Solubility Of Sn Research Articles

Influence of Sn on the structural and thermoelectric properties of the type-I clathrates Ba8Cu5Si6Ge35-xSnx (0 ≤ x ≤ 0.6)

ABSTRACTOn the search for cost-competitive thermoelectric clathrates we have investigated the influence of Sn substitutions for Ge on the structural and thermoelectric properties of the type-I clathrate Ba8Cu5Si6Ge35. The solid solubility of Sn was found to be limited to 0.6 atoms per unit cell. A series of compounds with the nominal compositions Ba8Cu5Si6Ge35-xSnx (x = 0.2, 0.4, 0.6) was synthesized in a high-frequency furnace. The samples were annealed, and subsequently ball milled and hot pressed. The hot pressed samples were characterized by X-ray powder diffraction, energy-dispersive X-ray spectroscopy and transport property measurements. Our results show that the substitution of Ge by Sn introduces vacancies at the 6d site of the type-I clathrate structure and shifts the highest dimensionless thermoelectric figure of merit ZT from 570 °C for the Sn free sample to lower temperatures. The highest figure of merit ZT = 0.42 is reached at about 320 °C for the Sn-substituted sample Ba8Cu5Si6Ge35Sn0.6.

Surface segregation of tin by heat treatment of dilute aluminium–tin alloys

The changes in the microstructure and surface morphology, caused by heat treatment, of binary AlSn model alloys, containing 30–1000ppm tin were investigated with the purpose of understanding activation of aluminium by trace element tin in aqueous media. Specimens prepared by casting and cold-rolling in the laboratory were annealed for 1h at 300 or 600°C and quenched in water, and then characterised by various surface-analytical techniques. In the as-rolled condition, tin was in solid solution with aluminium. The microstructure and surface morphology in this condition were not different from those of pure aluminium. Significant segregation of liquid Sn occurred by annealing at 300°C to the metal surface, caused by the combined effect of limited solubility and high mobility of Sn in Al at this temperature. Segregated Sn caused oxidation of aluminium during water quenching following heat treatment. The resulting oxide formation increased with increasing Sn content of the alloy from localised cases to extensive coverage by a 1.3μm thick scale. Most of the Sn was homogenised in solid solution with Al by annealing at 600°C for all Sn concentrations. The alloy containing 1000ppm Sn still formed a thick oxide as a result of quenching in water after heat treatment, caused by enrichment of Sn at the metal–oxide interface by dealloying of Al.

Mechanically Driven Dissolution of Sn in Near-Equiatomic Bcc FeCo

Ternary alloys, (Fe50−x/2Co50−x/2)Snx(x ≤ 33 at.%), are prepared by mechanical alloying from powder mixtures of the three elements. As-milled alloys are studied by X-ray diffraction and 57Fe and 119Sn Mössbauer spectroscopy. The solubility of Sn in near-equiatomic bcc FeCo is increased from ~0.5 at. % at equilibrium to ~20 at.% in the used milling conditions. The average 119Sn hyperfine magnetic field at room temperature is larger, for any x, than the corresponding fields in mechanically alloyed Fe-Sn solid solutions.

The inorganic speciation of tin(II) in aqueous solution

This paper reports new voltammetric measurements on the interactions between tin(II) and the most important natural inorganic ligands, OH−, Cl−, F−, CO32-, SO42- and PO43-. For a better understanding of tin(II) speciation, an analysis is also given of prior data on the same systems from the literature. The formation constants were determined at t=25°C in different ionic media and at different ionic strengths, specifically the following: Sn(OH)q (0.1⩽I/molL−1⩽1.0 in NaNO3), SnClr and Sn(OH)Cl (0.1⩽I/molL−1⩽2.3 in Na(NO3, Cl)), Sn(SO4)r (0.1⩽I/molL−1⩽1.6 in Na(NO3, SO4)), SnHqCO3 and SnHqPO4 (0.15⩽I/molL−1⩽1.0 in NaNO3), where the subscripts r and q represent the stoichiometric coefficients. Concerning the SnFr species, reliable literature values were considered (0.15⩽I/molL−1⩽1.0 in NaClO4). Fifteen voltammetric measurements were performed in synthetic seawater; the total seawater binding ability was evaluated by a model in which synthetic seawater is expressed as a single salt, BA. The formation of species between tin(II) and the anion of the marine salt (A) was also proposed, and the corresponding stability constants at different salinities (5⩽S⩽50) were reported. In addition, studies on the solubility of Sn(OH)2(s) were carried out using voltammetry and light scattering measurements. The “extra-stability” of the mixed species with respect to the parent species was evaluated, in particular for Sn(OH)Cl and the corresponding species involving the anion of the marine salt (A). The dependence of the formation constants on ionic strength was analysed using extended Debye-Hückel and Specific ion Interaction Theory (SIT) type equations. Tin(II) speciation was also evaluated in different natural fluid conditions, where, in all cases, carbonate complexation was predominant, hampering the formation of hydrolytic species throughout the investigated pH range. Moreover, some formation enthalpy changes were calculated for the Sn(OH)+, Sn(OH)2(aq), Sn(OH)2(s), Sn(OH)3-, Sn2(OH)22+, Sn3(OH)42+, Sn(OH)Cl, SnCl+, SnCl2 and SnCl3- species on the basis of the available literature stability constant values at different temperatures and using the empirical relationships reported in the literature. The ΔH values at t=25°C were positive in all cases except for the Sn(OH)2(s) and Sn(OH)3- species, indicating an increase in the stability constant values with increasing temperature.This work represents an advance in the knowledge, understanding and modelling of the inorganic speciation of tin(II) in natural fluids, particularly for solutions containing chloride, fluoride, sulphate, carbonate and phosphate anions.

