摘要
利用动电位回扫的方法研究了钨酸根离子(WO_4^(2-))对304不锈钢亚稳态孔蚀及稳定孔蚀的形核与生长阶段的影响。随着WO_4^(2-)浓度的增大,304不锈钢亚稳态孔蚀电位Em和稳定孔蚀电位Eb值均升高,即WO_4^(2-)浓度的增大,抑制了亚稳态孔蚀和稳定孔蚀的形核。WO_4^(2-)浓度增加导致亚稳态孔蚀的平均生长速度和电流峰值降低,从而降低了亚稳态孔蚀转化为稳定孔蚀的可能性,抑制了稳定孔蚀形核。WO_4^(2-)增加导致孔蚀回扫过程中的最大电流密度增大,再钝化电位Ep降低,即导致生长的稳定蚀孔更难于再钝化,其原因可能是钨酸盐膜在小孔孔口的沉淀会促进蚀孔生长的稳定性。
The effect of tungstate ions on metastable-and stable-pitting of 304 stainless steel in NaCl solution was assessed by cyclic scanning polarization test. As tungstate concentration increased, both the metastable-and the stable-pitting potentials, Emand Eb, increased, which shows that the nucleation of both metastable-and stable-pitting was inhibited. The average growth rate and peak current of metastable pitting decreased with the increasing WO4^2-concentration, which would decrease the probability of stable-pitting nucleation. However, during the back scanning process, the peak current of the pit increased and the repassivation potential decreased with increasing WO4^2-concentration, indicating that for the growing pit tungstate ions would retard the repassivation of the pit. A possible reason is the deposition of insoluble tungstate salts at the pit mouth thus may promote the stable growth of the pit.
作者
石慧英
左禹
SHI Huiying, ZUO Yu(School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, Chin)
出处
《腐蚀科学与防护技术》
CAS
CSCD
北大核心
2018年第2期167-171,共5页
Corrosion Science and Protection Technology
基金
国家自然科学基金(51210001)~~
关键词
WO4^2-
不锈钢
亚稳态孔蚀
稳定孔蚀
形核
生长
tungstate ions, stainless steel, metastable pitting, pitting, nucleation, growth
