Chapter

Synthesis of Powders and Coatings of Tin and Its Alloys with a Controlled Composition and Structure by Cementation from Solutions

Authors:
  • Research Institute of Research Institute for Physical Chemical Problems of the Belarusian State University
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Abstract

The experience of the research team in the field of cementation processes in which tin participates as a metal-cementator or tin is reduced by another metal from its compounds dissolved in solutions is generalized in the review. The processes of galvanic displacement were studied in the systems Zn/Sn(II), Zn/Ni(II), Zn/Ni/Sn(II), Sn/Bi(III), Sn/Cu(I), Cu/Sn(II), Sn/Ag(I), Sn/Au(I), Ni/Au/Sn(II). The conditions for tin coatings deposition on sublayers of copper, zinc, gold, as well as for obtaining Au-Sn, Sn-Ag, Sn-Cu, Sn-Bi, Sn-Zn bimetallic powders or Sn-Ni-Zn, Sn-Au-Ni ternary powders with the use of cementation processes has been developed. The effect of solutions composition, such as the nature the cementing metal and the metal to be reduced, the presence and composition of ligands, the components concentration, the solutions pH and temperature, on the rate of formation of tin containing products, their elemental and phase composition, as well as the morphology has been revealed. Methods to obtain tin based binary alloys of the eutectic composition, which are of special interest as low-melting lead-free solders, are proposed. The conditions for the formation of intermetallic compounds just during the cementation process have been found. The phase transformations in tin-containing products of cementation under low-temperature heat treatments were determined. The effect of side processes accompanying the reduction of metal ions from solutions, including reactions of hydrolysis and redox transformations in the volume of solutions, on the rate of formation, composition and microstructure of the products obtained is shown. Conditions are determined under which the cementation of a metal from a solution is accompanied by hydrogen evolution stimulated by the formation of a galvanic couple, and the effect of this process on the microstructure, the rate of deposition and thickness of the coatings produced is demonstrated. The obtained results are discussed with the use of known literature data.

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... Sn-Ni-Zn ternary powder alloy was obtained by two-stage synthesis providing metals ratio control [14]. At the first stage Ni(II) ions were reduced with zinc powder from aqueous solution containing 0.42 M NiCl 2 •6H 2 O at Ni 2+ : Zn molar ratio equal to 1 : 1, pH 1.2, 50 °C and stirring. ...
... The temperature of the end of this peak coincides with the reference data on the melting point of Sn-Zn eutectic. The shift of the peak to lower temperatures as compared with the melting point of the eutectic can be caused by ultrafine state of the resulting powders [14]. One more endothermic peak is observed at the temperature of 229 °C. ...
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This study focused on the preparation of dendrite-and needle-shaped alloy particles coated on the surface of copper powders by different molecular weights of polyvinylpyrrolidone (PVP)-namely, 3500, 8000, 10,000, 55,000 and 360,000-in displacement reaction and the thermal conductivity on composites' characterization. The structure, size, and morphology of the particles were investigated using scanning electron microscopy (SEM). The EDX demonstrated that the alloy particles simultaneously have different ratios of copper (Cu) and silver (Ag) elements for dendrite-shaped and needle-shaped alloy particles. The 15% of PVP with a molecular weight of 8000 g/mol formed the largest dendritic-shaped Ag-Cu alloy particle, with an average width of 3 +/- 1 mu m, in which 60% of Ag-Cu alloy particles included resin to enhance composites with the largest thermal conductivity at 0.5956W/(m K).
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Recent experimental results obtained by differential scanning calorimetry, Scanning Electron Microscopy and other methods were used to develop a thermodynamic description of the ternary system Ni-Sn-Zn. Four ternary non-stoichiometric compounds (T1-T4), mentioned in the literature, were described using three-sublattice models. Previously known optimizations of the binary subsystems were remodeled to comply with the new experimental data. The solubility of the respective ternary components, i.e., Zn in Ni-Sn phases and Sn in Ni-Zn phases, were taken into account and optimized ternary parameters were derived. Six isothermal sections were calculated using Thermo-Calc software.
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Complex three-dimensional hierarchical structures assembled from well-defined low-dimensional nanosized building blocks are an interesting class of nanomaterials with a rich variety of tunable physicochemical properties. Tin dioxide (SnO2) is an important n-type wide-bandgap semiconductor with wide applications in transparent conductive films, gas sensors, lithium-ion batteries, and solar cells. In this review, we outline synthetic strategies of hierarchical SnO2 nanostructures in terms of the dimension and the facet control of their constituting building blocks, creation of porous and hollow structures, as well as their modification by doping and loading with other elements. The design of hierarchical SnO2 nanostructures with an improved performance in lithium-ion batteries, sensitized solar cells, and gas-sensing applications is reviewed.