Phase Equilibria in the Ni-Sn-Zn System at 500°C

The isothermal section of the Ni-Sn-Zn ternary system at 500°C was investigated by means of x-ray diffraction (XRD), and scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS). A new ternary compound with a composition of Ni36Sn42Zn22 (in at.%) was discovered in the present study. The space group of this compound is P\( \overline{\textit{4}}\)3m with lattice parameter a = 0.88283(4) nm. Two ternary phases, i.e., τ1 and τ2, which are derived from α′-Ni3Sn2 and β-NiZn, respectively, were observed to be present at 500°C. The solubility of Sn in Ni2Zn11 was determined to be about 3.5 at.%, and that of Zn in Ni3Sn to be about 5 at.%.

The effect of the concentration and oxidation state of Sn on the structural and electricalproperties of indium tin oxide nanowires

High quality single-crystalline indium tin oxide (ITO) nanowires with controlled Sn contents ofup to 32.5 at.% were successfully synthesized via a thermal metal co-evaporation method,based on a vapor–liquid–solid growth mode, at a substrate temperature of as low as540 °C. The high solubility of Sn in the nanowires was explained with the existence ofSn2 + ions along withSn4 + ions: thecoexistence of Sn2 + and Sn4 + ions facilitated their high substitutional incorporation into theIn2O3 lattice by relaxing structural and electrical disturbances due tothe differences in ionic radii and electrical charges between Sn andIn3 + ions. It was revealed that, while the lattice parameter of the ITO nanowires had a minimumvalue at a Sn content of 6.3 at.%, the electrical resistivity had a minimum value of about10 − 3 Ω cm at a Sn content of 14 at.%. These structural and electrical behaviors wereexplained by variation in the relative and total amounts of the two species,Sn2 + andSn4 + .

Electrodeposition of rhenium–tin nanowires

Rhenium (Re) is a refractory metal which exhibits an extraordinary combination of properties. Thus, nanowires and other nanostructures of Re-alloys may possess unique properties resulting from both Re chemistry and the nanometer scale, and become attractive for a variety of applications, such as in catalysis, photovoltaic cells, and microelectronics. Rhenium–tin coatings, consisting of nanowires with a core/shell structure, were electrodeposited on copper substrates under galvanostatic or potentiostatic conditions. The effects of bath composition and operating conditions were investigated, and the chemistry and structure of the coatings were studied by a variety of analytical tools. A Re-content as high as 77at.% or a Faradaic efficiency as high as 46% were attained. Ranges of Sn-to-Re in the plating bath, applied current density and applied potential, within which the nanowires could be formed, were determined. A mechanism was suggested, according to which Sn nanowires were first grown on top of Sn micro-particles, and then the Sn nanowires reduced the perrhenate chemically, thus forming a core made of crystalline Sn-rich phase, and a shell made of amorphous Re-rich phase. The absence of mutual solubility of Re and Sn may be the driving force for this phase separation.

