Formation of crystalline and amorphous hydrides by hydrogenation of C15 Laves phase YFe2

kiyoshi aoki, Haiwen Li, M. Dilixiati, Kazuhiro Ishikawa

Research output: Contribution to journalArticle

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Abstract

Formation conditions of crystalline (c-) and amorphous (a-) YFe2Hx hydrides during thermal analysis of C15 Laves phase YFe2 in a hydrogen pressure (0.1–5.0 MPa) at heating rates of 0.17 and 0.33 K/s have been investigated by XRD, Ar-DSC, TEM and hydrogen analysis. Hydrogen absorption, hydrogen-induced amorphization (HIA), the precipitation of BiF3-type YH3 and the decomposition of the remaining amorphous hydride into α-Fe + YH3 occur exothermally with increasing temperature. The peak temperature Tp for hydrogen absorption, HIA, and the decomposition of the remaining amorphous hydride show the negative pressure dependence, but that for the precipitation of the hydride shows the positive one. As a consequence of such pressure dependence, HIA overlaps with the precipitation of YH3 at 0.1 MPa H2 and 0.33 K/s. Formation conditions of c- and a-YFe2Hx are compared with those of the other C15 Laves phases RFe2 and the mechanism of HIA in C15 Laves phases RFe2 is discussed.
Original languageEnglish
Pages (from-to)2-6
JournalMaterials Science and Engineering A
Volume449-451
DOIs
Publication statusPublished - 2007

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Laves phases
Hydrides
Hydrogenation
hydrogenation
hydrides
Hydrogen
Crystalline materials
Amorphization
hydrogen
pressure dependence
Decomposition
decomposition
Heating rate
Thermoanalysis
thermal analysis
Transmission electron microscopy
Temperature
transmission electron microscopy
heating
temperature

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Formation of crystalline and amorphous hydrides by hydrogenation of C15 Laves phase YFe2. / aoki, kiyoshi; Li, Haiwen; Dilixiati, M.; Ishikawa, Kazuhiro.

In: Materials Science and Engineering A, Vol. 449-451, 2007, p. 2-6.

Research output: Contribution to journalArticle

aoki, kiyoshi ; Li, Haiwen ; Dilixiati, M. ; Ishikawa, Kazuhiro. / Formation of crystalline and amorphous hydrides by hydrogenation of C15 Laves phase YFe2. In: Materials Science and Engineering A. 2007 ; Vol. 449-451. pp. 2-6.
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T1 - Formation of crystalline and amorphous hydrides by hydrogenation of C15 Laves phase YFe2

AU - aoki, kiyoshi

AU - Li, Haiwen

AU - Dilixiati, M.

AU - Ishikawa, Kazuhiro

PY - 2007

Y1 - 2007

N2 - Formation conditions of crystalline (c-) and amorphous (a-) YFe2Hx hydrides during thermal analysis of C15 Laves phase YFe2 in a hydrogen pressure (0.1–5.0 MPa) at heating rates of 0.17 and 0.33 K/s have been investigated by XRD, Ar-DSC, TEM and hydrogen analysis. Hydrogen absorption, hydrogen-induced amorphization (HIA), the precipitation of BiF3-type YH3 and the decomposition of the remaining amorphous hydride into α-Fe + YH3 occur exothermally with increasing temperature. The peak temperature Tp for hydrogen absorption, HIA, and the decomposition of the remaining amorphous hydride show the negative pressure dependence, but that for the precipitation of the hydride shows the positive one. As a consequence of such pressure dependence, HIA overlaps with the precipitation of YH3 at 0.1 MPa H2 and 0.33 K/s. Formation conditions of c- and a-YFe2Hx are compared with those of the other C15 Laves phases RFe2 and the mechanism of HIA in C15 Laves phases RFe2 is discussed.

AB - Formation conditions of crystalline (c-) and amorphous (a-) YFe2Hx hydrides during thermal analysis of C15 Laves phase YFe2 in a hydrogen pressure (0.1–5.0 MPa) at heating rates of 0.17 and 0.33 K/s have been investigated by XRD, Ar-DSC, TEM and hydrogen analysis. Hydrogen absorption, hydrogen-induced amorphization (HIA), the precipitation of BiF3-type YH3 and the decomposition of the remaining amorphous hydride into α-Fe + YH3 occur exothermally with increasing temperature. The peak temperature Tp for hydrogen absorption, HIA, and the decomposition of the remaining amorphous hydride show the negative pressure dependence, but that for the precipitation of the hydride shows the positive one. As a consequence of such pressure dependence, HIA overlaps with the precipitation of YH3 at 0.1 MPa H2 and 0.33 K/s. Formation conditions of c- and a-YFe2Hx are compared with those of the other C15 Laves phases RFe2 and the mechanism of HIA in C15 Laves phases RFe2 is discussed.

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DO - https://doi.org/10.1016/j.msea.2006.02.239

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JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

SN - 0921-5093

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