Binary C14 Laves phase alloy CaMg2 is expected to absorb hydrogen more than 6 mass%, when the H/M ratio reaches 2. We have found that the binary CaMg2 did not absorb hydrogen at ambient temperature and hydrogen pressure but Ni added CaMg1.8Ni0.2 which is also C14 Laves phase absorbed 6.0mass% of hydrogen at room temperature. CaMg 1.8Ni0.2 formed hydrides of Mg and Ca, and the C14 Laves phase disappeared. Hydrogen desorption was not observed from hydrogenated CaMg1.8Ni0.8. (Ca0.8La0.2)Mg 2.2Ni0.1 absorbed 5.1mass% hydrogen and H/M ratio reached 1.8 at room temperature. After hydrogenation, the lattice of the Laves phase expands 4% in α-axis and 3% in c-axis. The volume expansion is 13%. The Laves phase structure is kept and hydrogen was absorbed in the lattice. The hydride of (Ca0.8La0.2Mg2.2Ni0.1 decomposed from 470 K with increase at temperature and hydrogen was released from the products of decomposition from 610 K.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering