Mixture Of Tin Research Articles

Mechanical alloying of a TiCTiN ceramic system

Reported here is a preliminary study of the mechanical alloying (MA) process of an all-ceramic-phases component, i.e., TiC + TiN. The respective ceramic powders were mixed in weight proportions of 50:50 and 70:30 and milled in a planetary ball mill at a ball-to-powder weight ratio of 20:1. High angle XRD peaks were used to calculate the lattice parameters before and after milling for different milling times. The lattice parameter measurements suggested that Ti(C,N) solid solution was formed during the MA process. Inter-particle necking was observed. The rate of the solid solution reaction seems to be independent of the compositional change in the TiCTiN mixture. Particle size refinement is achieved mostly during the first few hours of milling.

Properties of silicon-tin alloys prepared by pulsed laser deposition

Metastable thin-film alloys of tin and silicon have been grown on room temperature substrates by pulsed laser deposition. The composition of the targets, made by pressing pellets of a mixture of tin and silicon powders, was maintained in the deposited films. The granular films consisted of tin nano-crystallites surrounded by an amorphous matrix. Deposited films with tin concentration greater than 15% showed metallic behavior, optically as well as electrically, while films with tin contents less than 15% displayed optical bandgaps ranging from 100 to 300 meV. Charge transport in the semiconducting films can be modeled by a combination of conduction in extended states and hopping at the Fermi level.

TiN-TixSiy Codeposits A.P.C.V.D. Produced Using the TiCl4-N2-SiH2Cl2-H2 System

Mixtures of TiN x , TiSi 2 and Ti 5 Si 3 (N) were chemically vapour codeposited at atmospheric pressure using the TiCl 4 -N 2 -SiH 2 Cl 2 -H 2 system. Compact materials with very intimately dispersed phases and with controlled composition were obtained between 825-875°C and using flow rate ranges: 0.5 ≤ D N2 ≤ 2.5, and 0.05 ≤ D SiH2Cl2 ≤ 0.2 (in l/h). D TiCl4 and D H2 were kept constant at 0.183 and 30 (in l/h) respectively. According to the Ti-Si-N ternary phase diagram, TiN x with x = 0.95 ± 0.05, TiSi 2 and Ti 5 Si 3 (N), corresponding to some solubility of nitrogen into Ti 5 Si 3 , were in thermodynamical equilibrium. At 850°C, D TiC14 = 0.183 and D H2 = 30 (in l/h), the effect of N 2 and SiH 2 Cl 2 input concentrations were studied. At D SiH2Cl2 = 0.1 l/h, the deposition rate was found to increase linearly with the square root of the N 2 molar fraction up to 5.10 -2 , then to decline at higher concentration. TiN x was 20 mol% at DN 2 = 0.51/h, reached about 40 mol% at 1 l/h and remained almost constant while DN 2 increased to 2 l/h. At DN 2 = 2 l/h, about 70 mol% in TiNx was obtained with D SiH2Cl2 = 0.05 l/h. Then from D SiH2Cl2 ranging from 0,1 to 0.2 l/h, TiN x concentration remains almost equal to 35 mol%. A linear dependence in the SiH 2 Cl 2 concentration was observed for the growth rate. The relationship between the logarithmic plot of the growth rate versus the reciprocal of codeposition temperature (in Kelvin) was linear and an apparent activation energy of 105 kJ/mol was calculated. The effect of temperature on the TiN x preferred orientations was also evidenced.

Mossbauer spectroscopy investigations of the oxidation of alpha 2-Sn and beta -Sn types of structure at room temperature

The initial oxidation of two groups of tin structures with different chemical bindings, designated as alpha 2-Sn type and beta -Sn type, simultaneously grown by different electrochemical reductions is investigated by Mossbauer spectroscopy, and partly by X-ray photoelectron spectroscopy. It is shown that during the growth process the tin types become oxidized either to a mixture of tin(II) and tin(IV) oxides, or to tin(IV) oxides, but that the later oxidation in air at room temperature, monitored by periodic Mossbauer studies, is always to tin(IV) oxides. The kinetic results show that the mechanisms of oxidation of the two tin types are almost identical and that, if there is some difference, as suggested by parallel electron diffraction studies, it is beyond the sensitivity of the method. The oxidation of the tin types is a two-stage process, with a very large initial rate of oxidation, which decreases after aging for 1 or 2 months. Numerical equations describing parts of the oxidation curves are derived. The influence of impurities on the oxidation process is discussed.

