摘要
应用电位阶跃和交流阻抗法分别研究铅和Pb-5wt%Sb合金在4.5mol·dm^(-3)H_2SO_4(30℃)中于1.3V(vs.Hg/Hg_2SO_4,下同)生长20min后的阳极膜在0.9V还原5min后再在1.4V将膜中硫酸铅氧化的过程.实验结果表明在0.9V还原二氧化铅而得到的硫酸铅能在1.4V于1min内氧化为二氧化铝.这是由于此种硫酸铅处于硫酸铅颗粒表层的缘故.至于颗粒内部由铅直接生成的硫酸铅的氧化为二氧化铅就要缓慢得多.合金中的锑能使二氧化铅晶核形成和生长速率显著降低.
The oxidation processes of lead sulphate in the anodic films on lead and Pb-5wt% Sb alloy, which were formed by the reduction at 0.9V (vs. Hg/ Hg2SO4, the same reference electrode below) for 5 min of the anodic films grown in a 4.5mol · dm-3 H2SO4 solution (30℃) at 1.3V for 20 min, have been studied using potential step and a.c. impedance methods respectively. The experimental results show that the lead sulphate, which is formed by reducing lead dioxide, can be reoxidized to lead dioxide within 1 min at 1.4V. This is due to the fact that this kind of lead sulphate is at the surface layers of the lead sulphate grains in the anodic film. The oxidation process of lead sulphate in the inner part of the grain, which is formed directly by anodizing lead, is much slower. The antimony in the lead alloy inhibits significantly the nucleation and growth of lead dioxide crystals.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1995年第4期313-317,共5页
Acta Chimica Sinica
基金
国家自然科学基金资助的课题.
