Ga-Sn Alloy Research Articles

Self-Healing Liquid Metal and Si Composite as a High-Performance Anode for Lithium-Ion Batteries

Si is among the highest theoretical capacity anodes for lithium-ion batteries, but it suffers from huge volume expansion during lithiation. Here we report a new approach to alleviating the volume change-induced degradation of Si anodes by mixing Si with a room-temperature liquid metal (LM), namely, Ga–Sn alloy. The Ga–Sn alloy is fluid with self-healing ability, acting as the liquid buffer for the Si upon lithiation and delithiation and healing the cracks caused by the volume expansion and contraction. The resulting Si/LM composite exhibits a high capacity and excellent cyclicability. The composite anode delivers a reversible capacity of ∼670 mAh/g after 1000 cycles, with an outstanding rate capability.

Density, surface tension and viscosity of Ga-Sn alloys

In this work, the viscosity, density and surface tension of liquid Ga-Sn alloys were measured using the discharge crucible method (DC), and the effect of alloy composition on the temperature dependences of these properties are shown. The measurements were performed over a temperature range of 323–773 K. The viscosity and density of Ga-Sn alloys across a wide range of temperatures increase with increasing Sn content in the alloy, while surface tension decreases. The obtained experimental results were in very good agreement with the Prasad and Butler models for surface tension, and the Kozlov-Romanov-Petrov and Gasior models for viscosity.

Solidification of the eutectic Ga–Sn alloy

Cyclic thermal analysis is used to study the effect of overheating of the eutectic Ga–8.5 mol % Sn melt on the presolidification supercooling. It is found that, when the liquid eutectic is overheated above the eutectic temperature (T e = 293.5 K) and is subsequently cooled, the dependence of the presolidification supercooling on the overheating temperature exhibits monotonic ascending behavior. The maximum supercooling after heating of the melt to 339 K is 26 K. The kinetic and thermodynamic parameters of eutectic solidification are calculated using the thermal analysis curves measured during melting.

Experimental and numerical analysis of free surface deformation in an electrically driven flow

The present paper presents the experimental and numerical results of an electrically induced flow in a cylindrical container (188mm diameter) filled with a In–Ga–Sn alloy. The electric current is applied from copper electrodes of various diameters (4–8mm) and varied from 100 to 700A. The deformation of the free surface just under the electrode is reported in term of depth. At some critical current an arc develops around the electrode tip. To explore numerically what happens in such flows, calculations of the Magnetohydrodynamic (MHD) flow are performed. The numerical model is based on a potential formulation for the electromagnetic field. The evolution of the free surface flow is tracked with a VOF model. The electromagnetic parameters are fully coupled with the evolution of the free surface and the contact surface at the electrode. At low current density the interface is shifted downward by the pinch action of the Lorentz force. In the same time the rotational part of the Lorentz force drives the liquid metal flow in radial direction towards the electrode. The flow is accelerated towards the electrode and sinks in the form of a strong jet. At the high current density, the velocities are strong enough to induce further displacement of the interface by a Bernoulli mechanism. The combined action of the pinch and the rotational components of the Lorentz force on the interface displacement, scales as I2. The numerical and experimental results are in good agreements.

Investigation on hydrogen production using multicomponent aluminum alloys at mild conditions and its mechanism