Resistance to wear of nitriding on titanium alloy using the laser-irradiation technique

The introduction of nitrogen to titanium alloy (Ti6A14V) by laser irradiation under atmospheric pressure is characterized by : (i) the presence of a thin layer of TIN; (ii) the possible presence of an equally thin layer of Ti2N; and (iii) enrichment of the nitrogen-rich alpha phase film to depths of tenths of mm. The use of a laser leads preferentially to the substrate surface melting due to energy absorption, which is necessary for gas diffusion in the base metal. When nitrogen is present, nitrides are produced and are distributed throughout the melted area. The layer thus obtained, which is in fact a mixture of TiN, Ti2N and Ti dendrites, is generally thicker that obtained by conventional methods (ionic nitriding). The superficial hardness is around 900 HV100g but is considerably lower where the melted and non-melted areas meet. Turbine blades in nitrided titanium alloy were tested for resistance to wear in a series of trials aiming to determine an efficient method for protection against the effects of erosion by droplets of water. Extremely rigourous comparative tests with other techniques (laser-deposited metallic powders, sintered and soldered plates) showed that nitriding by laser irradiation displayed good resistance to wear in the incubation/initiation phase. In the weight-loss over time phase, it seems clearly that the melted and irradiated area should be around 1 mm thick.

Nitrogen-containing aluminium titanate

In the Ti-Al-O-N system a phase isostructural to aluminium titanate but with expanded unit cell dimensions was observed. It was stable between 1400 and 1700 °C and has unit cell dimensions of a=0.3719 nm, b=0.9703 nm and c=0.9869 nm with a composition of Ti1.004+Al0.543+Ti1.463+N0.283−O4.582−□0.14 Several samples were prepared by reaction sintering mixtures of TiN, Al2O3 and AlN powders at 1400 to 1470 °C for 4 h in a nitrogen atmosphere to maximize this phase. One specific advantage of the nitrogen-containing aluminium titanate over aluminium titanate is that the former is unchanged at 1150 °C in a nitrogen atmosphere whereas the latter decomposes. In the Al2O3-TiO2 oxide system Al2TiO5 solid solution extends to approximately Al0.75Ti2.25O5 at 1470 °C under the mildly reducing conditions of a graphite furnace. The unit cell volume increases linearly with the increasing replacement of Al3+ by Ti3+.

Synthesis of TiB2 powder from a mixture of TiN and amorphous boron

TiB2 powder was synthesized by solid state reaction using amorphous boron and TiN as a source of titanium. The TiB2 formation did not occur at all in a nitrogen atmosphere even at 1400° C. TiB2 formed above 1100° C in argon and hydrogen atmospheres. The only crystalline phase of TiB2 powder was favourably synthesized at 1400° C for 360 min in an argon atmosphere from a starting powder with a composition containing excess boron (B/Ti = 2.2). The synthesized powder was well dispersed and had a particle size of 0.5 to 2 µm. The powder activity was evaluated by sintering at 4 G Pa and 1300 to 1600° C for 15 min.

The tin/lead solid/liquid phase diagram: A computer-controlled experiment

83. Bits and pieces, 34. A computer interfaced experiment in which students plot the phase diagram for a mixture of tin and lead.

ChemInform Abstract: ASYMMETRIC REDUCTION OF PROCHIRAL KETO ESTERS WITH A CHIRAL REDUCING AGENT PREPARED FROM TIN(II) CHLORIDE, CHIRAL DIAMINE, AND DIISOBUTYLALUMINUM HYDRIDE

AbstractDie) Reduktion der prochiralen Ketoester (I) in Gegenwart des chiralen Amins (II) und Zinn(II)‐chlorid liefert die optisch aktiven Hydroxyester (III).

