12333-67-4Relevant academic research and scientific papers
The standard enthalpies of formation of some intermetallic compounds of transition metals by high temperature direct synthesis calorimetry
Meschel,Kleppa
, p. 143 - 149 (2006)
The standard enthalpies of formation of some intermetallic compounds of transition metals have been measured by high temperature direct synthesis calorimetry at 1373 ± 2 K. The following results (in kJ/mol of atoms) are reported:{A formula is presented}. The values are compared with some earlier experimental results obtained by EMF and by calorimetry. They are also compared with the predicted values of Miedema and co-workers. We will present a systematic picture of how the enthalpies of formation may be related to the atomic number of the transition metal.
Hydrogen sorption of Mg-based mixtures elaborated by reactive mechanical grinding
Bobet,Chevalier,Song,Darriet,Etourneau
, p. 292 - 296 (2002)
The use of mechanical grinding (MG) under H2 of magnesium powder improves the hydrogen sorption properties. The hydrogenation of Mg starts in situ during the milling process that allows suppressing the activation procedure generally requested for Mg. The effects of the addition of various elements or compounds have been studied. The hydriding is a two-step process: nucleation and diffusion. A direct relationship exists between the nucleation duration and the specific surface. A critical milling time exists below which the diffusion process is improved and above which no further improvement is observed (the maximum internal stress in the powder is also reached at this critical time). The diffusion is controlled by the number of crystallites per particle that can be reduced by increasing the milling time up to 10 h. The addition of Co (catalyst), YNi (hydrogen pump) or oxides (abrasive element and nucleation centre) leads to an improvement of the hydrogen sorption properties (but a strong dependence upon the milling time is reported). Finally, the sorption properties of our mixtures are comparable with thus reported for MgH2-metal mixtures.
Coexistence of localized and (induced) itinerant magnetism and heat-capacity anomalies in Gd1-xYxNi alloys
Mallik,Paulose,Sampathkumaran,Patil,Nagarajan
, p. 8369 - 8373 (1997)
The results of magnetization (A/), electrical resistivity (p), and heat-capacity (C) measurements for the alloys, Gd1-xYxNi, are reported. The x-ray-diffraction patterns indicate that there is a change in the crystal structure from CrB-type to FeB-type orthorhombic structure for increasing x near Jt=0.4. GdNi has been known to order ferromagnetically at 70 K and the observed jc dependence of Tc and 6p proves that the strength of Gd-Gd exchange interaction is enhanced by a factor of about 1.5 in the FeB structure. The A/ data suggest that there is an excess moment for the Gd-rich alloys. The observed magnetization behavior is taken as an evidence to show that there is coexistence of localized magnetism (from Gd) and itinerant ferromagnetism of induced-type, presumably from Ni 3d band. There is an enhancement of C with decreasing temperature above TC oyer a wide temperature range presumably due to short-range order effects in these alloys.
Preliminary characterization of the intermetallic `YNi' obtained by both mechanical grinding and alloying
Nakhl,Chevalier,Bobet, J-L.,Darriet
, p. 94 - 100 (2000)
The intermetallic compound YNi and the (Y+Ni) mixture were submitted to a high-energy milling process under argon atmosphere. X-ray powder diffraction and microprobe analysis revealed in both cases the formation of a new phase `YNi'. Its structural properties were different from those of the YNi as-cast sample (orthorhombic FeB type) and presented some similarities with GdNi (orthorhombic CrB type) milled under the same conditions. The application of isostatic pressure on the YNi as-cast sample gives a comparable result. This non-equilibrium material `YNi' still exists even after annealing treatments performed up to 873 K. The presence of air during milling leads to the formation of a mixture of (oxy)nitride Y(O,N) and Ni metal and the new phase `YNi' is not synthesized under such conditions. Also, the influence of the milling process on the magnetic properties of similar compounds such as GdNi and ErNi is discussed.
Isothermal section of the phase diagram of the ternary system Y-Ni-V at 773 K
Pan, Shunkang,Zhou, Huaiying,Zhou, Qin,Yao, Qingrong,Wang, Zhongmin
, p. 119 - 121 (2009)
The isothermal section of the phase diagram of the ternary system Y-Ni-V at 773 K was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. It consists of 16 single-phase regions,
Improvements of hydrogen storage properties of Mg-based mixtures elaborated by reactive mechanical milling
Bobet,Chevalier,Song,Darriet
, p. 570 - 574 (2003)
The influence of mechanical grinding under hydrogen (Reactive Mechanical Grinding=RMG) on the chemical properties (crystallographic and phase composition) and on the hydrogen storage properties of Mg-based mixtures is examined. Different additives were st
Y-Ni-Bi and Ho-Ni-Bi Systems
Mozharivskii,Kuz'ma,Sichevich
, p. 707 - 710 (2008/10/08)
The 723-K sections of the Y-Ni-Bi and Ho-Ni-Bi phase diagrams are studied by x-ray diffraction. The compounds HoNiBi, Y5Ni2Bi, Ho5Ni2Bi, ～Y67Ni38Bi5, ～Y5NiBi2, and ～Ho5NiBi2 are identified for the first time. Crystallographic data for these ternary compounds are presented.
