Showing papers in "Journal of The Less Common Metals in 1973"
TL;DR: In this article, it is shown that the work function of a metal is proportional to the chemical potential for electrons in Wigner-Seitz atomic cells; the proportionality factor is found to be about 1·4.
Abstract: It is demonstrated that a cellular model gives an excellent account of the heat of formation of binary alloys of 27 transition metals. The energy effects are described by two terms, the first representing the difference in electronegativity between the two types of atoms in an alloy and the second term reflecting the discontinuity in the density of electrons at the boundary between dissimilar Wigner-Seitz atomic cells. The electronegativity is expressed in a scale which closely resembles that of the experimental work functions of pure metallic elements.
The use of this scale also gives a clear insight into the heat effects which accompany the alloying of transition metals with non-transition metals. If the latter have p-electrons a negative term adds up to the heat of formation which apparently does not depend on the particular metals considered. As a result, simple rules for the alloying behaviour of transition metals are formulated which have an accuracy between 96 and 100%; the electronegativity concept is shown to apply also for hydrogen in metals.
The relation between the charge transferred per atom, ΔZa, and the difference in electronegativity, Δφ∗, is discussed quantitatively. As an example, the result for solid solutions of two transition metals is ΔZa = 1.2 (1 − ca)Δφ∗, where ca is the concentration of metal A. Our analysis supports the idea that the work function of a metal is, in principle, proportional to the chemical potential for electrons in Wigner-Seitz atomic cells; the proportionality factor is found to be about 1·4.
520 citations
TL;DR: In this article, the authors present a Zustandsdiagramme des Pd with Y, Sm, Gd, Dy, Ho and Er werden anhand thermoanalytischer, mikroskopischer und rontgenographischer Untersuchungen aufgestellt.
Abstract: Zusammenfassung Die Zustandsdiagramme des Pd mit Y, Sm, Gd, Dy, Ho und Er werden anhand thermoanalytischer, mikroskopischer und rontgenographischer Untersuchungen aufgestellt. Allgemein wird die Existenz von 7 intermetallischen Verbindungen nachgewiesen, von denen LnPd3, Ln4Pd5 und LnPd stets kongruent schmelzen. LnPd2. Ln2Pd3 und Ln3Pd2 entstehen durch peritektische Reaktionen. Ln5Pd2 schmilzt fur Ln = Y, Dy, Er kongruent und fur Ln = Sm, Gd, Ho inkongruent. Sm2Pd3 existiert nicht, Gd2Pd3 nur zwischen 1130° und 1160°C. Im System Sm-Pd tritt die sich peritektisch bildende Phase SmPd5 auf. Uber die Strukturen von LnPd3, LnPd. Ln3Pd2 und Ln5Pd2 werden Angaben gemacht.
123 citations
TL;DR: In this paper, the crystal structures of the 7:3 phases of the 8th Group RE-T systems have been investigated by metallographic and X-ray methods, and the occurrence of a Th7Fe3 phase was found in 25 systems.
Abstract: The crystal structures of the 7:3 phases of the RE-T systems, where T is an element of the 8th Group, have been investigated by metallographic and X-ray methods The occurrence of a 7:3 phase, of the Th7Fe3 structure type, was found in 25 systems A systematic investigation of the stability of this phase carried out for the RE-Ni and RE-Rh systems leads to the conclusion that in the binary systems with Ni its occurrence is restricted to the lighter RE elements (La, Ce, Pr and Nd), while in the systems with Rh the phase exists for every RE metal examined (La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) Crystallographic data at room temperature and magnetic properties in the temperature range 77–500 K for 25 compounds are reported
115 citations
TL;DR: In this article, a general scheme of precipitation is proposed, and the conditions defined under which each phase precipitates, and two non-equilibrium phases are shown to exist, their formation being dependent on the quenched-in vacancy population as in aluminium alloys.
