Function Of Tin Content Research Articles

Plasma-assisted chemical vapor synthesis of indium tin oxide (ITO) nanopowder and hydrogen-sensing property of ITO thin film

Transparent conducting indium tin oxide (ITO) nanoparticles were synthesized by plasma-assisted chemical vapor synthesis route using indium nitrate and tin nitrate as the precursors. The injected precursors were vaporized in the plasma flame followed by vapor-phase reaction and subsequent quenching of the vaporized precursors produced nanosized ITO. The amount of tin nitrate was varied to obtain 5, 10 and 15 atomic percent Sn designated as ITO1, ITO2 and ITO3, respectively. The grain size of the produced ITO powder increased with increasing plasma torch power. On the other hand, it decreased with increasing plasma gas flow rate. The electrical and optical properties of ITO films prepared by spin-coating a dispersion of synthesized nanoparticles on a glass substrate vary as a function of tin content. Hall effect measurements showed that the minimum resistivity of 6.65 × 10−4 Ωcm was obtained for ITO2 film. ITO1 and ITO2 film exhibited an average transmission of 85% indicating their suitability in optoelectronic applications. The ITO gas sensor was exposed to different concentrations of H2 gas and temperatures to evaluate its gas sensitivity. The optimum operating temperature and gas concentration of H2 showing the highest sensitivity was determined to be 350 °C and 400 ppm, respectively. The linear relation between sensitivity and concentration up to 400 ppm of H2 can benefit the actuator to detect the concentration of H2 and thus making it suitable for high-performance hydrogen gas sensing applications.

Synthesis of indium tin oxide (ITO) nanoparticles in supercritical methanol

Indium oxide (In2O3) and indium tin oxide (ITO; Sn-doped In2O3) nanoparticles are synthesized via a solvothermal method using surfactant-free supercritical methanol. X-ray diffraction analysis of the products indicates that crystalline indium oxide is formed within 2min at temperatures as low as 250°C. Transmission electron microscopy shows that the particles are single crystals and have a cubic shape with an edge length of about 20nm. The crystallite size of the particles calculated from X-ray diffraction is consistent with the particle size. The electrical resistivity and lattice parameters of the synthesized ITO nanoparticles vary as a function of tin content.

Synthesis of Sn-containing anatase (TiO2) by sol-gel method and their performance in catalytic water splitting under visible light as a function of tin content

Sol-gel route was employed to prepare a series of Sn-containing anatase with different molar (Ti/Sn) ratios ranging from 49 to 1. Samples were characterized by powder XRD, UV–vis, XPS, SEM, EDAX, low temperature N2 sorption technique and Raman Spectroscopy. Except anatase phase, no other crystalline phase was observed when Ti/Sn molar ratio was varied from 49 to 9 and for Sn free sample. However, further decrease in the ratio lead to the appearance of additional SnO2 phase whose peak intensities were increased with the increase in the tin content. Irrespective of tin content, all samples showed red-shift in UV–vis spectra. Moreover, samples showed Raman shift to higher vibration side from 143cm−1 to 147cm−1 indicating the doping of Sn2+ into TiO2. By virtue of low band gap, anatase crystallite size and an absence of XRD visible SnO2, ST (19) has shown maximum photocatalytic activity upon 1wt% Pt loading. It has exhibited the highest rate (0.1264mmole/g/h) for visible light induced hydrogen evolution by water splitting.

Simultaneous Synthesis and Sintering of Al2O3/TiN Composites using Capsule-free N2-HIPing from Al2O3 and Fine Ti mixed Powder Compacts

Synthesis of dense composite materials with the compositions of Al2O3/TiN=100/0∼90/10 vol% has been attempted directly from Al2O3/Ti mixed raw powder compacts using capsule-free N2 hot isostatic pressing (HIP). Fine Ti powders (0.3 μm in diameter) with a small amount of TiN0.3 phase were prepared by thermal decomposition of fine TiH2 powders at 400°C for 3.6×103 s in a vacuum, followed by thermal treatment in N2. Then, Al2O3/Ti mixed powder compacts with homogeneously dispersed Ti particles were fabricated and then HIP-sintered. During the first stage of HIPing [1350°C/6 MPa/3.6×103 s], solid/gas reaction between Ti and N2, in which both were contained in the powder compacts, was introduced to form TiN. Then, after the successive second stage of HIPing [1350°C/196 MPa/7.2×103 s], the most of sintered composites consisting of Al2O3 and TiN phases reached to a higher relative density than 98.5 % with closed pores, nevertheless a capsule-free HIPing. Dispersion of TiN particles (0.30∼0.35 μm) just formed suppressed the grain growth of Al2O3 during sintering. Mechanical properties, such as bending strength (σb), Vickers hardness (HV), and fracture toughness (KIC) have been evaluated as a function of TiN content.

