物理化学学报 >> 2003, Vol. 19 >> Issue (04): 372-375.doi: 10.3866/PKU.WHXB20030420

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纯铝在强碱溶液中阳极溶解的电化学阻抗谱解析

邵海波;张鉴清;王建明;曹楚南   

  1. 浙江大学化学系，杭州　310027；腐蚀与防护国家重点实验室，沈阳　110015
  • 收稿日期:2002-07-09 修回日期:2002-10-22 发布日期:2003-04-15
  • 通讯作者: 王建明 E-mail:cncao@sun.zju.edu.cn

EIS Analysis on the Anodic Dissolution Process of Pure Aluminum in an Alkaline Solution

Shao Hai-Bo;Zhang Jian-Qing;Wang Jian-Ming;Cao Chu-Nan   

  1. Department of Chemistry, Zhejiang University, Hangzhou　310027; State Key Laboratory of Corrosion and Protection, Shenyang　110015
  • Received:2002-07-09 Revised:2002-10-22 Published:2003-04-15
  • Contact: Wang Jian-Ming E-mail:cncao@sun.zju.edu.cn

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摘要： 依据曹楚南提出的法拉第导纳表达式，拟合了纯铝在强碱溶液中的阳极溶解过程的电化学阻抗谱，并据此提出了这一反应进行的机理.结果表明,阻抗谱中的低频容抗弧是由表面裸露的Al转变为中间产物Al(OH)ads的反应引起的，而中频感抗弧则由Al(OH)ads转变为Al(OH)3,ads的反应引起.法拉第导纳的时间常数τ1和τ2的物理意义是物种Al(ss)和Al(OH)ads在单位表面活性位上的转化时间. τ1 >0和τ2 >0是符合稳定性条件的，也能够满足Kramers-Kronig转化的必要条件. g1和g2是与物种Al(ss)和Al(OH)ads在电极表面的覆盖密度随电位E变化有关的参数，由g1< 0可知随电位升高，纯铝表面的活性位面积减小.

关键词: 纯铝, 强碱溶液, 阳极溶解, 电化学阻抗谱(EIS), 解析

Abstract: The EIS of the anodic dissolution process of pure aluminum in an alkaline solution was fitted using an expression of Faradic admittance previously proposed by Cao[11-12], based on which the mechanism of the process was proposed. The results show that the capacitive loop in low frequency region of EIS is caused by the reaction of Al (ss), and the inductive loop in middle frequency region is caused by the reaction of Al(OH)ads. The time constants of Faradic admittance τ1 and τ2 mean the converting time of unit species Al(ss) and Al(OH)ads on unit bare surface site. Generally, τ1 and τ2 both decrease with the increase of the potential E.τ1 >0, τ2 >0, satisfy the conditions required by stability, and by Kramers-Kronig transforms as well. g1 and g2 relate to the variation of covering density of reactants Al(ss) and Al(OH)ads. g1< 0 indicates that the aluminum surface tends to be passive when the potential increases.

Key words: Pure aluminum, Alkaline solution, Anodic dissolution, Electrical impedance spectrum (EIS), Analysis