Abstract: The precipitation behaviour of a binary Mg-0.5 at.% Nd alloy has been studied by electrical resistivity and electron microscope techniques. A general scheme of precipitation is proposed, and the conditions defined under which each phase precipitates. G.P. zones are shown to exist, their formation being dependent on the quenched-in vacancy population as in aluminium alloys; in addition, there are two further non-equilibrium phases, and the equilibrium precipitate. The morphology and structure of each of these phases has been investigated, and related to the good elevated temperature strength shown by this alloy.
104 citations
TL;DR: In this paper, the Curie temperature and the saturation magnetization of the pseudobinary system LaCo 5x Ni 5−5x have been determined as a function of composition and the variation of the lattice constants suggests an anisotropic magneto-volume effect accompanying the paramagnetic-ferromagnetic transition.
Abstract: The lattice constants, the Curie temperature and the saturation magnetization of the pseudobinary system LaCo 5x Ni 5−5x have been determined as a function of composition. The variation of the lattice constants suggests an anisotropic magneto-volume effect accompanying the paramagnetic-ferromagnetic transition. The hydrogen absorption capacity decreases markedly with x in the series LaCo 5x Ni 5−5x . The nature of the hydride phases corresponding to the various plateau pressures of the absorption isotherms has been studied by X-ray diffraction. The hydrogen equilibrium pressure at the first hydride is strongly reduced when x increases. Dependent on x one can discern two regions where this equilibrium pressure varies as In p = Cx + q , the absolute value for C being largest for small x values.
95 citations
TL;DR: The boundaries of the homogeneity regions of the phases SmCo 5, GdCo 5 and Gd 2 Co 17 have been determined by microscopic investigation as discussed by the authors, showing that at elevated temperatures the cohesiveness region of these phases extends to the Co-rich and Co-deficient side.
Abstract: The boundaries of the homogeneity regions of the phases SmCo 5 , GdCo 5 and Gd 2 Co 17 have been determined by microscopic investigation. At elevated temperatures the homogeneity region of the phases SmCo 5 and GdCo 5 extends to the Co-rich as well as to the Co-deficient side whereas the phases Gd 2 Co 17 and Sm 2 Co 17 show almost no Co solubility. A tentative diagram is presented for the phase relationships involved in the transition between the two allotropic forms of Gd 2 Co 17 . The occurrence of various types of microstructures in as-cast and annealed RCo 5 samples is explained in terms of the peculiar shape of the solvus of the RCo 5 homogeneity regions at high temperatures.
90 citations
TL;DR: The presence of the crystalline electric field is felt rather strongly by the 4 ¼ shells of Pr and Nd in this environment so that these materials are exchange enhanced ferromagnets as mentioned in this paper.
Abstract: RNiAl and RCuAl crystallize with the Fe 2 P structure. This structure type is less densely packed than the Laves phases. Most of these materials order ferro-magnetically at low temperature but ErNiAl and TmNiAl, which according to the de Gennes function should exhibit relatively weak ferromagnetism, are shown to be subtle metamagnets. The presence of the crystalline electric field is felt rather strongly by the 4ƒ shells of Pr and Nd in this environment so that these materials are exchange enhanced ferromagnets.
82 citations
TL;DR: In this paper, the authors used the Mossbauer spectra of R.E.XSn (X = Rh, Pd, Ir, Pt) for site assignment and showed that Yb is trivalent in these compounds.