X-ray photoelectron spectroscopy studies of thin films of TiNx having different annealing histories

TiN thin films prepared by chemical vapor deposition (CVD) and annealed in different atmospheres were studied by means of x-ray photoelectron spectroscopy in conjunction with Ar ion bombardment. The films contained a high level of oxygen, and an intimate mixture of TiN and titanium oxide was postulated, based on the binding energy (BE) values of the Ti 2p core level photoelectrons. This was further supported by the independent effect of Ar ion bombardment on the two components and the constant nitrogen concentration throughout the film bulk. At this stage it seems unjustified to correlate differences in the Ti 2p spectra of the unsputtered samples with their annealing atmosphere histories, mainly because of the high oxygen content in all the films.

ASYMMETRIC REDUCTION OF PROCHIRAL KETO ESTERS WITH A CHIRAL REDUCING AGENT PREPARED FROM TIN(II) CHLORIDE, CHIRAL DIAMINE, AND DIISOBUTYLALUMINUM HYDRIDE

Abstract Asymmetric reduction of prochiral keto esters with a reagent, generated by treatment of a mixture of tin(II) chloride and a chiral diamine derived from (S)-proline with diisobutylaluminum hydride, afforded the corresponding optically active hydroxy esters.

Thermodynamic activity of magnesium in several highly-solvating liquid alloys

An emf technique is reported using porous alumina tubes to contain reference metals and alloys in a molten salt electrolyte. Data are reported for the activity of magnesium and its temperature derivative in several liquid metal solvents. These include lead (650 °C), tin (800 °C), bismuth (850 °C), antimony (850 °C), and mixtures of tin and antimony (800 °). In all cases, the solvents show strong negative deviations from ideal thermodynamic behavior, due to the effects of strong solvation caused by the formation of intermetallic compounds. The extent of this effect is Pb < Sn < Bi < Sb. The data reported are useful in evaluating solvents for the possible carbothermic reduction of magnesium oxide.

Synthesis of titanium nitrides by activated reactive evaporation

In this paper we deal with the experimental results on the synthesis of titanium nitrides by activated reactive evaporation. In this process, titanium is evaporated by a transverse electron beam source in the presence of nitrogen gas. The vapor species were activated by a low voltage plasma. The experimental variables studied were the evaporation rate, the partial pressure of nitrogen gas and the substrate temperature. The deposits were characterized by microhardness, X-ray diffraction analysis, adhesion measurement, scanning electron microscopy and transmission electron microscopy. It was observed that the hard deposits were essentially a mixture of TiN and Ti 2N phases. The deposition of hard coatings requires close control of the deposition parameters. A Knoop hardness of 2600–2800 HK (50 gf load) could be obtained under optimum conditions.

Experiments on Ge-Sn barrier Josephson junctions

Supercurrents have been observed through thick (∼500Å) barriers of co-evaporated Germanium - tin mixtures. The Critical current density is a strong function of the barrier composition and thickness. For 600Å thick barriers, a change in composition from 20% Sn to 50% Sn yields a factor of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> change in current density. Typically the critical current of the junctions decreases by a factor of 10 for every 80Å increase in barrier thickness. In general, the low current-density junctions show I-V characteristics which are well described by tunneling. High current-density junctions usually have characteristics which, depending on junction preparation, indicate either tunneling, or metal-to-metal conduction. By using smooth base-electrodes it is possible to make junctions with barriers as thin as 400Å that are effectively pinhole free and whose I-V characteristics show true tunneling. The relatively thick barriers of these junctions allow a substantial decrease in the junction capacitance per unit area compared to oxide barrier junctions. This lower capacitance allows the fabrication of junctions with non-hysteretic I-V characteristics having critical current densities as small as 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Using small-area, non-hysteretic junctions, we have made a high-sensitivity D. C. SQUID with an intrinsic energy resolution of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-31</sup> Joules/Hz.

Métallation Des Halogènures D'Aryle Par le Tributylstannyllithium Dans le HMPT

AbstractTributylstannyllithium was prepared in the absence of metallic lithium by cleavage of hexabutylditin with butyllithium in HMPA. It reacts with bromotoluenes in a completely regiospecific way. However parachloro and fluorotoluenes give mixtures of tin substituted compounds whose compositions strongly depend on the experimental conditions and on the nature of the halogen. All data are in agreement with a competition between anionic and radical mechanisms. Product analysis was realised by means of gas chromatography, NMR Spectroscopy (13C and 119Sn) and mass‐spectrometry.

