Hydrogen absorption properties of Ce23Mg4Ni7 alloy at medium vacuum

Abstract

Ce–Mg–Ni alloys have a high affinity for hydrogen, and are typical examples of compounds that form hydrides. These hydrides may be formed in medium vacuum by using a hydrogen getter. In this study, Ce23Mg4Ni7 ternary alloy was fabricated by vacuum induction melting. The hydrogen absorption kinetics of the alloy were tested using an automatic Sievers device, and its hydride microstructure was observed via a transmission electron microscopy (TEM). The results indicate that the ternary phase, Ce23Mg4Ni7, is the main phase of the alloy, and the alloy absorbed hydrogen to form a Ce23Mg4Ni7Hx hydride. Under a hydrogen pressure of 5000 Pa at 50 °C, the equilibrium pressure of the system can be reduced to less than 10 Pa. By the eighth time of backfilling to compensate for hydrogen, the equilibrium pressure is reduced to 1 × 10−2 Pa. The Langmuir absorption equation was used to fit the hydrogen absorption results of the alloy, and it was shown that the saturated hydrogen absorption capacity of the alloy is 55.72 mL, and the absorption coefficient is 0.0078 at 50 °C.