Abstract: Crystallographic and Mossbauer studies have been made on new ternary equiatomic compounds R.E.XSn (X = Rh, Pd, Ir, Pt) which have a hexagonal crystal structure, isostructural with Fe2P ( D 3 3 h — P 6 2m ). A typical example is HoPtSn with a 0 = 7.418 ± 0.001 A , c a = 0.535 , and V M = 63.00 A . The X-ray analysis leads to the following site assignments: Ho located in 3(g) sites at x, 0, 1 2 ; Pt atoms in 1(b) at 0, 0, 1 2 and 2(c) at 1 3 , 2 3 ,0; and Sn atoms in 3(f) at x, 0, 0. The volume per formula weight of YbRhSn is intermediate between those of TmRhSn and LuRhSn which indicates that Yb is trivalent in these compounds. The 119Sn Mossbauer spectra at 295 K are symmetrical or slightly asymmetrical doublets which have been fitted to the model of site occupation given by the Crystallographic results for HoPtSn. An asymmetry in the spectrum at 295 K vanishes at 77.3 K for TbRhSn; this behavior is indicative of an anisotropic Debye-Waller factor. The isomer shift at 295 K is similar for all alloys; a typical value is + 1.8 mm/s (compared to + 2.6 mm/s for β-Sn). However, the quadrupolar coupling varies by a factor of two (0.34–0.70 mm/s). At 4.2 K TbRhSn and HoPtSn show asymmetric broadening which is interpreted as magnetic in origin.⧹At 77.3 K GdRhSn is broadened by 40% which may indicate magnetic order above this temperature.
70 citations
TL;DR: In this paper, the precipitation of the V3N phase in the α phase of V-N system has been investigated using transmission electron microscopy and diffraction, and the phase is shown to be c.p.h.
Abstract: The precipitation of the V3N phase in the α phase of the V-N system has been investigated using transmission electron microscopy and diffraction. This phase is shown to be c.p.h. in respect to metal atoms and the nitrogen atoms are ordered in an interpenetrating hexagonal structure. Precipitation proceeds by nucleation and growth of V3N particles in the α-phase. At a size of about 5000 A the growing particle causes plastic deformation of the matrix. Twins with K1 = {10.1} are present throughout the growth process and these are shown to result from restraints imposed by the matrix. The plate-like morphology of the V3N has a habit plane near {112}bcc. The orientation relationship is only approximately that of Burgers and is best described as (10·1)cph 11 (110)bcc, where (10·1)cph is the particular {10·1}cph plane which is also the twin plane in the particle. In this plane the close-packed directions are rotated by 2.4 ± 0.2 °. Energetic considerations relating to the precipitate shape and the orientation relationship are discussed.
67 citations
TL;DR: In this paper, the stability of double pseudobinary solid solutions with respect to phase separation was found to be dependent not only on the randomization energy, but also on the free energies of formation of the boundary phases.
Abstract: The stability of double pseudobinary solid solutions with respect to phase separation was found to be dependent not only on the randomization energy, but also on the free energies of formation of the boundary phases. Phase separations in such systems may therefore also occur when the boundary solutions behave ideally. The conditions for stability and the binodal and spinodal surfaces are derived and applied to the alloy system Ti-Mo-C-N. Predictions are made for V-Mo-C-N and other carbonitride systems. The results are discussed and the thermodynamic considerations generalized to include higher order systems. Possible applications of this new phenomenon in alloy development and studies of phase phenomena in higher order systems are outlined.
65 citations
TL;DR: The ternary alloy system Ti-W-C was investigated by means of melting point, differential-thermoanalytical, X-ray diffraction, and metallographic techniques on hot-pressed and heat-treated, alloy specimens and a phase diagram from 1500 °C through the melting range established as discussed by the authors.
