Hydrogen and nitrogen absorption properties of Ce-added Zr2(Fe1–xNix) alloys

Abstract

To improve the nitriding resistance of Zr2Fe alloy, the Ce-added Zr2(Fe1–xNix) (x = 0, 0.15, 0.3, 0.5) alloys were prepared by magnetic levitation melting method. The effects of Ni substitution for Fe on the phase structure, hydrogen and nitrogen absorption properties of the alloys were investigated by X-ray diffraction, scanning electron microscopy and p-c isotherm measurements. The experimental results show that Ni substitution can effectively inhibit the formation of both α-Zr and ZrFe2 phases and promote the formation of C16 structure Zr2(Fe, Ni) phase, causing Ni-substituted alloys to exhibit low nitrogen absorption rate and capacity. At 623 K under 0.5 MPa nitrogen pressure, the nitrogen absorption capacity of Ce-added Zr2(Fe0.5Ni0.5) alloy reaches to 0.8 mL/g, much lower than that of Zr2Fe alloy (1.5 mL/g). Ni substitution decreases the crystal cell volume of the C16 Zr2(Fe, Ni) phase, resulting in an increase in the hydrogen absorption equilibrium pressure. At 623 K under 0.05 MPa hydrogen pressure, the hydrogen absorption capacity decreases from 1.46 wt% of Zr2Fe alloy to 1.41 wt% of Ce-added Zr2(Fe0.5Ni0.5) alloy.