Isothermal section at 800°C of the Gd-Fe-Ge ternary system

Asian Journal of Chemistry, 2016

The isothermal section of the phase diagram of the Gd-Fe-Ge ternary system at 800 °C was investigated by X-ray powder diffraction and scanning electron microscope-energy dispersive X-ray spectroscopy. Three intermediate solid solutions have been identified or confirmed: one lacunaire GdFexGe2 (CeNiSi2-type of structure space group P6/mmm) and two by substitition GdFe4-xGex (AlB4-type of structure space group I4/mmm) and GdFe12-xGex (YCo6Ge6-type of structure space group P6/mmm) and one ternary compound Gd117Fe52Ge112 (Tb117Fe52Ge112-type of structure space group Fm-3m). The magnetic properties of Gd117Fe52Ge112 compound is ferromanetic at 89 K have been studied. The 800 °C phase diagram of this system consists of 20 three-phases regions.

2021

The isothermal section of the phase diagram of the Gd–Cr–Ge ternary system was constructed at 1070 K over the whole concentration range using X-ray diffractometry, metallography and electron microprobe (EPM) analysis. Three ternary compounds are realized in the Gd–Cr–Ge system at the temperature of annealing: Gd117Cr52Ge112 (Tb117Fe52Ge112 structure type, space group Fm-3m, Pearson symbol cF1124, a = 2.8971(6) nm), GdCr6Ge6 (SmMn6Sn6 structure type, space group P6/mmm, Pearson symbol hP16, a = 0.51797(2), c = 0.82901(4) nm) and GdCr1-хGe2 (CeNiSi2 structure type, space group Cmcm, Pearson symbol oS16, a = 0.41569(1)-0.41593(8), b = 1.60895(6)-1.60738(3), c = 0.40318(1)-0.40305(8) nm). For the GdCr1-xGe2 compound the homogeneity range was determined (x=0.73 – 0,69).

Journal of Alloys and Compounds, 2002

The title ternary compounds have been thoroughly studied by X-ray diffraction, both on powders and single crystals. The already reported GdScGe does not form exactly at the equiatomic composition but with a stoichiometry slightly richer in Gd: Gd Sc Ge; it 1.02 0.98c rystallizes with the tetragonal CeScSi-type (ordered La Sb-type, space group I4 /mmm) with a54.261(1) and c515.593(5) A. 2G d Sc Ge is hexagonal, Mn Si-type (space group P6 /mcm), with cell parameters a58.276(5) and c56.116(6) A. Magnetic 2.38 2.62 3 5 3 3 measurements show that Gd Sc Ge undergoes a ferromagnetic transition at T 5350 K, whilst no evidence of long range magnetic 1.02 0.98 c ordering has been detected for Gd Sc Ge from 1.5 to 60 K, as deduced by preliminary heat capacity data.

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde), 2012

Phasee quilibriaof the Gd-Nibinary and Mg-Ni-Gd ternary systemsw erecriticallyinvestigated using equilibrated alloys and differentialscanning calorimetermeasurements.The phasediagramofthe Gd-Nibinary system wasu pdated from scanning electron microscopyw ithe nergy-dispersiveX-rayspectrometry,X-raydiffraction,a nd differentialscanning calorimeterresults obtained on binary samplesovert he entirecomposition range. Majorchanges made in the presentworkinclude the absenceofthe Gd 3 Ni 2 and GdNi 4 compoundsand the congruentmelting pointof the GdNicompound. Ani sothermalsection of the Mg-Ni-Gdternary system at6 73 Kwasconstructed from the investigationson 22 ternary alloys.Intotal,sixt ernary compoundsw erei dentified in thisw ork,three of which wereobserved tocrystallizeinthe Cu 4 MgSn(s 1),Mo 2 FeB 2 (s 2),and Ru 4 Al 3 B 2-type (s 3)structures,respectively.Asin most of the Mg-rare-earthm etal-transition metalternary systems,along-period-stacking ordered phasewasidentified tohavean18Rstructureand amelting temperatureof 806 K.Noticeable solid solubility of Nii nthe Mg 5 Gdand Mg 3 Gdbinary compoundswasobserved.