Abstract: The ternary alloy system Ti-W-C was investigated by means of melting point, differential-thermoanalytical, X-ray diffraction, and metallographic techniques on hot-pressed and heat-treated, as well as melted, alloy specimens and a phase diagram from 1500 °C through the melting range established. Above 2530 °C, titanium monocarbide and the isomorphous cubic high temperature phase in the W-C binary system are completely miscible and the solid solution has a congruent (maximum-type) melting point of 3130 °C at the approximate composition (Ti0.54W0.44)C0.75. Below 2530 °C, the tungsten exchange in the cubic monocarbide is temperature-dependent and decreases to about 50 at.% at 1400 °C. The titanium exchange in W2C is less than 3 at.% at 1500 °C and reaches a maximum of 8 at.% at 2680 °C. In addition to the ternary congruent melting point, four reaction isotherms occur in the system: Two are pseudobinary eutectics, monocarbide + graphite at 3030 °C, and monocarbide + tungsten-rich metal alloy at 2700 °C; peritectic melting of the binary WC results in a class II reaction L + C⇄cubic monocarbide + WC(hex) at 2760 °C, and a fourth isotherm at 2680 °C is associated with a ternary eutectic between metal, monocarbide (B1), and W2C. Pseudobinary eutectic melting between the monocarbide and the metal phase is directly attributable to the large stability difference between titanium and tungsten carbide, and the measured tie line distribution in the two-phase range metal + monocarbide is in accordance with estimates from known thermodynamic values for the binary boundary phases. The phase behavior in pseudobinary monocarbide solutions is largely determined by the relative lattice size of the boundary carbides, except for systems (M, W)C1 − x (M = Ti, Zr, Hf, V). which show extra stabilization due to bonding effects.
TL;DR: The magnetic properties of rare earth-magnesium compounds with the CsCl structure have been determined in the temperature range 4.2-300 K with applied magnetic fields up to 18 kOe.
Abstract: The magnetic properties of rare earth-magnesium compounds with the CsCl structure have been determined in the temperature range 4.2–300 K with applied magnetic fields up to 18 kOe. There is a change in sign of the asymptotic Curie temperatures in going from compounds with light rare-earth elements to those with heavy rare-earth elements. The temperature dependence of the magnetization in the magnetically ordered region points to antiferromagnetism for the former compounds and to ferromagnetism for the latter compounds. For all compounds investigated the lattice constants have been determined.
TL;DR: The behavior of rare earth metals with cadmium has been studied for the following compositions: MCd 3, MCd 4, M 2 Cd 9~, MCd 6 and M 2Cd 17.
Abstract: The behaviour of all rare-earth metals with cadmium has been studied for the following compositions: MCd 3 , MCd 4 , M 2 Cd 9~ , MCd 6 and M 2 Cd 17 . The crystal structure of these phases has been determined together with that of ThCd 11 . A survey of all R.E.-Cd intermetallic compounds is given. Structural and geometrical relations among the types of structure occurring are examined.
TL;DR: The total dilatation of CeAl2 from 2.5 to 300 K was found to be similar to that of LaAl2, thus making the assumption of a Ce4+→Ce3+ transition unlikely as discussed by the authors.
Abstract: The total dilatation of CeAl2 from 2.5 to 300 K was found to be similar to that of LaAl2, thus making the assumption of a Ce4+→Ce3+ transition unlikely. A negative peak in the dilatation curve of CeAl2 coincides with the specific-heat peak at 3.36 K. A second transition occurs at 4.5–4.8 K. Magnetization measurements confirm the antiferromagnetism of CeAl2.
TL;DR: In this article, it was shown that when the atomic number of the components are two or more apart, there may be a very slight negative deviation from linearity which reaches a maximum at the composition where the b.c.d. first starts to form from the melt.
