Pd8Y0.23Ru合金膜氢渗透率稳定性的研究

Study on the Stability of Hydrogen Permeability of Pd8Y0.23Ru Alloy Membrane

针对Pd8Y0.23Ru合金膜在透氢起始阶段氢渗透率不稳定的问题,分别采用XPS、SEM以及XRD对合金膜的表面成分、形貌以及相结构进行了研究。结果表明,氢渗透率升高是由两方面原因造成的:一是氢渗透过程中除去了占据合金膜表面活性解离位点的含C杂质,加快了氢气的解离,渗透控速过程逐渐转变为体扩散过程,使实验初期渗透率显著升高;二是氢渗透过程中,合金膜存在再结晶现象,导致晶粒细化,增加了晶界扩散占比,使氢原子体扩散系数变大。

The unstable property of hydrogen permeation of Pd8Y0.23Ru alloy membrane at the beginning of permeation was investigated. The surface composition, morphology and phase structure were studied by XPS, SEM and XRD. The results indicated that there were two factors which caused the increasing of hydrogen permeability. Firsty, the carbonaceous impurities on the surface of Pd8Y0. 23Ru alloy membrane were removed during the hydrogen permeation process, which increased the speed of hydrogen gas dissociation and changed the rate-determining step to bulk diffusion of hydrogen atom, and remarkably increased the hydrogen permeability at the beginning of experiment. Secondly, recrystallization happened during the hydrogen permeation, which refined the grains, and increased the ratio of grain boundary diffusion which cause a bigger bulk diffusion coefficient.