金属Ni阳极溶解与钝化的机理研究

来源期刊：中南大学学报(自然科学版)1987年第3期

论文作者：曾振欧 周倜

文章页码：338 - 343

关键词：镍； 金属电极； 可溶性阳极电解； 自钝化； 电化学反应； 电化学动力学；钝化

Key words：nickel； metal electrode； soluble-anode electrolysis； self-passivation； eletrochemical reaction； electrochemical kinetics；passication

摘    要：本文采用动电位扫描方法研究了硫酸盐水溶液中的金属Ni阳极过程。金属Ni阳极溶解与钝化表现为电荷传递分步进行、并以失去第一个电子的电化学反应为控制步骤的不可逆电极过程。金属Ni阳极正常溶解速度与电解质溶液组成浓度无关,而钝化是由于阳极极化电位较高时失去第二个电子的电化学反应直接生成固态NiO成相膜复盖电极表面所引起。综合实验研究事实和理论分析结果,本文提出了金属Ni阳极溶解与钝化反应的可能机理。

Abstract: The anodic dissolution and passivation of nickel in aqueous sulphate solution have been studied by the potential sweep method. Both anodic dissolution and passivation of nickel are irreversible electrode processes in which the charge transfers occur in two consecutive steps and the first electrochemical step is a rate-determining step. The anodic dissolutiow of nickel is independent of concentrations of solution composition and its passivation is caused by the second electrochemical reaction in which the solid NiO is formed. The possible mechanisms of electrode reaction of the anodic process which have been shown by the study are as follows:Anodic dissolution, Ni+H₂O—→NiOH_ads+H⁺ +e NiOH_ads—→^NiOH⁺ +e NiOH⁺ +H⁺—→Ni²⁺ +H₂O Anodic passivation, Ni+H₂O.—→NiOH_ads+H⁺ +e NiOH_ads—→NiO₅+ H⁺ +e NiO₂+2H⁺—→Ni²⁺+H₂0