The Activities and Activity Coefficients of Tin and Indium in Their Amalgams at High Temperature

Activities and activity coefficients of indium and tin in their amalgams were determined by means of potentiometric measurements in the temperature region 150°–200°C. The equilibrium potential of indium amalgam was far less noble than that of tin amalgam. In the case of tin amalgam, the activity coefficient decreased rapidly with temperature, but the difference between the normal amalgam potential and the standard electrode potential, , was kept practically constant. On the other hand, in the case of indium amalgam the activity coefficient was kept nearly constant, but the value of increased fairly. The temperature dependence of the activity coefficient was discussed in relation to the type of the amalgamation reaction. Indium amalgam was considered as a simple mixture of indium and mercury and tin amalgam was regarded as a complex such as , which was dissolved in a simple mixture of tin and mercury.

Nature of triethylphosphate as solvent — I

Tin(IV)chloride is miscible with triethylphosphate (TEP) and forms SnCl 4.OP (OC 2H 5) 3 and SnCl 4.2OP(OC 2H 5) 3. The solution behaviour of trans-bis(pyridine)tetrachlorotin(IV) in TEP suggests the heterolysis of the metal-chlorine bond. The kinetics of this reaction have been followed conductometrically at (25 ± 0·1)°, (30 ± 0·1)°, (35 ± 0·1)° and (40 ± 0·1)°. Addition of CH 3COCl to the complex in TEP leads to a higher rate of increase of conductance indicating nucleophilic substitution of pyridine by chloride ion. The rate constants for solvation, k s , and stepwise constants, k 1 and k 2 for substitution support a first order reaction and k 1 or k 2 ⪢ k s . The positive entropy of activation and magnitude of frequency factor also favour an S NI mechanism for the reaction. A decrease in PO frequency in the i.r. spectra of mixtures of tin(IV) chloride bis(pyridine) tetrachlorotin(IV) with TEP and the presence of the SnO frequency in far i.r. region indicate that coordination occurs through the oxygen atom of triethylphosphate.

Selective cis-isomerisation of but-1-ene by homogeneous catalysis with triphenylphosphinenickel complexes

The treatment of but-1-ene with a mixture of tin(II) chloride and triphenylphosphinenickel complexes prepared from (PPh3)2NiX2(X = Cl, Br, I), PPh3, and zinc leads to selective cis-isomerisation.

Backscattering of Gamma-Rays from Semi-Infinite Stratified Slabs of Alternating Tin and Aluminum Layers

The backscattering of γ-rays has been investigated from semi-infinite stratified slabs of alternating layers of tin and aluminum. The energy spectrum and the angular distribution of backscattered photons, as well as the number and energy albedos were obtained for 60Co and 137Cs point isotropic sources. They were compared with the data obtained with single layers of tin and aluminum. The stratified slabs of alternating layers were assumed in this study to be equivalent in property to a homogeneous mixture of tin and aluminum, and the effective atomic numbers were computed on this basis. The resulting values are found to agree with the effective atomic numbers corresponding to the albedo values obtained for the alternating layers.

The Isotope Effect in Superconductivity. II. Tin and Lead

The critical magnetic fields, $H$, of various isotopic mixtures of tin and of lead have been measured as a function of temperature, $T$.For tin, the critical temperature ${T}_{c}$ at zero field, is related to the average mass number, $M$, by the relation ${M}^{0.46}{T}_{c}=\mathrm{const}$. The critical magnetic fields, ${H}_{0}$, at absolute zero are proportional to the critical temperatures. The normalized values of critical field, $\frac{H}{{H}_{0}}$, are the same function of the variable $\frac{T}{{T}_{c}}$ for all the isotopes. An analytic expression for this function giving the best fit to the experimental data is given.The measurements on lead were made in the temperature range 1.6\ifmmode^\circ\else\textdegree\fi{}K to 4.2\ifmmode^\circ\else\textdegree\fi{}K. The data clearly indicate that the isotope effect is present in this superconductor.