化学镀Pd膜的结构及其对Nb-Ti-Ni体系氢分离膜的氢渗透催化研究

Structural Characterization of Electroless Deposited Pd Coat and Its Catalytic Effect on Hydrogen Permeation of Nb-Ti-Ni Alloy Membranes

采用碱性化学镀在Nb-Ti-Ni合金膜片表面和载玻片上沉积了Pd膜,利用X射线衍射(XRD),能谱(EDS)、扫描电子显微镜(SEM),示差扫描量热仪(DSC)等手段对Pd沉积膜的相结构、成分、形貌及热稳定性进行了分析。结果表明,制备的Pd沉积膜为非晶态结构,膜层呈现球状颗粒密排沉积形态,颗粒尺寸在1μm左右,膜中的P含量在3%～4%(质量分数,下同)。膜的热稳定性研究表明,在经675K热处理后,膜层仍保持其初始的颗粒密排沉积特征,随着温度的升高,颗粒尺寸有轻微增大的趋势,出现Pd相和Pd6P相。电化学测试结果表明,制备的非晶态Pd膜可显著提高合金膜片的氢渗透电流密度,相应的氢扩散系数增大,而非晶膜层经热处理后,其氢扩散系数有较明显的降低。

Electroless deposited Pd coats have been prepared on Nb-Ni-Ti alloy membranes and glass substrates,XRD,DSC,SEM and EDX analysis were employed to determine the phase compositions,thermal stabilities and surface morphology of Pd deposited coats in this paper.It revealed that prepared Pd coat appeared to be a particle-deposited surface image with amorphous microstructure,consisting of numerous spherical particles（1 μm or so） arranged in single-layer form,the content of P in the coats is about 3 wt%-4 wt%.Such coat can keep its original appearance,but slight increase of particle size,strong intensity of Pd phase and Pd6P have been observed after heat treatment at 675 K.Hydrogen diffusion coefficient of Nb-Ni-Ti alloy membranes with original amorphous Pd coat is quite higher than that of samples without Pd coat,as well as that of samples with Pd coat after heat treatment at 675 K,indicating that prepared Pd coat has good catalytic effect on hydrogen permeation of Nb-Ni-Ti alloy membranes.