International Journal of Thermophysics, 2019

In this study, the phase diagram of the ternary Ag-Bi-Ge system was thermodynamically assessed and experimentally investigated, which to our knowledge has not been previously done. Differential thermal analysis (DTA), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS) and X-ray powder diffraction (XRD) were applied in order to experimentally assess three vertical sections and two isothermal sections at 200 °C and 400 °C of the Ag-Bi-Ge system. Results of the SEM-EDS and XRD analysis revealed existence of (Ge), (Ag) and (Bi) solid solution phases and absence of any ternary phases. Crystal structures of the identified phases and their corresponding lattice parameters were determined by XRD technique. Phase transition temperatures, including liquidus, solidus and temperature of an invariant reaction, were determined by means of DTA. Thermodynamic calculation of the Ag-Bi-Ge ternary phase diagram was carried out on the basis of optimized thermodynamic parameters for the constitutive binary systems acquired from the literature. Calculated liquidus projection of the Ag-Bi-Ge system and the determined invariant reactions are presented in the study as well. A close mutual agreement between the experimental results and the calculated phase equilibria was obtained.

ChemInform, 2010

Materials Science- …, 2008

Properties of the GdFeAl compounds crystallizing in the cubic MgCu 2-type structure as well as in hexagonal MgZn 2-type structure have been compared. The electrical resistivity, ac susceptibility and magnetization in function of temperature revealed relatively high magnetic ordering temperature, ca. 200 K. The differences in magnetization were observed for samples crystallizing in two different crystallographic structures. The magnetic moments measured at 4.2 K and up to140 kOe are very far from the value of the magnetic moment of a free Gd ion. The magnetic moments of cubic and hexagonal phases are 1.1 μ B and 1.7 μ B , respectively.

Journal of Alloys and Compounds, 2011

The isothermal section of the phase diagram of the Al-Dy-Ge ternary system at 673 K has been investigated by X-ray powder diffraction and scanning electron microscope equipped with energy dispersive X-ray spectroscopy in backscattered electron imaging modes. The existence of thirteen binary compounds including Dy 3 Ge 4 in the system Dy-Ge has been confirmed. Four ternary compounds, namely AlDyGe, Al 3 Dy 2 Ge 4 , AlDy 2 Ge 3 , and AlDy 2 Ge 2 were observed, and five new ternary compounds, i.e., Al 0.33 DyGe Ge 7+x (x ≤ 0.7), and one pseudo-binary compound Al 3−x DyGe x were found in this system at 673 K. The maximum solid solubility of Ge in the pseudo-binary compounds Al 3−x DyGe x is about 7.5 at.% with x = 0.3 at 673 K.

2011

In the course of an investigation of solid solutions with RFe1-xGe2 (R = Gd, Er) stoichiometry we have isolated two new phases. Their compositions are GdFe0.37Ge2 and ErFe0.27Ge2, and they have been synthesized by arc melting of pure components and studied by means of X-ray diffraction, SEM analysis and magnetic measurements. They crystallize in the orthorhombic space group Cmcm, with defect CeNiSi2-type structures. Magnetic susceptibility measurements performed in the temperature range 2–300 K showed conventional Curie-Weiss paramagnetic behaviour for both compounds above 25 K. At low temperature, magnetic susceptibility data revealed magnetic phase transitions.

Hyperfine Interactions, 1985

Three crystallographically different structures of (Fet_xVx) 3 Ge have been studied by STFe M6ssbauer spectroscopy. The hexagonal phase, stable for low values of x, is ferromagnetic with the spins parallel to the c-axis above a critical temperature, where a spin flip to the c-plane takes place. A V/Fe substitution in the near surrounding of an iron atom leads to a decrease in the isomer shift of-0.02 mm/s and an estimated reduction in the magnetic moment of 0.31 #B from 2.07 #B" A result for the intermediate cubic closed packed structure is that V populates only one type of metal sites. Furthermore, from similarities with a-Fe the average value of the change in isomer shift is found to be + 0.075 mm/s and + 0.02 mm/s per Ge/Fe substitution in the 1 nn and 2 nn shells, respectively. The spin polarization effect on the magnetic hyperfine field for iron is-8.6%,-0.4%, and-0.6% per Ge/Fe (1 nn), Ge/Fe (2 nn) and V/Fe (3 nn) substitutions, respectively. The simple cubic compound (Feo.7V0.3) 3 Ge is non-magnetic down to at least 5 K. Here a decrease in the isomer shift of-0.05 mm/s is found for a V/Fe (1 nn) substitution. magnetic DOI9 and DO 3 alloys. Recently, studies of a local interaction model of the ternary system (Fel_xTx)3Si (T = Ti, V, Cr, Mn, Co and Ni) have been published by Burch et al. [2] and Niculescu et al. [3]. This phenomenological model is based on a short-range interaction approach involving contributions from the first neighbour shell. In con-*On leave from the