利用干湿循环加速腐蚀实验方法研究了Mn-Cu低合金钢在模拟海岸大气条件下的锈蚀演化规律.结果表明,在腐蚀初期锈蚀速度随干湿循环次数的增加而增大,随后转为随干湿循环次数的增加而降低.带锈层的Mn-Cu低合金钢的电化学极化行为表明,干湿循环下的腐蚀产物促进阴极过程,抑制阳极过程.在干湿循环加速腐蚀进程中Mn-Cu低合金钢表面铁锈的化学组成、结构变化表现为在锈蚀初期α-FeOOH含量较低,锈层疏松,锈蚀速度呈随干湿循环次数增加而上升趋势;后期随α-FeOOH含量的增加和锈层变得更加致密,腐蚀速度转变为随干湿循环次数增加而下降.锈蚀演化过程中,腐蚀速度和极化行为随干湿交替次数的演化与相应的锈层组成、结构形貌的变化有对应关系.
In this paper,the rusting evolution of low Mn-Cu alloyed steel in a simulated coastal environment was studied by cyclic wet/dry accelerated corrosion test(CCT).It showed that the corrosion rate increased with increasing the CCT cycles in the initial stage of CCT,whereafter it decreased with increasing the CCT cycles in the subsequent stage.The polarization behavior of the rusted steel indicated that the corrosion product promoted the cathodic process while restrained the anodic process.During the initial rusting stage,the rust showed a loose structure and low content of α-FeOOH.Whereafter the rust became dense and the content of α-FeOOH increased.