Arsenite retention properties of water‐soluble metal–polymers

AbstractThe properties of water‐soluble metal–polymers to retain As(III) from aqueous solution are investigated. Poly(acrylic acid)s with different tin contents are prepared. Amounts of 3, 5, 10, and 20 wt % of tin are added to the polymer. The metal compositions are evaluated by thermogravimetry (TG‐DSC) and atomic absorption spectroscopy. Structural properties are analyzed by infrared and 1H nuclear magnetic resonance spectroscopy, and X‐ray diffraction. Additionally, specific surface area was measured using CO2 as adsorbate. Arsenic retention properties are studied using the liquid‐phase polymer‐based retention (LPR) technique. The polymers can bind arsenic species from an aqueous solution in the pH range 4–8. The studies show that the retention capacity is a function of tin content and polymer concentration. At pH 8, the following mol ratios poly(AA)‐Sn : As(III) are analyzed: 600 : 1, 400 : 1, 200 : 1, 100 : 1, and 20 : 1. The highest retention, 80%, is obtained with poly(AA)‐Sn at 10 and 20 wt % of tin at mole ratios 400 : 1, and at nearly to 20 : 1 or 40 : 1 Sn‐As(III). The highest retention is observed at pH 8 and 4. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Liquid-Phase Sintering and Properties of Si3N4–TiN Composites

Densification during liquid-phase sintering of Si3N4–TiN was studied in the presence of Y2O3. The content of TiN was varied from 0–50 mass%. During the densification Y-silicate was formed. The amount of silicate increased with both decreasing fraction of TiN and increasing isothermal heating time. Density, fracture toughness, and electrical resistivity were measured as a function of TiN content. It was found that the density and fracture toughness increased with increasing TiN content. The electrical resistivity drops drastically, from 1010 mΩ for sintered Si3N4 to 10−3 mΩ for sintered Si3N4–TiN composite containing 30 vol% TiN.

Sn-Substituted LaNi5 Alloys For Metal Hydride Electrodes

ABSTRACTOur research examines the efficacy of tin additions to LaNi5 in improving the hydrogen storage capacity of the material during charging/discharging. Alloys were prepared using high energy ball milling (mechanical alloying), a technique superior to arc casting for alloying elements with a wide disparity in melting points. Characterization by x-ray diffraction and Rietveld analysis shows that tin preferentially occupies the Ni(3g) sites in the LaNi5 structure, and the unit cell volume increases linearly with tin content to the maximum tin solubility of 7.33 atomic percent (LaNi4.56Sn0.44). We found that powders prepared by mechanical alloying and not exposed to air require no activation to induce hydrogen absorption. The hydrogen storage capacity in the gas and electrochemical phase was measured as a function of tin content. We found that with increasing tin, the plateau pressure decreases logarithmically, whereas the hydrogen storage capacity decreases linearly.

Effective diffusion coefficient involved in the high temperature viscoplastic behavior law of CuSn (15–20 at.% Sn)

Two independent sets of experiments were conducted to obtain a better understanding of the nature of the diffusion coefficients involved in high temperature viscoplastic deformation of binary alloys CuSn (15; 16.67; 18; 20.2 at.% Sn). On the one hand, apparent creep activation energies were measured by studying change in stationary creep rates as a function of temperature and tin concentration. On the other hand, an assessment of the results of 64Cu and 115Sn selfdiffusion in the different alloys was completed by measurements of tin 113 diffusion in Cu-15 at.% Sn; then it was possible to calculate, for each alloy, the values of the four diffusion coefficients generally involved in binary alloys creep processes and the values of the different diffusion activations energies. Comparing the variations of the calculated diffusion values in function of tin content with those of experimental creep measurements revealed that only one expression can account for the high temperature creep measurements performed in CuSn (15–20.2 at.% Sn). This expression, calculated by Fuentes-Samaniego et al. takes into account the atoms drag forces on gliding dislocations.

Electrical properties of ITO thin films deposited by activated reactive evaporation

The electrical properties of In 2O 3:Sn (ITO) thin films deposited by activated reactive evaporation from In-Sn alloys were investigated as a function of tin content in the alloy, substrate temperature and other deposition parameters. The influence of the plasma and of the ionic current on these properties is discussed. Films with electrical resistivity of 10 −3 Ω cm, mobility of 60 cm 2/V s and 90% transmittance were obtained.