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The structure of Bi(III) clusters in aqueous concentrated acidic perchlorate solutions has been studied by means of X-ray absorption spectroscopy (XAS). The XAS data show that the polynuclear [Bi6O4(OH)4]6+ complex with a cage structure predominates at room temperature in acidic Bi-rich solutions. This complex breaks down to form mononuclear complexes with increasing temperature to 428 K. This behavior is consistent with theoretical predictions based on considerations of the electrostatic repulsion, which increases sharply as the dielectric constant of the solvent decreases with increasing temperature.
Article
Electrodeposition of tin from acidic chloride-gluconate baths was investigated. Equilibrium distribution of tin(II) species showed domination of Sn(II)-gluconate complexes, but for Sn2+ concentrations 50 mM or higher increased percentage of Sn(II)-chloride complexes was found. Cyclic voltammetry, anodic stripping analysis and potentiostatic measurements indicated that rate of the cathodic process is determined by the release of metal cations from gluconate complexes in diluted bath (5 mM), but for more concentrated solutions reduction of Sn(II) ions run under diffusion control. Studies of anodic response showed that it depends on the Sn(II)/Glu ratio in the bath and deposition potential due to development of different planes of metal crystal. Average effective diffusion coefficients of metal species were determined. Morphology and structure tin deposits were also presented. The final publication is available at linkhttp://www.sciencedirect.com/science/article/pii/S0169433212021058
Article
Voltammetry, electrochemical quartz crystal microgravimetry (EQCM) and electrochemical impedance spectroscopy (EIS) were applied to study kinetics of cathodic processes occurring in acidic Sn(II) gluconate solutions containing an excess of sulphate. Simulations based on the material balance equations showed a rather complicated composition of the solutions involving gluconate, sulphate and hydroxide complexes of Sn(II). Equilibrium potentials following from the Nernst equation satisfactorily coincide with experimental open-circuit potentials. According to EQCM data, Sn(II) reduction is the main process occurring at sufficiently low cathodic polarizations (ΔE). An onset of hydrogen evolution was observed at ΔE ≈ −0.3 V (pH 4). The rotating disc electrode (RDE) and linear potential sweep (LPS) voltammetric data were analyzed using equations based on the charge transfer and diffusive mass transport regularities. The observed considerable decrease in the rate of Sn(II) reduction with solution pH is embodied in the respective diminution of the effective Sn(II) diffusion coefficient. Its values obtained from the limiting (RDE) and peak (LPS) current densities vary from ∼6 × 10−6 to 6 × 10−7 cm2 s−1 at 2 < pH < 5. Nyquist plots (EIS data) contain two semicircles that become clearly pronounced on subtraction of the double layer impedance. It is assumed that the electroreduction of Sn(II) in gluconate solutions is accompanied by adsorption phenomena whose inhibitive character enhances with solution pH.
Article
In this study, we performed a systematic study of the replacement reaction between silver nanoplates and an aqueous HAuCl4 solution. The aqueous HAuCl4 solution was adjusted to various pH values before the reaction. Under the different pH conditions, the hydrolyzed Au complexes existing in the solution have different concentrations. As a result, the total standard potential of the solution decreased with increasing pH. Thus, the pH was used to investigate the morphological, structural, compositional, and spectral changes of the reaction on the nanoscale. The alloy and dealloying processes were monitored and different structures were obtained. This work has enabled us to prepare metal nanostructures with controllable shapes at room temperature and their optical properties could be readily tuned by adjusting the pH.
Article
To synthesize low-cost, highly conductive metal nanoparticles for inkjet printing materials, we synthesized Sn–Ag bimetallic nanoparticles using a polyol process with poly(vinyl pyrrolidone). Because a surface oxidation layer forms on Sn nanoparticles, various compositions of Sn–xAg [x = 0, 20, 40, 60, 80, 100 (wt%)] nanoparticles were synthesized and characterized for the purpose of removing the β-Sn phase. The results of XPS, TEM, and XRD analyses confirm that the formation of a bimetallic phase, such as Ag4Sn or Ag3Sn, hinders the β-Sn phase and, consequently, leads to the removal of the surface oxidation layer. To measure the sheet resistance of various compositions of Sn–Ag nanoparticles, we made the ink that contains Sn–Ag by dispersing 10 wt% of Sn–Ag nanoparticles in methanol. The sheet resistance is decreased by the conductive Sn–Ag phases, such as the fcc, Ag4Sn, and Ag3Sn phases, but sharply increased by the low-conductive Sn nanoparticles and the surface oxidation layer on the Sn nanoparticles. The sheet resistance results confirm that 80Ag20Sn and 60Ag40Sn bimetallic nanoparticles are suitable candidates for inkjet printing materials.