Dendritic growth and solute trapping in rapidly solidified Cu-based alloys

Rapid solidification of binary Cu-22%Sn peritectic alloys and Cu-5%Sn-5%Ni-5%Ag quaternary alloys was accomplished by glass fluxing, drop tube and melt spinning methods. The undercooled, by glass fluxing method, Cu-22%Sn peritectic alloy was composed of α(Cu) and δ(Cu41Sn11) phases. If rapidly solidified in a drop tube, the alloy phase constitution changed from α(Cu) and δ(Cu41Sn11) phases into a single supersaturated (Cu) phase with the reducing of droplet diameter, and the maximum solubility of Sn in (Cu) phase extended to 22%. The Cu-5%Sn-5%Ni-5%Ag quaternary alloy was composed of (Cu) and (Ag) phases under the containerless processing condition in a drop tube, and the solute microsegregation of (Cu) phase was obvious. When the Cu-5%Sn-5%Ni-5%Ag quaternary alloy was solidified by melt spinning method, microsegregation was suppressed and solute trapping occurred. The experimental results show that the microstructures of primary (Cu) phase in the two alloys transfer from coarse dendrites into equiaxed grains with the increase of cooling rate and undercooling, which is accompanied by the grain refinement effect.

UV light emitting transparent conducting tin-doped indium oxide (ITO) nanowires

Multifunctional single crystalline tin-doped indium oxide (ITO) nanowires withtuned Sn doping levels are synthesized via a vapor transport method. The Snconcentration in the nanowires can reach 6.4 at.% at a synthesis temperature of840 °C, significantly exceeding the Sn solubility in ITO bulks grown at comparable temperatures,which we attribute to the unique feature of the vapor–liquid–solid growth. As a promisingtransparent conducting oxide nanomaterial, layers of these ITO nanowires exhibit a sheetresistance as low as and measurements on individual nanowires give a resistivity of2.4 × 10 − 4 Ω cm with an electrondensity up to 2.6 × 1020 cm − 3, while the optical transmittance in the visible regime can reach ∼ 80%. Under the ultraviolet excitation the ITO nanowire samples emit blue light, which can beascribed to transitions related to defect levels. Furthermore, a room temperature ultravioletlight emission is observed in these ITO nanowires for the first time, and the exciton-relatedradiative process is identified by using temperature-dependent photoluminescencemeasurements.

Diffusion Phase Formation in the Cu-Sn Nanofilms System

Processes involved in the structure and phase formation in the thin film systems Sn(4 nm)/Cu(14 nm) and Сu(14 nm)/Sn(8 nm) in the temperature range 130-500 оС were studied using “in situ” electron imaging and Transmission Electron Microscopy methods (TEM). Solubility of Sn α – solid solution Cu-Sn has been determined from the changes in the lattice parameter. This work was performed in the framework of the Swedish Institute supported cooperative research project “Thin metal films – the interplay of structure diffusion and boundaries” (SI dnr 00699/2009).

Formation of spherical SnO 2 particles consisting of nanocrystals from aqueous solution of SnCl 4 containing citric acid via hydrothermal process

We prepared crystalline SnO 2 particles from aqueous solutions of SnCl 4 with and without citric acid via hydrothermal treatment. The crystallinity, the crystallite size and shape, and the morphology of the secondary particles depend on the concentration of citric acid, the pH value of the solvents and the hydrothermal treatment temperature. Spherical SnO 2 particles of 1–3 μm in diameter consisting of nanocrystallites below 10 nm in size were obtained via hydrothermal treatment at 150 °C from a solution with the citric acid/SnCl 4 mole ratio of 0.5 in acidic solvents of pH 3.0–5.5. The SnO 2 spheres were thought to be formed through the moderate nucleation rate provided by the relatively high solubility of Sn 4+ species and coordination by citric acid.

Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes

This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.

Thermodynamic modeling of the Mg–Sn–Zn ternary system

Mg-based alloys have been investigated widely due to the great potential for high performance structural applications. In the present work, the Mg–Sn binary system was re-optimized using the CALPHAD method through Thermo-calc ® software package on the basis of available experimental information. Combined with the previous assessments of the Mg–Zn and Sn–Zn binary systems, the thermodynamic modeling of the Mg–Sn–Zn ternary system was performed. The liquid phase is described by the associated solution model with an associate Mg 2Sn, while the solid solution phases, hcp(Mg), bct(Sn) and hcp(Zn), are modeled by the substitutional solution model. The intermetallic compound Mg 2Sn is treated as a stoichiometric compound and its Gibbs energy was assessed considering the experimental heat capacity and heat content. The solubility of Sn in the Mg–Zn intermetallic compounds, Mg 7Zn 3, MgZn, Mg 2Zn 3, MgZn 2 and Mg 2Zn 11, is not taken into account. Liquidus projection and many vertical sections of this ternary system were calculated. The calculated results are in good agreement with the reported experimental data.

