Structural analysis for crystalline and amorphous RFe2D (R: Ho, Tb) by X-ray/neutron diffraction and reverse Monte Carlo modeling
摘要:
Atomic structures of crystalline (c-)HoFe2D3.6 and amorphous (a-)HoFe2D3.0 prepared by deuterium absorption of the C15 Laves phase compound HoFe2 were studied by X-ray and neutron diffraction techniques and these were compared with previous results for c- and a-TbFe2Dx. The structural parameters such as an interatomic distance and a coordination number are qualitatively in agreement with those for c- and a-TbFe2Dx. Namely, a marked difference was observed in the arrangement of metal atoms in a-HoFe2D3.0 compared to that in c-HoFe2D3.6 from interatomic distances and coordination numbers and there are clusters of Fe and Ho atoms in a-HoFe2Dx. RDF(r)s observed by the neutron diffraction indicated that the D atoms occupy tetrahedral sites consisting of 2Ho + 2Fe in c-HoFe2D3.6, while the D atoms occupy selectively tetrahedral sites consisting mainly of Ho atoms in a-HoFe2D3.0 because of strong affinity between D and Ho atoms.The reverse Monte Carlo (RMC) modeling method was employed to visualize a three-dimensional atomic arrangement by using combined X-ray and neuron diffraction data of RFe2Dx (R: Ho, Tb). Chemical fluctuation was visually observed in the RMC configurations. Moreover, it was found that about 40% of the D atoms occupy sites consisting of 4R. (C) 2004 Elsevier B.V. All rights reserved.
Hydrogen-induced amorphization in C15 Laves phases RFe2
作者:M. Dilixiati、K. Kanda、K. Ishikawa、K. Aoki
DOI:10.1016/s0925-8388(01)01923-5
日期:2002.5
Abstract C15Lavesphases RFe2 (R=Y, Ce, Sm, Gd, Tb, Dy, Ho and Er) were thermally analyzed to elucidate the conditions of hydrogen-inducedamorphization (HIA) using a pressure differentialscanning calorimeter (PDSC) in a hydrogen atmosphere. Hydrogen absorption in the crystalline state, hydrogen-inducedamorphization (HIA), precipitation of RH2 and decomposition of the remaining amorphous phase into
The standard enthalpies of formation of some binary intermetallic compounds of lanthanide–iron systems by high temperature direct synthesis calorimetry
作者:S.V. Meschel、P. Nash、Q.N. Gao、J.C. Wang、Y. Du
DOI:10.1016/j.jallcom.2012.11.035
日期:2013.3
formation of some binary and ternary shape memory alloys, which have established technological application, have also been measured. These are: Terfenol-D (−1.5 ± 3.1), Samfenol (−13.6 ± 3.1), Galfenol (−10.4 ± 2.8); Nd 2 Fe 14 B (−9.6 ± 3.2). The values are compared with predicted values of the semiempirical model of Miedema and Coworkers and with predictions by ab initio calculations. We will present
摘要 通过高温直接合成量热法在 1373 ± 2 K 下测量了一些镧系元素-铁系金属间化合物的标准生成焓。 报告了以下以 kJ/mole 原子为单位的结果: Ce 2 Fe 17 (-1.6 ± 2.8); Pr 2 Fe 17 (-0.2 ± 3.0);Nd 2 Fe 17 (-3.0 ± 2.7);Sm 2 Fe 17 (-3.1 ± 3.2);GdFe 2 (-2.4±3.0);HoFe 2 (-2.6 ± 3.3);ErFe 2 (-1.9 ± 3.0);TmFe 2 (-2.2 ± 2.8);LuFe 2 (-3.6 ± 3.1)。一些已确立技术应用的二元和三元形状记忆合金的标准形成焓也已被测量。它们是:Terfenol-D (-1.5 ± 3.1)、Samfenol (-13.6 ± 3.1)、Galfenol (-10.4 ± 2.8);Nd 2 Fe 14 B (-9.6 ±
Effects of rare-earth substitution in : mixed-valence and magnetic properties
作者:C C Tang、Y X Li、J Du、G H Wu、W S Zhan
DOI:10.1088/0953-8984/11/8/015
日期:1999.3.1
The lattice parameters and magneticproperties of (R = Ho, Er) have been investigated. The deviation of the lattice parameters from Vegard's law indicates that the Ce valence in both systems fluctuates with the concentration of the dopant R. This fluctuation is directly relevant to the degree of localization of Ce 4f electrons, and is independent of the atomic size of the dopant element. The observed
已经研究了 (R = Ho, Er) 的晶格参数和磁性。晶格参数与 Vegard 定律的偏差表明,两个系统中的 Ce 价数都随着掺杂剂 R 的浓度而波动。这种波动与 Ce 4f 电子的局部化程度直接相关,并且与原子尺寸无关。掺杂元素。观察到的变磁跃迁已经从带图中的描述中进行了分析。Ce 从混合价态到局域态的价态波动增加了 Ce 和 Fe 离子的矩以及居里温度。混合价态的变化也会影响 Ce-Fe 耦合的性质。
The 773 K isothermal section of the phase diagram of the Ho-Co-Fe ternary system was investigated by using X-ray diffraction technique, metallographic analysis and scanning electron microscopy with energy dispersive analysis. The isothermal section of the ternary system consists of 6 three-phase regions, 16 two-phase regions and 11 single-phase regions. Three pairs of corresponding compounds of Ho-Co and Ho-Fe systems, i.e., Ho(2)Co(17) and Ho(2)Fe(17), HoCo(3) and HoFe(3), HoCo(2) and HoFe(2), form a continuous series of solid solution. At 773 K the compound Ho(6)Fe(23-x)Co(x) was found to have a wide homogeneity range from 0 to 29 at.% Co. The maximum solid solubilities of Fe in Co, Ho(2)Co(7), Ho(12)Co(7) and Ho(3)Co were determined to be about 10, 9, 2 and 5 at.% Fe, respectively. The maximum solid solubility of Co in Fe is found to be 78 at.% Co. (C) 2010 Elsevier B.V. All rights reserved.
Burnasheva, V. V.; Ivanov, A. V.; Semenenko, K. N., Inorganic Materials, 1978, vol. 14, p. 1017 - 1021
作者:Burnasheva, V. V.、Ivanov, A. V.、Semenenko, K. N.