A series of Al alloys with low melting point metals Ga, In, Sn as alloy elements were fabricated using mechanical alloying method. The phase compositions and morphologies of different Al alloys were characterized by XRD and SEM techniques. The reaction of the Al alloys with water for hydrogen evolving at mild conditions (at room temperature in neutral water) was studied. The results showed that there were no hydrogen yields for binary Al–Ga, Al–In, Al–Sn and the ternary Al–Ga–Sn alloys. The hydrogen yields were observed for Al–Ga–In and Al–In–Sn ternary alloys. The Al–In–Sn alloys showed an even faster hydrogen generation rate and higher yields than Al–Ga–In alloys. Based on the ternary Al–Ga–In and Al–In–Sn system, the hydrogen production property of quaternary Al–Ga–In–Sn was greatly improved. The hydrogen conversion efficiency of the optimized Al–3%Ga–3%In–5%Sn alloy was nearly 100% in tap water. The highest hydrogen generation rate reached 1560 mL/g min in distilled water or deionized water. It was suggested that both the embrittlement of Al by liquid Ga–In–Sn eutectic and the active points formed by intermetallic compounds In3Sn and InSn4 may be attributed to the high activity of Al–Ga–In–Sn alloys at room temperature.

Partial and integral enthalpies of mixing of Ag–Ga–Sn liquid alloys

A Calvet type calorimeter was used for measurement of partial and integral enthalpies of mixing of Ag–Ga–Sn alloys. The Ag–Ga binary alloys have been studied with 0 < x Ag < 0.79 composition and in the 803–1073 K temperature range. The mixing enthalpies at 803 K of Ga–Sn binary alloys have been determined for x Sn < 0.35. The Ag–Ga–Sn ternary liquid alloys have been investigated at 803 K along the following sections: x Ag/ x Ga = 1/3, x Ag/ x Ga = 0.36/0.64, x Ag/ x Ga = 1/1, x Ga/ x Sn = 1/3, x Ga/ x Sn = 1/1, x Ga/ x Sn = 0.65/0.35 and x Ga/ x Sn = 3/1. Experimental data were used to obtain the binary interaction parameters by using the Redlich–Kister polynomial for the Ag–Ga binary system, while the Redlich–Kister–Muggianu method was used to determine the ternary interaction parameters for the Ag–Ga–Sn system. The experimental values and the fitted curves were compared with those predicted from the Muggianu and Toop methods.

The dependence of the phase transition temperature of Ga–Zn eutectic alloy on its morphology

The effect of the crystallization conditions and the properties of the constituent components on the type of structures formed and the phase-transition temperature of Ga–Zn eutectic alloy is investigated. The structure of the Ga–Zn alloy is compared with the corresponding structures of the Ga–In and Ga–Sn alloys.

Preparation and characterization of p-type transparent conducting tin-gallium oxide films

p-Type transparent conducting tin-gallium oxide (TGO) films were successfully fabricated on quartz substrates by DC magnetron sputtering of GaSn alloy films followed by thermal oxidation. XRD characterization indicated that the TGO films maintain rutile structure of the tin oxide (SnO 2). UV–vis transmittance spectra indicated that the films have a transmittance higher than 85% in the visible region, with an optical band-gap around 3.8 eV. Hall effect measurement showed that electrical properties of the TGO films were dependent on oxidation temperature. Oxidation at too high or low temperature was unfavorable for p-type conduction. It is found that the optimum oxidation temperature for highest hole concentration (8.84 × 10 18 cm −3) was in the range of 600–650 °C.

Transition from alloying layer growth to island growth of Sn on a Ga-covered Si [formula omitted] surface

Atomic depth distribution and growth modes of Sn on an Si(1 1 1)-√3×√3-Ga(1 ML) surface at room temperature were studied after each monolayer deposition of Sn by using reflection high-energy electron diffraction (RHEED) and characteristic X-ray spectroscopy measurements as functions of the glancing angle θ g of the incident electron beam. Intermixing between Sn and Ga occurred after deposition of one monolayer (ML) of Sn, resulting in the formation of a flat film of Ga–Sn alloy. Above a critical Sn coverage of about 1 ML, the growth mode changed significantly. That is, the alloying between Sn and Ga was suppressed, and additional Sn grew into islands on the Sn–Ga alloy.

