采用D−S双电解池研究7075-T6铝合金的表观氢渗透系数，对表面镀镍厚度、充氢电流和循环次数对表观氢渗透系数的影响进行研究，进一步研究表面镀镍充氢试样的应力腐蚀敏感性。结果表明：表面镀镍厚度为220 nm 时，钝化电流最为稳定，镀镍层厚度对氢渗透电流的影响主要体现在对氢原子的氧化能力和对铝合金基体的保护能力上。表观氢渗透系数随充氢电流增大有增大的趋势，主要与表面氢原子深度增大、深度梯度增大以及加速氢向铝合金的渗透相关。但是增大幅度表观氢渗透系数有减小的趋势，主要原因是由于氢的表面覆盖度增大后，大部分的氢原子开始结合为氢气而脱离铝合金表面。随着循环次数的增加，表观氢渗透系数也随之增大，主要原因是随着循环次数增加，铝合金内部的不可扩散氢深度趋于稳定，可扩散氢的渗透速度增大。SSRT 实验分析和SEM电镜照片结果表明：随充氢时间的增长，SSRT敏感性增大，氢能够渗入铝合金内部，并使其脆性增大，且其脆性随着充氢时间延长而有所增大。%The apparent hydrogen diffusivity was studied by D−S double cell. The effect of thickness of plated Ni, charging current density and charging-uncharging cycles on apparent hydrogen diffusivity was studied. And the stress corrosion cracking (SCC) sensitivity of constant charging specimens was studied. The results show that the passivation current is steady while the thickness of plated Ni is 220 nm. The plated Ni can provide protection from pitting corrosion and catalysis effect on hydrogen. The apparent hydrogen diffusivity increases with the increase of charging current density. The surface hydrogen concentration increases with the increase of charging current density, and the concentration gradient also increases, the hydrogen permeation rate increases, while the increase trend becomes slow due to the surface coverage. The apparent hydrogen diffusivity increases with the increase of charging-uncharging cycles at the beginning, and then reaches a steady value due to the overflow of non-diffuse hydrogen and the increase of hydrogen permeation rate. And the SCC sensitivity of constant charging specimens increases with the increase of charging time.
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