摘要
利用动电位法测定316L奥氏体不锈钢和R1双相不锈钢在C_5H_6O_4-Cl^--NO_3^-水溶液体系中的阳极极化曲线和点蚀电位,探讨了衣康酸(C_5H_6O_4)介质中Cl^-和NO_3^-对点蚀的影响。结果表明:(1)Cl^-浓度[Cl^-]的提高导致不锈钢点蚀电位E_b降低,其关系为E_b=a-blg[Cl^-]。同样条件下,R1不锈钢的点蚀电位比316L不锈钢高300～400mV;(2)在含Cl^-的衣康酸介质中,加入NaNO_3可使不锈钢点蚀电位正移至过钝化电位。在一定温度下,完全抑制点蚀所需的NaNO_3临界浓度因Cl^-含量和钢种而异。
By measuring the anodic polarization curves and pitting potentials of two stainless steels (316L and duplex type termed Rl) in itaconic acid aqueous solutions containing Cl- and NOr anions , the effect of Cl- and NO3 on pitting corrosion of the steels was investigated. The results showed that: (a) The pitting potential of the steels decreased linearly with the increase of logarithmic value of the Cl- concentration in itaconic acid solutions. The Rl duplex steel showed much higher pitting potential than 316L steel under the same test conditions. (b) By addition of NaNO3 to Cl- containing itaconic acid solutions, the pitting potential of the two steels could be increased up to their transpassive potentials so as to prevent pitting corrosion. The critical concentration of NaNO3 required for complete pitting inhibition varied with the steel's type and Cl- content when the temperature remained constant.
出处
《腐蚀与防护》
CAS
1999年第7期307-309,313,共4页
Corrosion & Protection
基金
云南省自然科学基金
关键词
不锈钢
衣康酸
点蚀电位
缓蚀剂
氯
硝酸
Stainless steel Itaconic acid Pitting potential Pitting inhibitor
