黄铜选择性溶解固相扩散机理的研究

A STUDY OF THE SOLID-STATE DIFFUSION MECHANISM ON SELECTIVE DISSOLUTION OF ZINC IN BRASSES

采用恒电位暂态和旋转盘环电极等方法研究了α、α＋β以及β黄铜在硫酸钠、硫酸以及氯化钠的稀溶液中的阳极溶解过程．结果表明，在黄铜阳极溶解的初始阶段测得的ｉ－ｔ曲线遵循抛物线定律，求得ｉ－ｔ为一通过坐标原点的直线，证明了黄铜中锌的选择性溶解受固相扩散控制，计算出在上述溶液中黄铜中锌的扩散系数值在１０－１５～１０－１３ｃｍ２·ｓ－１数量级，介质成分和微量合金元素砷对扩散系数值有明显的影响．

The anodic dissolution of Cu32Zn,Cu38Zn and Cu51Zn in dilute solutions ofsodium sulphate,sulphate acid and sodium chloride was investigated by potentiostatic transient and RRDE techniques. The results show that the current-time relation obtained followsthe parabolic rate law on the initial period of anodic dissolution of brasses. Thus,it is provedthat the selective dissolution of zinc in brass is controlled by a solid-state diffusion process. Interms of the slopes of i-t-1/2 straight lines,the diffusion coefficients of zinc in brasses werecalculated to be of the order of 10-15 ～ 10-13 cm2. S-1. Furthermore, the components ofmedium and the arsenic in brasses significantly affect the values of the diffusion coefficient.