Phase transitions under high pressure inbinary Sn alloys (with In, Hg and Ga)

Crystal structures of binary alloys of Sn with In, Hg and Ga werestudied under pressure with diamond-anvil cells andenergy-dispersive diffraction of synchrotron radiation. The ambient-pressure simple hexagonal (sh)phase in In-Sn alloys becomes unstable under pressure above 13 GPaand decomposes into the mixture of two phases: the body-centredtetragonal (bct) phase and hexagonal close-packed (hcp)phase with compositions ~15 and ~25 at.% In,respectively. The hcp/bct phase boundary shifts towardsSn with increasing pressure. A similar behaviour was found for thesh phase in Hg-Sn alloys, where the hcp phase occurs athigher pressure. Another bct phase with an axial ratiosimilar to that in In occurs under pressure in the Hg-Sn alloysystem at the composition ~50/50.A sh phase was also found in the Ga-Sn alloy systemnear 80 at.% Sn at pressures above 11 GPa after heating to150 °C, showing a similarity to the ambient-pressuresh phases in In-Sn and Hg-Sn alloys.Structural sequences of phases in binary alloys are discussedwith respect to the valence electron concentration of thealloys, taking into account the results of the present andprevious structural high-pressure studies on Sn-based andrelated alloys.

Measurement of activity of gallium in liquid Ga–Sb–Sn alloys by emf method with zirconia as solid electrolyte

The emf of galvanic cells with zirconia solid electrolytes was measured to determine the activity of gallium in liquid Ga–Sb–Sn alloys in the 1050–1150 K temperature range along three lines of constant antimony-to-tin mole ratio. A mixture of Ga and Ga 2O 3 was used as a reference electrode. The activity curves of Ga show negative to positive deviations from the ideal behavior with increasing Sn concentrations in the lower concentration range of Ga; whereas in the concentration range X Ga≥0.6, the activity of Ga in the ternary alloys shows positive deviations from the ideal behavior. Isoactivity curves at 1073 K, in the ternary Ga–Sb–Sn alloys, were derived by combining the activity data for Ga–Sb and Ga–Sn alloys. The shape of the curves is simple in the Ga-poor region, but shows a wavy form with increasing Ga concentration. Isovalue curves in the excess free energies of mixing in the ternary alloys are derived by the Darken method. The results are in agreement with values derived by using the Chou method on the Sb-poor side, but the agreement is not good in the Sb-rich region.

Thermodynamic Activity in Liquid Ga&amp;ndash;Sn Alloys Studied by EMF Method

The E.M.F. of a galvanic cell with the zirconia solid electrolyte was measured to determine the activities of gallium at 1000-1200 K in the entire composition range of liquid Ga-Sn alloys, and some thermodynamic functions were derived from the results. The cell used was as follows: ( - )W | Ga, Ga 2 O 3 | ZrO 2 | ZrY 2 O 3 ) | Ga-Sn(1), Ga 2 O 3 | W (+). The activities of gallium in liquid Ga-Sn alloys at 1000 and 1200 K showed moderately positive deviations from Raoult's law in the whole composition range. The results were used to obtain the tin activity, the activity coefficient of gallium at infinitely dilute solution of tin, and the concentration fluctuation in long wavelength limit in the liquid alloys.

Atomic depth distribution and growth modes of Ga on Si(111)-2√3 × 2√3-Sn and √3 × √3-Ag

We analyzed depth distribution of composition and growth modes during Ga deposition on Si(111)-2√3 × 2√3-Sn and √3 × √3-Ag structures at room temperature. Applying RHEED-TRAXS (total reflection angle X-ray spectroscopy), the dependence of the X-ray (GaK, SnL, AgL, and SiK) emission on the glancing angle of the electron beam was measured. When 1 ML of Ga was deposited on the 2√3 × 2√3-Sn structure, the mixing of Ga and Sn atoms was clearly observed, and a quasi-√3 × √3-(Sn,Ga) structure was formed. After further Ga deposition, a liquid-like film of GaSn alloy was formed. When 1 ML of Ga was deposited on the √3 × √3-Ag surface, the structure was destroyed and a Ga layer was formed on the Si(111) surface, and Ag atoms which dissociated from the √3 × √3-Ag structure formed particles on the underlying Ga layer. For further deposition, a liquid-like Ga film grew, and Ag particles were buried in the Ga film without being destroyed. This alloying and separation of metals in atomic scale is discussed referring to the bulk phase diagrams of binary alloys.