Abstract: The ErY, TbHo, TbEr, DyHo, DyEr and HoEr systems have been studied by thermal, X-ray and metallographic methods. It is known that these properties can be influenced significantly by the presence of non-metallic impurities. Therefore, these measurements were made on very pure metals prepared in this Laboratory and the alloys were carefully analyzed for all possible impurities. These systems are characterized by complete mutual solubility and within our experimental errors, no enrichment of one rare earth over the other was gbserved during solidification or transformation. The solidus and liquidus lines, therefore, fell on top of one another over the entire composition range. The addition of Er to Y or Y to Er lowers the melting point which reaches a minimum at 53 at.% Er. Alloys containing less than 53 at.% Er solidify to a b.c.c. lattice which transforms at lower temperatures to a h.c.p. lattice. Alloys with greater than 53 at.% Er crystallize directly to the h.c.p. solid solution. For the TbHo, TbEr, DyHo and DyEr systems, the melting point appears to decrease linearly with increasing at.% of the lower atomic numbered rare earth. However, when the atomic number of the components are two or more apart, there may be a very slight negative deviation from linearity which reaches a maximum at the composition where the b.c.c. first starts to form from the melt. This is especially evident in the DyEr system in which the negative deviation could be interpreted as a slight change in slope occurring at the composition where the b.c.c. first starts to form from the melt. The b.c.c. starts to form at 10 and 34 at.% Tb in the Tb-Ho and TbEr systems and at 25 and 50 at.% Dy in the DyHo and DyEr systems, respectively. The transformation temperature is lowered linearly from these points with increasing composition of the lighter rare earth to the transition temperature of the pure solute. The HoEr system has a linear variation of melting points with composition. The a and c lattice parameters vary linearly with composition within our experimental errors for the binary systems of adjacent elements. By the time the elements are four apart in the series, TbEr, a distinct deviation from linearity occurs in the plot of lattice constant versus composition which is positive for the a axis and negative for the c axis.
TL;DR: In this paper, the use of solid state electrolysis as a purification technique for the preparation of high purity gadolinium is described and assessed using ultra high vacuum and a double cycle technique.
Abstract: The utilisation of solid state electrolysis as a purification technique for the preparation of high-purity gadolinium is described and assessed. Using ultra high vacuum and a double cycle technique, the oxygen content in gadolinium has been reduced by two orders of magnitude and many other impurities reduced by significant amounts, yielding gadolinium of much higher purity and resistance ratio than previously reported. Additionally, large single crystals are often produced in the purified sample.
TL;DR: The magnetic structure of HoFe3 has been determined by powder neutron diffraction techniques as mentioned in this paper, and the moments of the holmium and the iron atoms are colinear, ferrimagnetically coupled, and parallel to the basal plane of the hexagonal structure.
Abstract: The magnetic structure of HoFe3 has been determined by powder neutron diffraction techniques. The moments of the holmium and the iron atoms are colinear, ferrimagnetically coupled, and parallel to the basal plane of the hexagonal structure. X-ray diffraction of the powder, oriented in a magnetic field, has shown that the easy direction of magnetization is the b-axis. Molecular field coefficients and average exchange fields for holmium and iron atoms have been calculated from the thermal variation of the magnetization and the paramagnetic susceptibility. The interactions between iron atoms are strong whereas the holmium-holmium and holmium-iron interactions are weak.
TL;DR: The crystal structure of the compounds CaP, SrP, CaAs, SrAs and EuAs has been determined from powder data as discussed by the authors, and these compounds crystallize with the Na 2 O 2 structure type, characterized by groups P 2 or As 2.
Abstract: The crystal structure of the compounds CaP, SrP, CaAs, SrAs and EuAs has been determined from powder data. These compounds crystallize with the Na 2 O 2 structure type, characterized by groups P 2 or As 2 . The magnetic susceptibility and the lattice constants of EuAs show that Eu is divalent in this compound. The corresponding phases BaP and BaAs do not exist.
TL;DR: The compound Gd5Pd2 has actually the composition Gd7Pd3 and crystallizes with the hexagonal Th7Fe3 structure type: space group P6 3 mc, a = 9.980 A and c = 6.216 A.
Abstract: The earlier reported compound Gd5Pd2 has actually the composition Gd7Pd3 and crystallizes with the hexagonal Th7Fe3 structure type: space group P6 3 mc, a = 9.980 A and c = 6.216 A . The compounds La7Pd3, Ce7Pd3, Pr7Pd3, Nd7Pd3 and Sm7Pd3 were found to be isotypic with Gd7Pd3.
TL;DR: In this paper, an intermediate form between the corundum structure and the high-temperature, high-pressure orthorhombic structure of Rh2O3 has been investigated by X-ray powder methods.
