钨酸根离子对304不锈钢亚稳态与稳态孔蚀形核与生长的影响  

Effect of Tungstate Ions on Nucleation and Growth of Metastable-and Stable-pitting of 304 Stainless Steel in NaCl Solution

作　　者：石慧英[1] 左禹[1] SHI Huiying, ZUO Yu(School of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, Chin)

机构地区：[1]北京化工大学材料科学与工程学院,北京100029

出　　处：《腐蚀科学与防护技术》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)~~

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.

关 键 词：WO4^2- 不锈钢 亚稳态孔蚀 稳定孔蚀 形核 生长 

分 类 号：TG174[金属学及工艺—金属表面处理]