Mixture Of Gallium Research Articles

Applicability of Infrared Thermography for the Detection of Phase Transitions in Metal Alloys

This work aims at assessing the applicability of a screening-oriented device dedicated to the establishment of increasingly complex phase diagrams of phase change materials. A thermography-based method has recently been proven to allow the detection of phase transitions of organic materials for multiple samples at a time. The phase transition detection capability of the infrared thermography method is here evaluated for metal systems based on well-referenced materials commonly employed in DSC calibration (pure sample of Gallium and a mixture of Gallium and Indium). The detected transitions are compared to literature data and DSC measurements. All transitions documented in the literature could be retrieved by thermography, and liquidus transitions are validated with DSC measurements. The encouraging nature of the results is discussed, and avenues for improving the method are considered.

The Interaction Mechanism between Solid and Liquid Metals under Ultrasonic Action

At various structural-scale levels, the interaction between the aluminum alloy DT1 and a liquid eutectoid mixture of gallium and indium under the action of mechanical waves of the ultrasonic range is investigated. It is established that the deep penetration of the eutectoid mixture into the solid metal under ultrasonic action is due to the formation of channels along which the mixture moves. These channels are observed in both the axial and radial directions.

One step growth of GaN/SiO2 core/shell nanowire in vapor-liquid-solid route by chemical vapor deposition technique

GaN/SiO2 core/shell nanowires are grown by cobalt phthalocyanine catalyst assisted vapor-liquid-solid route, in which Si wafer coated with a mixture of gallium and indium is used as the source for Ga and Si and ammonia is used as the precursor for nitrogen and hydrogen. Gallium in the presence of indium and hydrogen, which results from the dissociation of ammonia, forms Si-Ga-In alloy at the growth temperature ∼910°C. This alloy acts as the source of Si, Ga and In. A detailed study using a variety of characterization tools reveals that these wires, which are several tens of micron long, has a diameter distribution of the core ranging from 20 to 50nm, while the thickness of the amorphous SiO2 shell layer is about 10nm. These wires grow along [101¯0] direction. It has also been observed that the average diameter of these wires decreases, while their density increases as the gallium proportion in the Ga-In mixture is increased.

Activation of metallic aluminum by tin and gallium chlorides in oxidation with water

We have studied the effect of gallium chloride and tin chloride solutions on the water oxidation of aluminum at SnCl2 concentrations of 0.68 and 6.32 wt %, GaCl3 concentrations of 0.56 and 2.67 wt %, and MCln: Al(M = Sn, Ga; n = 2, 3) molar ratios from 0.017 to 0.3. The results indicate that, when aluminum is oxidized in the presence of these salts, the reaction rate and hydrogen yield increase with reaction temperature and salt concentration and reach the highest levels when a mixture of gallium and tin chlorides is used. The reaction products are identified and the likely mechanism of the processes involved in the oxidation of aluminum is discussed.

Growth of Ga2O3 and GaP nanowires synthesized from mixed Ga/GaP powder as a precursor

High-purity gallium oxide (β-Ga2O3) and/or gallium phosphide (GaP) nanowires were synthesized on the nickel or the cobalt oxide catalyzed alumina substrate by a simple chemical vapor deposition method from a mixture of gallium (Ga) and gallium phosphide powder as a source materials. The source materials were directly vaporized in the range of 750–1000°C for 60min under argon ambient. The average diameter of nanowires in the optimum synthesis temperature was around 70nm and the length was up to several hundreds of micrometer. We confirmed that β-Ga2O3 nanowires were observed in all samples, while the GaP nanowires with β-Ga2O3 nanowires were only obtained in the sample synthesized on the nickel oxide catalyst at 950°C. The β-Ga2O3 and GaP nanowires have a single-crystalline monoclinic and zinc blend structure, respectively. And the both nanowires reveal the core–shell structure, which consists of the β-Ga2O3 or GaP core and the amorphous gallium oxide outer layer.

One-dimensional zigzag gallium nitride nanostructures

Two one-dimensional (1D) single-crystalline gallium nitride (GaN) nanostructures with periodic zigzag (type I) and diameter-modulated (type II) shapes have been synthesized by passing through ammonia over a mixture of gallium and gallium oxide (Ga2O3) powders held at elevated temperature. The process was catalyzed by the dispersion of thio-capped Au nanoparticles on the substrate onto which GaN nanostructures were condensed. The transformation between these two nanostructure morphologies was also observed. A possible growth model for the zigzag-shaped nanostructures is proposed, in which the formation of the zigzag nanostructures results from the construction of two different nanoscale unit cells. This work provides an avenue to a group of 1D nanostructures with a zigzag shape. The possibility to form 1D nanostructures yet to be discovered by changing the stacking direction of the (0001) plane will facilitate the fabrication of nanoscale functional devices as well as our understanding of the growth behavior of nanoscale crystallites.

