Phase transformation of the La_0.7Mg_0.3Ni_2.8Co_0.5-H₂ system studied by in situ X-ray diffraction

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• 作者：Yujun Chai ; Kohta Asano ; Kouji Sakaki ; Hirotoshi Enoki ; Etsuo Akiba
• 关键词：Crystal structure ; Hydrogen storage ; In situ XRD ; Rietveld method
• 刊名：Journal of Alloys and Compounds
• 出版年：2009
• 出版时间：19 October 2009
• 年：2009
• 卷：485
• 期：1-2
• 页码：174-180
• 全文大小：1209 K

文摘

Phase transformation in the La_0.7Mg_0.3Ni_2.8Co_0.5-H₂ system along the hydrogen absorption and desorption pressure–composition isotherm was studied using in situ X-ray diffraction. La_0.7Mg_0.3Ni_2.8Co_0.5 consisted mainly of the Ce₂Ni₇-type La₃Mg(Ni,Co)₁₄ phase. In hydrogen absorption of the Ce₂Ni₇-type phase, the hydrogen solid solution and hydride phases coexisted. The solid solution phase transformed to the hydride phase with isotropic expansion of the crystal lattice. In hydrogen desorption, coexistence of the two phases was not observed and the crystal lattice consecutively reduced with reduction of the hydrogen content. Lattice strain in the Ce₂Ni₇-type phase in hydrogen desorption was higher than that in hydrogen absorption.