Study of Metal Hydrides with High Hydrogen Composition using Quantum Beams Techniques

2014 Fiscal Year Final Research Report

• Project/Area Number: 24241032
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Quantum beam science
• Research Institution: Tohoku University
• Principal Investigator: AOKI Katsutoshi 東北大学, 金属材料研究所, 上級研究員 (30356331)
• Co-Investigator(Kenkyū-buntansha): HATTORI Takanori 日本原子力研究開発機構, J-PARCセンター, 研究主幹 (10327687) ; MACHIDA Akihiko 日本原子力研究開発機構, 量子ビーム応用研究部門, 研究副主幹 (70354983) ; MATSUO Motoaki 東北大学, 金属材料研究所, 講師 (20509038)
• Co-Investigator(Renkei-kenkyūsha): KATAYAMA Yoshinori 日本原子力研究開発機構, 量子ビーム応用研究部門, 研究主席 (20224462) ; SAITOH Hiroyuki 日本原子力研究開発機構, 量子ビーム応用研究部門, 研究副主幹 (20373243) ; SANO Asami 日本原子力研究開発機構, 量子ビーム応用研究部門, 研究員 (30547104) ; ENDO Naruki 日本原子力研究開発機構, 量子ビーム応用研究部門, 博士研究員 (40611893) ; OTOMO Toshiya 高エネルギー加速器研究機構, 物質構造科学研究所, 教授 (90270397) ; IKEDA Kazutaka 高エネルギー加速器研究機構, 物質構造科学研究所, 特任準教授 (80451615) ; OSHITA Hidetoshi 高エネルギー加速器研究機構, 物質構造科学研究所, 特任助教 (00625163) ; FUJIHISA Hiroshi 産業技術総合研究所, 計測フロンテイア研究部門, 主任研究員 (90357913)
• Research Collaborator: SATO Toyoto 東北大学, 金属材料研究所, 助教 (20455851) ; SUGIMOTO Hidehiko 中央大学, 理工学部, 教授 (00187668)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 中性子回折 / 放射光X線回折 / 高温高水素圧 / 金属水素化物 / 高水素組成 / サイト占有率

Outline of Final Research Achievements

A deutrization cell for high-pressure neutron diffraction measurement has been developed and was applied to in situ obseravtion of the deuterization process of iron at pressures up to 10 GPa. In solid-solution face-centered cubic FeDx formed at 988 K and 6.3 GPa, deuterium atoms occupied the octahedral and tetrahedral interstitial sites of the metallattice with an occupancy of 0.532(9) and 0.056(5), respectively, which gave a deuterium composition x of 0.64. During the deuterization process, the metal lattice was found to expand sucessively and linearly with deuterium composition.
The phase boundary between the hydrogen rich phases EuHx-III and EuHx-IV was determined by X-ray diffraction and infrared absorption measurements over a temperature range of 300-600 K and a pressure range of 5-10 GPa. The III-IV phase transition was likely accompanied by hydrogen absorption and resulting valence change of Eu cation: EuHx(x=2.2, divalent)→EuHx (x=3, trivalent).

Free Research Field

高圧物質科学