Large-scale synthesis and photoluminescence of single-crystalline β-Ga 2O 3 nanobelts

Gallium oxide ( β-Ga 2O 3) nanobelts were synthesized on a large scale by a simple thermal evaporation method from a mixture of gallium (Ga) and silicon oxide (SiO 2) nanopowder at 850°C in argon atmosphere, which is 200–300°C less than that of thermal evaporation methods reported formerly. The nanobelts had a uniform single-crystal monoclinic structure with width ranging from 50 to 300 nm, thickness about 10–20 nm and lengths up to several tens or hundreds of micrometers. The growth of β-Ga 2O 3 nanobelts is controlled by vapor–solid crystal growth mechanism. Photoluminescence measurement shows that the nanobelts have one broad, strong blue emission and a UV emission.

Separation and Recovery of Gallium and Indium from Simulated Zinc Refinery Residue by Liquid−Liquid Extraction

The separation and recovery of gallium and indium from zinc refinery residue, using liquid−liquid extraction, has been investigated. The major components with the exception of zinc can be removed by extraction with tri-n-butyl phosphate at low aqueous acidity, and gallium and indium can be separated from the remaining major component, zinc, by extraction with bis(2-ethylhexyl)phosphoric acid (D2EHPA) using the correct conditions, at which effective separation may be feasible. Extraction equilibrium formulations for the ternary system containing gallium, indium, and zinc have been established up to high conversion conditions of the extractant to metal complexes, when D2EHPA is employed as the extractant and kerosene as the diluent. The scrubbing behavior for the process can also be expressed by the proposed extraction scheme. Simulation work based on the equilibrium studies shows that indium may be recovered effectively from the mixture of gallium and zinc with 98.9% overall fractional recovery and 100% purity when using 5.0 × 10-2 mol/L D2EHPA. Gallium may then be recovered from zinc with 87.9% overall fractional recovery and 99.1% purity using 1.0 × 10-2 mol/L D2EHPA.

Rare earth element and gallium diffusion in yttrium aluminum garnet

Diffusion of four rare-earth elements and gallium has been measured in yttrium aluminum garnet (YAG). Sources of diffusant were mixtures of alumina and rare-earth element oxides for REE diffusion, and mixtures of gallium and yttrium oxides for Ga diffusion. Diffusion profiles were measured with Rutherford backscattering spectrometry (RBS). For the rare-earth elements investigated, the following Arrhenius relations were obtained: DLa=6.87×10–1 exp (–582±21 kJ mol–1 /RT) m2s–1 DNd=1.63×10–1 exp (–567±15 kJ mol–1 /RT) m2s–1 DDy=2.70×100 exp (–603±35 kJ mol–1 /RT) m2s–1 DYb=1.50×10–2 exp (–540±26 kJ mol–1 /RT) m2s–1 Diffusion rates for the rare earths are quite similar, in contrast with trends noted for zircon. It is likely that these differences are a consequence of the relative ionic radii of the REE and the cations for which they substitute in the mineral lattice. For gallium, the following Arrhenius relation was determined: DGa=9.96×10–6 exp (–404±19 kJ mol–1 /RT) m2s–1 Gallium diffuses faster than the REE in YAG and has a smaller activation energy for diffusion. These data mirror relative trends in diffusion rates for YIG, in which trivalent cations occupying tetrahedral and octahedral sites (i.e., Al, Ga, Fe) diffuse faster than trivalent cations occupying dodecahedral sites (i.e., Y and the REE), and suggest that the rate-limiting process in the diffusion-controlled regime of solid-state creep of YAG is the diffusion of yttrium.

Trace element profile of semiconductor materials: Gallium and arsenic

An ion exchange methodology is described here for the quantitative separation and determination of trace elements from high purity gallium, arsenic and a mixture of gallium and arsenic. 0.5–2 g of the matrix is dissolved and subjected to an ion exchange separation process in acidic/alkaline (hydrochloric acid/ammonia with sodium hydroxide) medium to preconcentrate the analytes. The desorbed analytes were quantified using graphite furnace atomic absorption spectrometry/flame atomic absorption spectrometry/flame atomic emission spectrometry/neutron activation analysis/inductively coupled plasma atomic emission spectrometry. Most of the analytes were found to be present at extreme trace levels. The overall reproducibility of the procedure was 2–10% when compared with the blank values. Separation of the analytes were essentially complete as the recoveries were >95% which was confirmed by standard addition to the matrices and tracer studies.