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A number of divalent metal halides with ethylene glycol as the ligands is reported. The general formula is M(EG)nX2, where M = Mn, Co, Ni, Cu, Mg, Ca, Sr; n = 1 – 4; and X = Cl, Br. The compounds are characterized by means of physical measurements and chemical analyses.Ligand field parameters are calculated for the Co, Ni and Cu compounds and the ligands is placed in the spectrochemical and nephelauxetic series.Infrared spectra indicated that both the symmetric and the asymmetric CO stretching vibrations are shifted to lower frequencies and the symmetric CCO bending vibration is shifted to higher frequency. The assignments of the vibrational spectrum of the ligands as appeared in the literature, are discussed.It is shown that ethylene glycol behaves as a normal oxygen donor, and that the ligand can serve as a bidentate chelating as well as a monodentate coordinating agent. Bidentate coordination is deduced for seven compounds and monodentate coordination for eight compounds. The gauche form with respect to the CC bond is present in the complexes.
Article
High-temperature oxidation of SnSe in the temperature interval 25 to 650‡ C has been studied by X-ray photoelectron spectroscopy, X-ray diffraction and thermal analysis techniques. Exposure to dry oxygen (760 torr pressure) at up to 200‡ C leads to the formation of SnO2 on the surface. The high-temperature bulk oxidation between 250 and 650‡ C goes through distinct steps of formation of intermediate tin oxoselenides, presumably SnOSe or SnSeO2 and its subsequent conversion to SnO2.
Article
In this work, the influence of tin on electrowinning of zinc from alkaline solution was observed. Tin changed the deposited zinc into compact form, made zinc hardly peel off from cathodes and should be separated from alkaline electrolyte before zinc electrowinning. Experiments for Sn removal from alkaline zinc solution by several chemical methods were tested. It was found that Sn can be cemented quantitatively from alkaline zinc solution by the addition of zinc powder at 95°C, 500 rpm with Zn/Sn molar ratio 6. The resulted Sn concentration in solution can be lower than 50 mg/L by zinc powder cementation. The experimental results were encouraging and practical for zinc recovery from Zn-Sn contained wastes by alkaline treatment.
Article
Electroless gold plating solution containing tetrachloroaurate and citrate ions together with urea is suggested that provides deposition of gold nonporous and adherent films ∼0.1 μm in thickness with a total surface area not less than 0.2 m2/l. The nature of gold reduction processes is studied and it is shown that in this solution gold is reduced by nickel (cementation process) and by citrate ions together with urea in a slight measure. The latter reduction proceeds on a substrate (gold plating on Ni-P and Ni-B sublayers) and in a solution bulk (formation of rather stable colloid solution). The quota of the cemented gold does not exceed 23–29 at.% compared to the whole gold quantity in films. It is shown that the accumulation of colloidal gold particles is accelerated by a metal of the substrate and coagulation is caused by nickel ions in a concentration ∼2.2×10−4 M. Gold plating can proceed in colloid solutions (containing ∼4×10−3 M gold in colloidal state) without a deterioration of the film quality.
Article
The development of chemical tin coatings by a replacement reaction Cu+Sn2+⇒Cu2++Sn from hydrochloric acid based and methanesulphonic acid based baths on the inner surface of a copper tube was studied by transmission electron microscopy and scanning electron microscopy in order to explore the factors influencing the uniformity of tin coatings. Despite the fact that tin coatings develop in different ways in studied baths, uniform coatings are equally plated from both these baths when the substrate surface is clean and smooth. However, differences in the surface-sensitivity, i.e. the dependence of coating uniformity on the substrate surface condition, of plating baths materialise when plated on irregular or improperly cleaned substrate. A hydrochloric acid based bath may yield non-uniform coatings on irregular or improperly cleaned substrate, since large-sized grains develop immediately after coating initiation. These large grains are suggested to orientate to follow the contours of impurity particles or surface irregularities introducing misalignment in grain columns and, thus, non-uniformity into coatings. In contrast, a methanesulphonic acid based bath is still able to produce uniform tin coatings on contaminated or rough surfaces, as the coating is proposed to accommodate to substrate surface irregularities by the build-up of a nanocrystalline zone at the early stages of tin coating deposition. Sulfur-containing elements in this methanesulphonic acid based plating bath play the central role in the nanocrystalline layer formation.