两次动电位极化中316L不锈钢孔蚀参数的变化

以0.01mol/L NaCl溶液中的316L不锈钢为研究对象，采用慢速动电位扫描法研究了第一次极化只发生亚稳态孔蚀、同时发生亚稳态和稳态孔蚀两种条件对再次极化时小孔形核与生长的影响。结果表明，两种极化条件对不锈钢再次极化时的孔蚀行为的影响并不明显；两种极化条件下的第一次极化均导致材料表面活性点显著减少，从而再次极化后亚稳孔形核数目明显减少，同时亚稳态孔蚀电位和稳定孔蚀电位都有所升高；两种极化条件下的第二次极化过程中产生的亚稳态小孔的峰值电流和平均生长速度与初次极化相比有所增大，其原因主要是第二次极化的电位范围更高。

Changes in pitting corrosion parameters of 316L stainless steel for two potentiodynamic polarization modes

The influences of repeated polarization on the pitting parameters of 316L stainless steel in 0.01 mol/L NaCl solution have been studied using slow rate potentiodynamic polarization. The tests were carried out under two different conditions: in condition A, the first polarization was stopped before stable pitting occurred; in condition B, the first polarization was stopped after stable pitting occurred. Then the second polarization was run to determine the influence of the metastable pits and stable pits formed during the first polarization on the subsequent pitting process. The results show that the two initial polarization conditions have little impact on pitting corrosion behavior during the second polarization. Under both conditions, the first polarization reduced the active points on the material surface and led to decreased nucleation rate of metastable pitting, and both the metastable pitting potential E_m and stable pitting potential E_b increased. Compare with the initial polarization, the peak current and the average growth rate of metastable pits in the second polarization increased, which may be attributed to the higher polarization potential range during the second polarization.