接着性レジンの貴金属合金床への応用 Ｇａ‐Ｓｎ合金（Ａｄｌｌｏｙ）による被着金属表面改質法とＳｎ電析法の接着性の比較

A new simple modification method for adherend metals surface by using liquid Ga-Sn alloy (Adlloy) was investigated to applicate for the precious metal alloy denture. Surface of silver based alloy containing 12 wt% gold was modified by Adlloy and applied 4-META resin. The adhesive ability was studied by percolation tests and shearing bond strength, and compared with the results of tin electroplating method.The surface modification by Adlloy showed lower percolation ratio and higher shearing bond strength than tin electroplation method, suggesting that the method is effective for application to precious metal denture and would prevent percolation of salivary and food debris at the finishing line of denture.

Surface segregation in liquid GaSn alloys by AES

The surface segregation of Sn in liquid GaSn alloys has been studied by Auger electron spectroscopy as a function of bulk concentration at 350° C. The Sn was found to be strongly adsorbed at the surface. The surface concentrations of Sn and Ga were calculated from the Auger measurements using inelastic mean free paths and backscattering factors estimated in recent theoretical work. The values found for the surface concentrations are essentially in agreement with those deduced from surface tension measurements using Gibbs adsorption theory. This result supports a monolayer adsorption distribution in the GaSn system.

Surface segregation in liquid Ga-Sn alloys by AES

Surface segregation in liquid Ga-Sn alloys by AES

Temperature dependence of the sound velocity and ultrasonic attenuation in liquid BiGa and BiSn alloys

The temperature dependence of the sound velocity and ultrasonic attenuation in several liquid BiGa and BiSn alloys was determined by means of an ultrasonic pulse technique. The sound velocity is shown to be linear with temperature and parabolic with concentration in BiSn alloys, and in BiGa alloys in the miscibility region. This behavior indicates a correlation between the behavior of the electrical resistivity and of the sound velocity. A rapid gravitational separation was observed at 262°C for the critical composition in the Bi-43.77wt.% Ga alloy. Ultrasonic attenuation measurements permitted the accurate determination of the position of the interface (meniscus) between the separated liquid phases. The rate of motion of the meniscus as a function of temperature and composition was measured. The ultrasonic technique is shown to be useful for the accurate determination of phase diagram boundaries in systems with a liquid miscibility gap.

Summary Abstract: Surface segregation in liquid Ga–Sn alloys by AES

Summary Abstract: Surface segregation in liquid Ga–Sn alloys by AES

Untersuchung der thermodynamischen Eigenschaften flüssiger gallium-zinn- und gallium-wismut-Legierungen

For the determination of the thermodynamic characteristics of liquid Ga-Sn and Ga-Bi alloys the integral enthalpies of mixing were measured directly with a high-temperature calorimeter and the other excess functions calculated from melting equilibria using the measured values. The enthalpies of mixing are positive in both systems. The maximum values are ΔH max = 234 cal/g-atom and ΔH max = 504 cal/g-atom for the systems Ga-Sn and Ga-Bi, respectively. The excess entropies of liquid Ga-Sn alloys are positive ( ΔS ex max = +0.25 cal/g-atom °K), while in the intermediate concentration region of the system Ga-Bi negative ΔS ex values were found ( ΔS ex max = −0.2 cal/g-atom °K). A discussion of the factors which determine the thermodynamic behavior of an alloy leads to the assumption that the enthalpies of mixing in both systems are essentially dependent on an atomic misfit in the melt as the result of differences in atomic volumes.