Formation Of Continuous Solid Solutions Research Articles

Synthesis and characterization of solid solutions in ABCO 4 system

Formation of continuous solid solutions with a tetragonal structure of K 2NiF 4-type was investigated by direct solid-state synthesis, carbonate precipitations, the freeze-drying method and the Czochralski crystal growth technique. In the systems of SrLaAlO 4–CaLaAlO 4, SrNdAlO 4–CaNdAlO 4, SrPrAlO 4–CaPrAlO 4, SrLaAlO 4–SrLaGaO 4 and SrLaAlO 4–SrLaFeO 4 solid solutions are formed in the whole concentration range (0.0⩽ x⩽1.0) and in the systems of SrLaAlO 4–SrLaMnO 4 and SrLaAlO 4–SrLaCrO 4 in the limited compositional interval of (0.0⩽ x⩽0.20) and (0.0⩽ x⩽0.25), respectively, with composition dependency of lattice constants following Vegard's law.

CdHgSe thin films: preparation, characterization and optoelectronic studies

We present a modified chemical bath deposition method used to grow Cd1−xHgxSe (0 < x < 1) pseudo-binary thin films with the objective to study growth kinetics, structural, optical and electrical changes. The method is based on the reaction of CdSO4, Hg(NO3)2 and Na2SeSO3 in an aqueous ammonical medium at a temperature of 5 °C. The reactant concentration, pH, deposition temperature and rate of agitation were found to influence significantly the quality and thickness of the films. The as-deposited thin films were characterized by x-ray diffraction (XRD), atomic absorption spectrophotometry, scanning electron microscopy, optical absorption and thermoelectrical techniques. The XRD study confirms the polycrystalline nature in a single cubic phase over the whole range of composition studied. The grain size is found to be similar for all compositions. An analysis of absorption spectra gave a direct type optical bandgap, the magnitude of which decreases monotonically as mercury content (x) in the film is increased while dark dc electrical conductivity at room temperature was found to increase nonlinearly from 10−6 to 102 Ω−1 cm−1. All the films showed n-type conductivity. The main features observed are the formation of continuous solid solutions in a single cubic phase, the absence of other crystallographic phases, the lack of solubility gap, and stability.

Interactions in the Co–Ni–Si system at 800°C

Abstract The isothermal cross-section through the ternary phase diagram Co–Ni–Si at 800°C was constructed. No ternary phases exist in the system at this temperature. The topology of the Co–Ni–Si isotherm is determined by the formation of continuous solid solutions between isomorphous Co2Si and Ni2Si intermetallics and cubic CoSi2 and NiSi2 phases and by rather extensive cobalt/nickel exchanges in other binary silicides. The CoSi intermetallic compound was found to be a dominant growing phase in the binary Co/Si as well as ternary Co–Ni/Si couples with the initial end-members containing up to 50 at.% of Ni. When the Co–Ni solid solution with 30–70 at.% of nickel was used, the formation of NiSi2 and NiSi (instead of CoSi2) intermetallics next to the Si-substrate was observed after interaction at 800°C.

Peculiarities of the interaction of the components in the systems of two rare earth metals and germanium

A review of the interaction of the components in the ternary systems R-R-Ge showed that they can be classified into three groups: (a) systems which are characterized by formation of the ternary compounds: (b) systems which are characterized by formation of continuous solid solutions and limited solid solutions between binary germanides; (c) systems in which both ternary compounds and continuous and limited solid solutions are formed.Results of the investigation of L10 spectra, magnetic susceptibility χ, thermopower α and specific resistivity ϱ of the RScGe compounds are presented. In SmSeGe compound intermediate valence is possible.

Isomorphism in the High-temperature Forms of Molecular Complexes between Aromatic Hydrocarbons and Various Electron Acceptors Arising from Molecular Motion

