High hydrogen permeability in the Nb-Zr-Ni eutectic alloy containing the primary body-centered-cubic (Nb, Zr) phase

摘要

Hydrogen permeability (Φ), i.e., the product of hydrogen diffusion coefficient (D) and hydrogen solubility (K), of the as-cast Nb_(40)Zr_(30)Ni_(30) (mol %) alloy has been investigated. This alloy is composed of the primary body-centered-cubic (bcc)-(Nb, Zr) and eutectic {(Nb,Zr)+ZrNi} phase and the chemical composition and the volume fraction of the primary phase are Nb_(89)Zr_8Ni_3 and 40%, respectively. Φ of this alloy increases with increasing temperature and is 4.64 X 10~(-8) [mol H_2 m~(-1) s~(-1) Pa~(0.5)] at 673 K, which is 2.9 times larger than that of pure Pd. The present work indicates that Φ of the Nb-Zr-Ni alloys increases with increasing the volume fraction of the primary bcc-(Nb, Zr) phase.