多孔陶瓷基体渗透率对Pd膜透氢性能的影响

Effects of permeability of porous ceramic substrates on hydrogen permeation performance of palladium membranes

采用化学镀法在气体渗透率不同的多孔陶瓷基体上制备厚度均为5μm的Pd膜,研究了基体渗透率对Pd膜透氢性能的影响。在N2渗透率分别为2 470、1 390 m3/(m2.h.MPa)的基体上制备的Pd膜透氢过程均符合Siev-ert定律,压力指数n值为0.5,即氢在Pd膜中的体相扩散为H2透过Pd膜的速率控制步骤;而对于在N2渗透率为610 m3/(m2.h.MPa)的基体上制备的Pd膜,压力指数n值为0.8,同时Pd膜的H2通量增加幅度随着温度的升高而变小,说明基体的传质阻力对Pd膜透氢速率产生影响。考察了基体渗透率对Pd膜稳定性的影响,发现在渗透率较低的基体上制备的Pd膜稳定性较好。

Palladium membranes were prepared on porous ceramic substrates with different permeabilities via electroless plating,and all the thicknesses of the membranes were 5 μm.The effects of permeability of substrates on the performance of palladium membranes were studied.For palladium membranes prepared on substrates N2 permeabilities were 2 470 m3/（m2·h·MPa） and 1 390 m3/（m2·h·MPa）,respectively,the hydrogen permeation obeyed sievert law with the pressure exponent n=0.5,thus bulk diffusion was the rate-controlling step;for the palladium membranes prepared on substrates with N2 permeability of 610 m3/（m2 h MPa）,the pressure exponent n=0.8,and the increasing extent of H2 flux was lower with temperature increasing.It was showed that the diffusion resistance of substrate influenced the permeation performance.The effects of porous substrates on stability of palladium membranes were investigated.Results indicated that the palladium membranes prepared on substrates with low permeability had a better stability at higher temperatures.