Abstract In addition to the six crystalline pyrene complexes reported earlier, the high-temperature forms of the following nineteen 1:1 molecular complexes have been found to be isomorphous to each other; the pyrene complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitrophenol, 4-nitrophthalic anhydride, pyromellitic dianhydride, 5-nitrobenzofuroxan, 4,6-dinitrobenzofuroxan, and benzotrifuroxan, the fluoranthene complexes with 2,4-dinitrophenol, 1,3,5-trinitrobenzene, 2,4,6-trinitrochlorobenzene, 2,4,6-trinitrophenol, 2,4,6-trinitrotoluene, 4-nitrophthalic anhydride, pyromellitic dianhydride, 4,6-dinitrobenzofuroxan, and benzotrifuroxan, and the phenanthrene complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitrophenol, and 4,6-dinitrobenzofuroxan. Furthermore, metastable isomorphous forms were obtained in the process of the solidification of the melt of the following three complexes: fluoranthene-5-nitrobenzofuroxan, phenanthrene-2,4,6-trinitrotoluene, and phenanthrene-4-nitrophthalic anhydride. Rather large entropies of the transitions to these unique high-temperature forms, up to 57 J mol−1 K−1, are often comparable with the entropies of melting, 46–67 J mol−1 Kr−1. The isomorphism in these twenty-eight complexes is demonstrated by essentially identical and very simple X-ray diffraction patterns and/or by the formation of continuous solid solutions between pairs of these forms. A trigonal lattice is proposed as the probable structure of these high-temperature forms. A broad-line 1H NMR study clearly showed that the unusual features of these isomorphous forms are mostly associated with the onset of a large degree of molecular motion at the transition temperatures.

Formation and Color of the Spinel Solid Solution in CoO-MgO-Cr&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;-TiO&lt;sub&gt;2&lt;/sub&gt;-SnO&lt;sub&gt;2&lt;/sub&gt; System

This study was concerned with the formation, color development and application for colored glazes of the spinel solid solution in CoO-MgO-Cr2O3-TiO2-SnO2 system.Specimens were prepared by calcining the oxide mixtures at 1400°C for 1hr. Concerning each specimens, the formation of spinel solid solution was investigated by X-ray diffraction, the color was discussed by means of spectral reflectance and the stability for various glazes was tested. The results were summarized as follows.1. A formation of continuous solid solution and an obedience to Vegard's law were confirmed by X-ray analysis.2. In MgO-Cr2O3-TiO2-SnO2 system, as the amount of Cr3+ increased, color ranged from yellow green through leaf to grayish leaf, and the absorption of Cr3+ shifted towards violet region.3. Colors which developed in CoO-MgO-Cr2O3-SnO2 system ranged from blue to bluish green, and the absorption of Cr3+ shifted towards violet region with increasing amount of Cr3+.4. As the amount of Cr3+ increased, colors obtained in CoO-MgO-Cr2O3-TiO2 system, ranged from bluish green through green to bluish green, and the absorption of Co2+ and Cr3+ shifted towards violet region.5. CoO-MgO-TiO2-SnO2 system revealed the colors ranging from blue to bluish green, and the absorption of Co2+ shifted towards red region as the amount of Ti4+ increased.6. Colors ranging from bluish green to green developed in CoO-MgO-Cr2O3-TiO2-SnO2 system.7. According to the results of the colored glaze tests, the specimens with the composition in Cr3+ rich region were appreciated to be stable as a glaze stain.

Structure of Basic Lead Chromates and Their Solid Solutions

The phase diagrams of the systems PbO. Pb(S-Cr)04, 2 PbOePb(S-Cr)04 and 4 PbOePb(S-Cr)O, were investigated by means of DTA and X-ray powder diffraction. ln these systems, the formation of continuous solid solutions were confirmed. The following crystal data of basic lead chromates were obtained on the bas is of basic lead sulfates.

Binding and semiconductor properties of AIIIBV compounds

A model for the interpretation of the characteristic properties of the A III B V compounds is proposed which takes into account the polarization of the valence electrons towards the B V ions. It is supposed that the polarization increases with increasing ionic part of the chemical bond and with increasing mean atomic weight. The influence of polarization on the lattice potential is investigated. It is shown that for A III B V compounds, especially InSb, a neutral binding is to be-expected, as proposed by J.C. S later and G.F. K oster ( Phys. Rev. 94, 1948 (1954)). The results are used to provide an explanation of the characteristic differences between the values of the energy-gap Δ E and the mobility ratio μ n μ p in the various A III B V compounds. Some pecularities concerning the mutual solubilities of A III B V compounds and the solubilities of elements of the Group IV of the Periodic System in the A III B V compounds are discussed. It is shown that for a continuous solid solution to be formed the polarizations must not differ too greatly. This rule allows the preferential formation of continuous solid solutions in the systems InAs-InP and GaAs-GaP to be explained.