XPS-Analysis of Ion-Beam-Induced Oxidation (IBO) of AlxGa1−xAs Substrates

ABSTRACTXPS analysis was used to characterise GaAs, Al0.4Ga0.6As and Al0.8Ga0.2As targets bombarded with an O2+ beam ranging from 1 keV to 5 keV. The bombardments were carried out at different angles of incidence from 0° to 60°. In all cases a strong preferential sputtering of arsenic gives rise to an As-depleted altered layer, formed by a mixture of gallium, arsenic and aluminium oxides with metallic gallium and arsenic. Aluminium and gallium are preferentially oxidized, a fact that correlates with the corresponding heat of formation of the oxides, whereas the arsenic oxidation requires a minimum incorporation of oxygen into the matrix. For all experimental conditions a considerably lower oxidation level has been observed in every case as compared to the IBO of silicon.

Thermodynamics of gallium(III) and indium(III) monoazide complexes in dimethyl sulphoxide solutions

The stability constants of gallium(III) and indium(III) monoazide complexes in DMSO solution at 25 °C have been determined spectrophotometrically using equimolar mixtures of gallium(III)–iron(III) or indium(III)-iron(III) perchlorates as constant ionic-strength media. Formation heats of both complexes have been studied calorimetrically. The thermodynamic functions for gallium and indium monoazide complex formation are, respectively: ΔG0Ga=–27.18 ± 0.23 kJ mol–1, ΔH0Ga=–6.68 ± 0.11 kJ mol–1, ΔS0Ga= 68.8 ± 1.1 J K–1 mol–1, ΔG0ln=–33.99 ± 0.11 kJ mol–1, ΔH0ln=–13.19 ± 0.17 kJ mol–1, ΔS0ln= 70.0 ± 0.9 J K–1 mol–1. The thermodynamic parameters are discussed in terms of hard and soft acceptor–donor interactions.

Manipulation of gallium restorative materials. 1. Control of wetting action of mixture by mulling with ethanol

The wetting action of gallium alloy is a handicap when handling the material. Ethanol mulling after mixing was assayed in an attempt to control the wetting action of such mixtures. A mixture of gallium and Ag-Sn-Cu spherical alloy particles was mulled with a small piece of an ethanol-soaked sponge for 10 seconds following mixing by an amalgamator. The effect of this mulling on the adherence of the mixture to the capsules, physical properties and microstructures was determined. Mulling with ethanol effectively controlled the wetting action of the mixture, and reduced adherence to the capsules without affecting physical properties. A decreased reaction phase around the alloy particles was observed in the microstructure of the ethanol-mulled specimen.

Spectrophotometric and calorimetric study of the gallium(III) monothiocyanate complex in dimethyl sulphoxide solutions

The stability constant of gallium(III) monothiocyanate in DMSO at 25 °C has been determined spectrophotometrically using equimolar mixtures of gallium(III) and iron(III) perchlorates as constant-ionic-strength media. Formation of the complex has been studied calorimetrically. The derived thermodynamic parameters are: ΔG°=–20.0 ± 0.7 kJ mol–1, ΔH°= 11.1 ± 0.2 kJ mol–1 and ΔS°= 104 ± 3 J K–1 mol–1.

Gaseous Phosphorus Compounds. IV. Thermodynamic Study of Gallium Monophosphide with a Mass Spectrometer and Dissociation Energy of Aluminum Diphosphide

Gaseous equilibria involving the GaP molecule have been studied by means of the Knudsen-effusion technique in combination with mass spectrometric analysis of the vapor phase. In order to obtain the desired phosphorus and gallium partial pressures of comparable magnitude, mixtures of gallium and either WP or Th3P4 which were evaporated from a graphite Knudsen cell were employed. From the experimentally determined partial pressures the equilibrium constants and the enthalpies of the reactions Ga(g)+0.5 P2(g)=GaP(g), Ga(g)+0.5 P4(g)=GaP(g)+0.5 P2(g), 0.5 Ga2(g)+0.5 P2(g)=GaP(g), and GaAg(g)+0.5 P2(g)=GaP(g)+0.5 Ag2(g) have been determined. These reaction enthalpies have been combined with appropriate literature data to yield the dissociation energy, D0° = 54.0 ± 3.0 kcal mol−1, the heat of sublimation, ΔHs,298° = 111.2 ± 5.0 kcal mol−1, and the heat of formation ΔHf,298° = 90.3 ± 4.1 kcal mol−1, of gaseous gallium monophosphide. The molecule AlP2 has been observed over the congruently vaporizing AlP(s). The enthalphy of the reaction AlP2(g)=Al(g)+P2(g) was obtained as ΔH0° = 33 ± 5 kcal mol−1. From this value the heat of atomization of AlP2, D0° = 149 ± 6 kcal mol−1, was calculated.