Effects of catalytic surface layer on Zr-based alloy getters for hydrogen absorption

Abstract

Hydrogen sorption characteristics of Zr-based alloy getters fabricated in the forms of bulk were investigated. Non-evaporable getters (NEGs) have been widely used in vacuum devices, but thermal activation process at high temperature and high vacuum environment is inevitably required for efficient sorption rate. In order to solve this problem and improve sorption kinetics, we developed and characterized Ni-coated NEGs. Ni-coated NEGs show good gettering performance and fast sorption kinetics without any activation process, compared to conventional Zr-based NEGs. It is mainly caused by the catalytic effect of surface Ni layer. Surface Ni plays an important role as a catalyst that enables hydrogen to dissociate on surface more easily and also as a protection layer against oxidation. Consequently, Ni-coated NEGs can be easily applicable to vacuum devices because those need not go through the activation process and show fast hydrogen sorption kinetics.