阳极电位对锆在异丙醇中溶解行为的影响  

Effect of anodic potential on dissolution of zirconium in isopropyl alcohol solution

作　　者：杨喜云 黄海强 杨声海 YANG Xiyun HUANG Haiqiang YANG Shenghai(School of Metallurgy and Environment, Central South University, Changsha 4 i 0083, Chin)

机构地区：[1]中南大学冶金与环境学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2017年第9期2257-2263,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51374254)~~

摘　　要：采用循环伏安法(CV)、计时电流法、交流阻抗法(EIS)、扫描电镜(SEM)和X线光电子能谱(XPS)研究不同电位下锆在异丙醇溶液中阳极溶解行为。研究结果表明:当阳极电位为0~1.10 V时,锆表面存在氧化膜导致钝化,不发生活性溶解;交流阻抗复数平面图出现大的容抗弧;自腐蚀电位随时间延长而增大;当阳极电位大于1.10 V,Br^-击穿钝化膜使锆发生活性溶解,锆溶解属于点蚀,交流阻抗复数平面图在高频区出现容抗弧,在中频区出现感抗弧,在低频区出现Warburg阻抗;稳态点蚀电位处于1.10~1.20 V之间,点蚀的成核方式为瞬间三维成核,生长过程为扩散控制;提高阳极电位,点蚀加剧,腐蚀面积加大,腐蚀孔加深,容抗弧直径减小;锆表面钝化膜的主要成分为ZrO_2,在异丙醇溶液中溶解生成Zr(OC_3H_7)_4。Anodic dissolution of zirconium in isopropyl alcohol solution containing Bun4 NBr at different potentials was investigated using cyclic voltammetry, potentiostatic current-time transient, A.C. impedance techniques, SEM and X-ray photoelectron spectroscopy（XPS）. The results show that zirconium does not exhibit active dissolution due to the presence of passive film on surface, and the large capacitance loop appears in the anodic potential range of 0 to 1.10 V and open circuit potential increases with time. When the anodic potential is greater than 1.10 V, zirconium suffers from pitting corrosion due to the aggressive attack of passive film by bromide anions. Correspondingly, the Nyquist plot shows a large capacitance loop at high frequencies, an inductive loop at the middle frequencies and a warburg impedance at the low frequencies. The stable pitting potential is between 1.10 V and 1.20 V. The pit growth is an instantaneous threedimensional nucleation followed by growth controlled by diffusion. With the increase of anodic potential, the pitting corrosion accelerates, which is indicated by deeper pits, larger corrosion area and a smaller capacitance loop at the high frequencies. Zirconium surface has a layer of passive film mainly composed of ZrO2 and dissolves to produce Zr（OC3H7）4.

关 键 词：锆 点蚀 异丙醇 阳极电位 

分 类 号：TQ150[化学工程—电化学工业]