Effect of HAc on the Metastable Pitting Corrosion of 304 SS in NaCl Solution

Materials

卷:15

Yu Zuo¹  Yuming Tang¹  Zilong Chen¹  Han Wei¹  Wenqiang Huang¹  Xuhui Zhao¹  Jingyi Cao²  Hanlu Zhang² 

[1]Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, China

[2]|No. 92228 of the People’s Liberation Army, Beijing 100072, China

关键词: 304 stainless steel;    0.6 mol/L NaCl;    metastable pitting corrosion;    acetic acid;    pH;   

DOI  :  10.3390/ma15103618

来源: DOAJ

【 摘 要 】

Stainless steels (SSs) easily suffer localized corrosion damage, such as pitting corrosion, in mixed solutions of acetic acid and sodium chloride. Currently, few works have been focused on the early stages of the pitting corrosion (metastable pitting corrosion) process of SSs in a chloride-HAc mixture solution. In this work, the effects of acetic acid (HAc) and its concentration on metastable pitting corrosion and the uniform corrosion of 304 SS in 0.6 mol/L NaCl solution were investigated by a slow-scanning potentiodynamic polarization test, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results show that the uniform corrosion rate of 304 SS increases after HAc addition but, with an increase in HAc concentration, the corrosion rate decreases. In the presence of HAc, the metastable pitting potential (E_m) and stable pitting potential (E_b) move negatively, but the number of metastable pits notably decreases. HAc has a promoting action on the growth rate of the metastable pits and facilitates the transition from metastable pits to stable pits. The influence of HAc is related to a decrease in solution pH and the chemical adsorption of HAc.

【 授权许可】

Unknown