High‐Purity FeSe1−x Superconductors Prepared by Solid‐State Synthesis and Liquid Phase Processing

FeSe1−x samples have been prepared by a solid‐state reaction in the Ar+3% H2 gas flow. The samples sintered at 410°C were of the tetragonal PbO structure (β‐phase), showing little trace of δ‐phase (hexagonal). However, the samples sintered at higher temperatures contained a fair amount of δ‐phase, which was unable to be eliminated completely by subsequent annealing at ≤450°C for a prolonged period. Both M–T and R–T measurements showed that sintered samples of β‐phase were superconducting with an onset Tc above 8.1 K. Thick films of FeSe1−x were grown on LaAlO3 substrates by liquid phase processing with SeSn as the flux. In contrast to the sintering, the films grown around 910°C from the Sn‐containing liquid had a pure β‐phase. Although the phase diagram showed some solid solubility of Sn in FeSe, energy‐dispersive X‐ray spectroscopy failed to find Sn trace in the crystallized films, which showed a steeper superconducting transition at lower Tc of 6.0 K. To clarify whether the possible Sn contamination caused the drop of Tc, FeSe1−x:5% Sn samples were sintered, which showed little change of Tc from the pure β‐FeSe1−x. The cause for the Tc reduction of thick films remains unclear.

Microstructure and age characterization of Cu–15Ni–8Sn alloy coatings by laser cladding

The present work has investigated the influence of direct aging treatment on the precipitation sequence and properties of the Cu–15Ni–8Sn alloy coatings prepared by laser cladding. The experimental results show that the tendency of Sn segregation in the conventional Cu–15Ni–8Sn solidification microstructure is effectively relieved. Before aging, there are only two phases in the coating: the α-Cu solid solution dendrites with 7 wt.% Sn solubility, and a small fraction of Sn-enriched δ-phase at the interdendrites in rapid solidified microstructure. After the coating was directly aged at 370 °C without traditional solution pretreatment, the α-Cu solid solution dendrites experience precipitations in the order of pure spinodal decomposition, DO 22-ordered structure and discontinue γ-DO 3. The microhardness of the coating treated by direct aging reached 390 HV 0.5, which was higher than that treated by conventional solution and aging process owing to the solidified fine grains and hardening effect of spinodal decomposition. In addition, the Sn-enriched δ-phase at the interdendrites also decomposes to laminar discontinuous precipitated γ-DO 3 phase after aging. Precipitation sequence and properties of the clad coatings change obviously during the direct aging treatment.

Effect of Sn addition on the microstructure and magnetic properties of FePt thin film

An attempt has been made in this study to incorporate an alloying element to lower the order-disorder transformation temperature of Fe–Pt alloy and the effect of Sn addition was investigated for this purpose. The coercivity of the FePtSn film is measured to be about 5000 Oe, whereas that of FePt film is several hundred Oe at the annealing temperature of 300 °C. Therefore, Sn addition is effective to promote the L10 ordering and reduce the ordering temperature of FePt alloy. Analysis of crystal structure by x-ray diffraction reveals that the lattice expansion of cubic FePt phase is induced by Sn addition in as-deposited film. After the annealing from 300 °C to 600 °C, L10 ordered phase is formed in FePtSn films and lattice constant of FePtSn film is approached to pure FePt with increasing annealing temperature up to 600 °C. Difference in solid solubility of Sn between disordered and ordered phase exists and thus excess Sn will diffuse out from ordered FePt L10 phase. Segregated Sn is found at the surface and interfacial region of the ordered FePtSn confirmed by depth profiling of Auger electron spectroscopy. The key role played by Sn addition in FePt alloy is therefore explained by reduction in activation energy for the L10 ordering-disordering transformation through high internal stress in disordered phase induced by supersaturated Sn atoms.

Subsolidus Phase Relationships in the ZnO–In2O3–SnO2 System

The subsolidus phase relationships in the ZnO–InO1.5–SnO2 system were investigated at 1275°C using X‐ray diffraction. Each of the end members of the ternary diagram is a transparent conducting oxide. There are two substantial solid solutions in the ternary phase space, the bixbyite solid solution In2−2xZnxSnxO3 (x=0–0.40), and the indium substituted zinc stannate spinel, Zn(2−x)Sn(1−x)In2xO4 (x=0–0.45). The bixbyite solid solution is an outstanding TCO, whereas the spinel is only moderately conducting. Along the ZnO–InO1.5 binary, there is a series of transparent conducting homologous compounds (ZnO)k·In2O3 (where k=3, 4, 5, 6, 7, 9, 11). Within ternary phase space, these homologous compounds were found to exhibit negligible Sn solubility, and were always found to be compatible with the spinel. Equilibrium was difficult to achieve in the phase space between the homologous series compounds and the spinel, owing to sluggish kinetics. A procedure involving mixtures of prereacted spinel and the Zn11In2O14 (k=11) compound was developed, which allowed for more rapid approach to thermodynamic equilibrium, thereby allowing for the establishment of phase relationships near the ZnO corner of the phase diagram.