Abstract: The structure of the high-temperature, low-pressure form of Rh2O3 has been investigated by X-ray powder methods. This form is orthorhombic, with a = 5.1477 ± 2 A , b = 5.4425 ± 6 A , c = 14.6977 ± 11 A , Z = 8, Dobs = 8.06 g/cm3, Dcalc = 8.19 g/cm3 and space group Pbca — D152h (no. 61). The structure presented can be described as a stacking of layers, consisting of Rh2O3-units, of the corundum structure, cut parallel to (0112). This structure may be considered as an intermediate form between the corundum structure and the high-temperature, high-pressure orthorhombic structure of Rh2O3.
TL;DR: The calcium-mercury system has been investigated using thermal, micro-graphic and X-ray methods as mentioned in this paper, and the crystal structures of all compounds except CaHgx were determined.
Abstract: The calcium-mercury system has been investigated using thermal, micrographic and X-ray methods. Three compounds melt congruently: CaHg (961 °C), CaHg2 (746 °C) and Ca3Hg (523 °C). Six other compounds form peritectically: Ca2Hg(530 °C),Ca5Hg3(587 °C), Ca3Hg2(660 °C), CaHg3 (570 °C), CaHg3.6(264 °C) and CaHgx with 7 The crystal structures of all compounds except CaHgx were determined.
TL;DR: In this paper, the radii of rare earth metal rare-earth compounds were determined and the interatomic distances calculated and compared with corresponding data of MAg2Si2 compounds.
Abstract: MAu2Si2 type compounds of the LaEr rare-earth metals crystallize in the ThCr2Si2-type body-centered tetragonal structure. Lattice constants and atomic parameters were determined, and the interatomic distances calculated and compared with corresponding data of MAg2Si2 compounds. The radii R AU = 1.36 A and R ag = 1.18 A found are very close to the ionic radii of these atoms. The radii of silicon has the value of the atomic radius in the silver compounds and the covalent radius in the gold compounds.
TL;DR: In this article, ordering tendencies on crystallographic sites are studied by X-ray and neutron diffraction on compounds with a rare-earth basis with transition metals (Fe and Co) and Al.
Abstract: Ordering tendencies on crystallographic sites are studied by X-ray and neutron diffraction on compounds with a rare-earth basis with transition metals (Fe and Co) and Al. Materials studied in detail include Al substituted phases ErCo 2 , DyFe 2 , Tb 2 Fe 17 , and PrCo 5 , as well as ternary phases ErCoAl and DyFeAl. In all cases studied, the rare earths solely occupy one set of crystallographic sites. In rare-earth binaries with a transition metal basis, Al substitution takes place at random on transition metal sites. Ordering tendencies are observed in the homogeneous regions of ternaries, the most pronounced one being ErCoAl and LuCoAl which, at compositions corresponding to R 2 CoAl 3 , crystallize with a superstructure of the MgZn 2 type. A different type of ordering tendency is observed in the Fe analog ternaries.
TL;DR: In this article, the purification of calcium and barium was carried out by double ultra high vacuum "reactive distillation" of these metals in a molybdenum column and the distributions of all elemental impurities and molecular species in the starting materials and in various fractions of the distillate were determined with spark source mass spectrographic analysis.
Abstract: The purification of calcium and barium has been carried out by double ultra high vacuum “reactive distillation” of these metals in a molybdenum column. The distributions of all elemental impurities and molecular species in the starting materials and in various fractions of the distillate were determined with spark source mass spectrographic analysis. The residual gases before, during and after distillation were analyzed by a quadrupole mass spectrometer. The total contents of metallic impurities (carbon and silicon included) of the double distilled metals were, in calcium 124 at. ppm and in barium 69 at. ppm.
TL;DR: In this paper, several grams of 241 Am have been prepared by two independent methods: lanthanum reduction of the oxide and thermal dissociation of the intermetallic compound Pt 5 Am.
