钢在氰化镀镉过程中的渗氢行为

Behaviors of Hydrogen Permeating into Steel During Cadmium Plating from Cyanide Bath

对钢和预镀镉的钢在0.2N NaoH中,电解充氢时以及在氰化镀镉过程中的渗氢瞬变电流分别进行了测量。对于电解充氢,测得的稳态渗氢电流P_∞同充氢电流的平方根呈线性关系,原子氢在钢中的扩散系数为6.67×10^(-6)cm^2·S^(-1);而在氰化镀镉过程中,钢基底的渗氢仅出现在电沉积的初期,即开始电沉积的前4min。本文提出了随水分子放电之后发生的析氢与渗氢两个平行竞争的过程机理,很好地解释了实验结果。

Measurements of the transient current of hydrogen permeation through steel and/or cadmium-plated steel during cathodic charging in 0.2N NaOH solution and cadmium plating from cyanide bath has been carried out. When the steel is undergone cathodic polarization in 0. 2N NaOH, the steady permeation current measured is linearly related to the square root of charging current. The diffusion coefficient of hydrogen atom permeated into steel is 6.67×10^(-6)cm^2·s^(-1) And, the permeation of hydrogen into steel during cadmium plating occurs only in the initial period, that is at the first 4min. after starting. The mechanism of the competitive processes of the penetration and evolution of hydrogen which occur simultaneously during water discharging has been proposed and gives a satisfactory explanation to the experiment results.