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开展了Nb-Ni-Ti体系氢分离合金膜的结构和渗氢性能研究。采用XRD、SEM分析膜片的相结构和组织特征,利用Devanathan-Stachurski双电解池法测定膜片的氢扩散系数,考察膜片厚度、成分和结构组织对其氢扩散系数的影响。实验结果表明:氢分离膜的氢扩散系数均随膜片厚度的增加而增大。制备的Nb-Ni-Ti体系合金膜都具有两相结构,即先析出相(bcc-Nb(Ni,Ti)固溶体)和共晶相(bcc-Nb(Ni,Ti)+β2-NiTi),个别成分点有少量的第三相NiTi2生成。膜片成分和组织结构对氢扩散系数影响显著,当合金中先析出固溶体相比例增加时,合金中的氢扩散系数也随着增大,而Ni,Ti含量的变化引起共晶相变化,NiTi相及NiTi2相都不同程度增加了共晶相的相比例而引起氢扩散系数的降低,但同时在结构上改善了合金在吸氢膨胀过程中发生的氢脆现象。氢在Nb-Ni-Ti体系氢分离膜中的扩散系数在10-9数量级范围。
The structure and hydrogen permeation properties of Nb-Ni-Ti hydrogen separation alloy films were investigated. The phase structure and microstructure of the membrane were analyzed by XRD and SEM. The Devanathan-Stachurski double cell method was used to measure the hydrogen diffusion coefficient of the membrane, and the influence of the thickness, composition and structure of the membrane on the hydrogen diffusion coefficient was investigated. Experimental results show that the hydrogen diffusion coefficient of hydrogen separation membrane increases with the increase of membrane thickness. The prepared Nb-Ni-Ti system alloy films all have a two-phase structure, that is, the bcc-Nb (Ni, Ti) solid solution and the eutectic phase bcc-Nb (Ni, Ti) + β2-NiTi are precipitated first, A small amount of individual components point a third phase NiTi2 generation. The composition and microstructure of the film have a significant effect on the hydrogen diffusion coefficient. When the proportion of precipitated solid solution in the alloy increases, the hydrogen diffusion coefficient of the alloy also increases, while the change of Ni and Ti content causes the eutectic phase transformation. The NiTi Phase and NiTi2 phase all increase the phase ratio of eutectic phase to some extent and cause the decrease of hydrogen diffusion coefficient, but at the same time, the hydrogen embrittlement phenomenon during the process of hydrogen absorption and expansion is improved. The diffusion coefficient of hydrogen in the hydrogen separation membrane of Nb-Ni-Ti system is in the order of 10-9.