Abstract: In order to redetermine some physical and chemical properties of americium metal, several grams of 241 Am have been prepared by two independent methods: lanthanum reduction of the oxide and thermal dissociation of the intermetallic compound Pt 5 Am. After its separation from excess lanthanum or alloy constituent by evaporation, americium metal was further purified by sublimation at 1100 C and 10 −6 Torr. Irrespective of the method of preparation, the temperatures of evaporation or condensation and the material of the condenser, the americium samples displayed the same d.h.c.p. crystal structure. As determined by vacuum hot extraction, the oxygen, nitrogen and hydrogen contents are equal or smaller than 250, 50 and 20 ppm, respectively.
TL;DR: In this article, an investigation has been made of the mechanical properties of titanium and of Ti-05 wt% Si and Ti-1Ow% Si alloys in the temperature range 300-900k Dynamic strain ageing (DSA), characterised by serrated yielding, has been observed between 700 and 825k and has been studied by measurements of strain rate sensitivity and of stress relaxation.
Abstract: An investigation has been made of the mechanical properties of titanium and of Ti-05 wt% Si and Ti-1O wt% Si alloys in the temperature range 300–900K Dynamic strain ageing (DSA), characterised by serrated yielding, has been observed between 700 and 825K and has been studied by measurements of strain rate sensitivity and of stress relaxation The DSA is attributed to interstitial atoms, and is increased in magnitude by the presence of silicon, probably due to lattice distortions resulting from silicon-interstitial atom pairs; the temperature of dynamic strain ageing is reduced by increases in silicon or oxygen content The powerful solid solution strengthening role of silicon at elevated temperatures may arise from the intensification of the interstitial strain ageing effect by the silicon
TL;DR: Free energies for displacement reactions involving metals and their fluorides have been measured at various temperatures by the solid electrolyte galvanic cell technique as discussed by the authors, and the results are presented in the form of cell e.m.f. vs. temperature equations.
Abstract: Free energies for displacement reactions involving metals and their fluorides have been measured at various temperatures by the solid electrolyte galvanic cell technique. The results are presented in the form of cell e.m.f. vs . temperature equations. By combining these results with data from the literature, standard free energies of formation data for the fluorides studied have also been calculated and tabulated for use in conventional thermodynamic calculations.
TL;DR: The binary system ytterbium-nickel has been investigated by X-ray diffraction, differential thermoanalysis and metallography and the corresponding constitutional diagram has been derived.
Abstract: The binary system ytterbium-nickel has been investigated by X-ray diffraction, differential thermoanalysis and metallography and the corresponding constitutional diagram has been derived. At least five intermetallic compounds are present in this system: YbNi, YbNi2, YbNi3, YbNi5 and Yb2Ni17. Crystallographic data already known from preceding work have been confirmed. From lattice constant values of these compounds and from preliminary measurements of their magnetic properties it appears that ytterbium can form intermetallic compounds with nickel in the trivalent state but in the divalent state gives rise to an extended immiscibility gap in the solid as well as in the liquid phase.
TL;DR: In this article, the formation of vanadium with aluminum has been investigated under high pressures and temperatures (20-70 kbar, 1000-2000 °C) and it is suggested that it may be possible to synthesize cubic A 15 V 3 Al under very high pressures but that cubic A15 Nb 3 Si should not form at any pressure.
Abstract: The formation of the two compounds Nb 3 Si and V 3 Al has been investigated under high pressures and temperatures (20–70 kbar, 1000–2000 °C). In no case was it possible to synthesize a compound with the cubic A 15 structure, but in both cases a body-centered cubic structure, previously unknown, has been obtained. Other new compounds of vanadium with aluminum are also reported. The appearance of the A 15 structure is discussed and it is suggested that it may be possible to synthesize cubic A 15 V 3 Al under very high pressures but that cubic A 15 Nb 3 Si should not form at any pressure.