Thermal behavior of the amorphous precursors of the ZrO 2–SnO 2 system

Thermal behavior of the amorphous precursors of the ZrO 2–SnO 2 system on the ZrO 2-rich side of the concentration range, prepared by co-precipitation from aqueous solutions of the corresponding salts, was monitored using differential thermal analysis, X-ray powder diffraction, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). The crystallization temperature of the amorphous precursors increased with an increase in the SnO 2 content, from 405 °C (0 mol% SnO 2) to 500 °C (40 mol% SnO 2). Maximum solubility of Sn 4+ ions in the ZrO 2 lattice (∼25 mol%) occurred in the metastable products obtained upon crystallization of the amorphous precursors. A precise determination of unit-cell parameters, using both Rietveld and Le Bail refinements of the powder diffraction patterns, shows that the incorporation of Sn 4+ ions causes an asymmetric distortion of the monoclinic ZrO 2 lattice. The results of phase analysis indicate that the incorporation of Sn 4+ ions has no influence on the stabilization of cubic ZrO 2 and negligible influence on the stabilization of tetragonal ZrO 2. Partial stabilization of tetragonal ZrO 2 in products having a tin content above its solid-solubility limit was attributed to the influence of ZrO 2–SnO 2 surface interactions. In addition to phases closely structurally related to cassiterite, monoclinic ZrO 2 and tetragonal ZrO 2, a small amount of metastable ZrSnO 4 phase appeared in the crystallization products of samples with 40 and 50 mol% of SnO 2 calcined at 1000 °C. Further temperature treatments caused a decrease in and disappearance of metastable phases. The results of the micro-structural analysis show that the sinterability of the crystallization products significantly decreases with an increase in the SnO 2 content.

The role of Sn and Ti additions in the microstructure of Nb–18Si base alloys

The effects of Sn and Ti on the microstructure and hardness of the as cast and heat treated Nb–18Si–5Sn (NV9) and Nb–24Ti–18Si–5Sn (NV6) alloys were studied. In both alloys the phases present in the as cast and heat treated microstructures were Nb ss, Nb 3Sn and Nb 5Si 3. In NV9, Sn suppressed the formation of Nb 3Si, partitioned in Nb ss stronger than in Nb 5Si 3 and did not affect significantly the solubility of Si in the Nb ss. In NV6, the solubility of Ti in (Nb,Ti) ss increased in the presence of Sn, the concentration of Ti in Nb 5Si 3 was sensitive to cooling rate and the solubility of Sn in Nb 5Si 3 decreased as the concentration of Ti increased. The Ti controlled the partitioning of Si between (Nb,Ti) ss and Nb 3Sn and was considered responsible for the macrosegregation of Si in the as cast ingot. The transformation of β to α Nb 5Si 3 was enhanced by the synergy of Sn and Ti. The addition of Ti did not destabilise the Nb 3Sn. Silicon increased the hardness of Nb 3Sn significantly, Sn did not affect the hardness of Nb 5Si 3 and Ti reduced the hardness of Nb 3Sn and Nb 5Si 3 significantly. The hardness of NV9 and NV6 decreased and increased, respectively, by heat treatment. The reduction of the hardness of NV6-AC compared to NV9-AC is attributed to the strong effect of Ti on the hardness of Nb 3Sn and Nb 5Si 3.

Isothermal section at 1400 °C of the Ti–Zr–Sn system

By the methods of X-ray diffraction, metallography and microprobe examinations the character of phase equilibria at 1400 °C is studied for the Ti–(Ti,Zr) 5Sn 3–Zr region of the Ti–Zr–Sn system. The isothermal section at 1400 °C is constructed. This is similar to the solidus surface and is characterized by two 3-phase regions: 〈βTi,Zr〉 + Ti 3Sn + (Ti,Zr) 5Sn 3 and Ti 3Sn + Ti 2Sn + (Ti,Zr) 5Sn 3. Solubility of Sn in 〈βTi,Zr〉 solid solution is between 10 and 15 at.% Sn. Solubility of zirconium in Ti 3Sn is about 12 at.%.