Microstructural observations of sputtered silicon-tin-hydrogen alloys

Structural and compositional properties of hydrogenated silicon-tin alloys have been investigated as a function of tin content, sputtering pressure, and presence of hydrogen. Transmission electron microscopy, energy dispersive x-ray microanalysis, and scanning electron microscopy were used to detect compositional and structural inhomogeneities in these materials.

Geometric and electronic effects in the conversion of methylcyclopentane on Pt-Sn catalysts

With non-calcined bimetallic Pt—Sn/Al 2O 3 catalysts containing 1% Pt and 0.06 – 4% Sn, previous work has shown a complete reduction of tin for a content <1%. The properties of these catalysts were investigated for the conversions of methylcyclopentane (MCP), methylcyclopentene, hexane, cyclohexene and cyclohexane. A comparison of the product distribution clearly shows that the aromatisation of MCP follows a pure metallic route at temperatures lower than 673 K. Coke and sulphur deposition have effects similar to tin addition. The experimental evidence shows that for C-C bond rupture, the main role of tin is to dilute the platinum surface, as coke and sulphur do. Aromatisation goes through a maximum as a function of tin content. At high tin contents, the main reaction is dehydrogenation to methylcyclopentenes. Sulphur or coke does not affect aromatisation and dehydrogenation markedly. The special behaviour of tin is interpreted in terms of an electronic modification of platinum in the bimetallic catalyst.

Atom motions of copper dissolved in lead-tin alloys

The diffusion and electromigration of copper in lead-tin alloys containing up to 12 at. % Sn have been studied for sample temperatures between 100 and 317 /sup 0/C. The diffusion measurements were made by the standard sequential-sectioning technique, adapted to the 12.8-h half-life of the isotope /sup 64/Cu. The rapid decrease of copper diffusivity with increasing concentration of tin is interpreted as evidence for trapping with a binding energy of about 0.3 eV. Purity of the lead solvent proved to be very important in measuring the low-temperature diffusivity. Although our values of the copper diffusivity in ''pure'' lead are slightly higher than other reported values, our Arrhenius curves tend to fall at the lowest temperatures, showing the effect of trapping by minute amounts of unwanted impurities. The solubility of copper in the lead and in the lead-tin alloys was determined from those diffusion measurements where the surface concentration exceeded the solubility limit. One feature which is still under investigation is that, at low temperatures, the diffusivity as a function of tin content goes through a minimum and then increases perceptibly. The electromigration results were obtained by the steady-state method. The effective charge number for copper was determined to be aboutmore » unity, independent of tin concentration. In other words, the electromigration force on the mobile atoms is unchanged by the trapping phenomenon, although, of course, the time to reach equilibrium is prolonged.« less

Platinum-tin reforming catalysts: I. The oxidation state of tin and the interaction between platinum and tin

Two series of bimetallic Pt-Sn/alumina catalysts have been prepared by impregnation of samples of industrial Pt/alumina reforming catalysts with solutions of Sn(IV) chloride in acetone. The Pt content was constant at 0.3 wt% and the tin content was varied over the range 0.3 to 5.0 wt%. The reducibility of the catalysts was determined by temperature-programmed reduction, and by reduction in flowing hydrogen, followed by reoxidation in oxygen. The results show that the Pt catalyses the reduction of the tin. However, the average oxidation state of the tin after reduction is Sn(II), and no further reduction occurs even when Pt is present, or when reduction is continued for long times. The average oxidation state of the tin is independent of the concentration of tin on the catalyst over the whole range from 0.3 to 5.0wt%. The dispersion of the Pt has been determined, as a function of tin content, by measuring the amount of hydrogen chemisorbed. The chemisorption experiments show that the amount of hydrogen adsorbed by Pt is increased when tin is present, which indicates that tin increases the dispersion of the Pt. It is concluded that tin is stabilised in the Sn(II) state by interaction with the support and, consequently, that no proper Pt-Sn alloys are formed in these catalysts. The role of tin cannot be to divide up the surface into small ensembles of Pt atoms. It is proposed that the special properties of the catalysts are due to a change in the electronic properties of small Pt particles either by interaction with Sn(II) ions on the support surface, or by incorporation into the Pt of a few percent metallic tin as a solid solution.

Properties of CuSn bronze at 4.2 K

Mechanical properties of bronze at 4.2 K were determined as a function of tin content. The 0.02% offset yield strength varied from 76 MPa for pure copper to 241 MPa for an 8.2 w/o Sn bronze. The work-hardening modulus varied correspondingly from 1.9 GPa to 9.6 GPa. Electrical resistivity at 4.2 K was also measured as a function of tin content and found to vary from 1.27 × 10 −8 ohm-cm (pure copper) to 1.3 × 10 −5 ohm-cm (10.7 w/o Sn bronze).