Corrosion Behavior of N80 Steel under Immersion and Wet-dry Cyclic Condition

利用SEM和XRD对锈层的腐蚀形貌和腐蚀产物组成进行观察和分析,研究了N80裸钢和模拟全浸区腐蚀试样及模拟干湿交替腐蚀试样在两种海水介质中的极化行为。结果表明,干湿交替腐蚀阴极过程溶解氧还原的极限扩散控制特征基本消失,而受腐蚀产物还原为主的电荷传递控制。N80钢干湿交替腐蚀电流不仅包括钢自身的腐蚀电流,还包括腐蚀产物的氧化还原电流,导致了N80钢模拟干湿交替的腐蚀速率远大于全浸区腐蚀速率。

The polarization behavior of N80 steel was obtained from the corroded steel samples under wet-dry cyclic condition and compared with that from bare steel and immersion samples. The corrosion morphology and corrosion products of the steel samples were characterized using scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The cathodic reduction of samples under wet-dry cyclic condition was controlled mainly by the charge transfer step of reduction of corrosion products rather than the limiting diffusion control of dissolved oxygen. The matrix metal of the samples was corroded and the rust itself also took part in the reduction processes and hence increased the corrosion rate of the steel samples under wet-dry cyclic condition.