Showing papers on "Antimony published in 1988"

Tin base lead-free solder composition containing bismuth, silver and antimony

Abstract: A lead-free solder composition of approximately 90% to 95% by weight tin, approximately 3% to 5% by weight antimony, approximately 1% to 4.5% by weight bismuth, and approximately 0.1% to 0.5% by weight silver.

Photofragmentation of antimony and bismuth cluster cations at 248 nm

Abstract: Antimony and bismuth cluster cations are produced by laser vaporization in a pulsed nozzle source and probed with mass spectroscopy and mass selected photofragmentation at 248 nm. Mass spectral abundances are interpreted to reflect cation stability patterns. Fragmentation products and branching ratios are consistent with the production of stable neutral and cation molecular fragments, suggesting a statistical dissociation mechanism.

Effects of certain impurities on zinc electrowinning in high-purity synthetic solutions

Abstract: The individual effects of lead, copper, nickel, cobalt and antimony on zinc electrowinning were evaluated by measurements in high-purity synthetic solutions, free from additives The coulombic efficiency (QE) of zinc electrodeposition was determined over 2h under mass transfer-controlled conditions at a temperature of 35°C and a current density of 400 A m−2 in a solution of 08 M ZnSO4+107 M H2SO4 Antimony had a very detrimental effect on QE causing decrease of ∼ 5 and 50% at 4 and 14 μg l−1, respectively Antimony also exerted a strong grain-refining effect and changed the deposit orientation from random to (112) to (004) with increasing concentration Lead had a small beneficial effect on QE at the electrode rotation rate employed (20 s−1) It also exerted a grain-refining effect and changed the deposit orientation from random to (102), (103), (104), to strong basal (004), (002) with increasing concentration Copper, nickel and cobalt had minor effects on QE, with reductions at 5 mg l−1 of 08, 03 and 03%, respectively The effects of copper on morphology and orientation were very concentration dependent, but with a general trend towards grain-refining and random orientation Nickel promoted coarse-grained deposits and changed the orientation from random to (114), (102) to (204), (102) with increasing concentration Cobalt had the least effect on the morphology of the deposit, although it gradually increased the basal plane orientation with increasing concentration

Palladium nitrate-magnesium nitrate modifier for graphite furnace atomic absorption spectrometry. Part 1. Determination of arsenic, antimony, selenium and thallium in airborne particulate matter

Abstract: When the palladium nitrate-magnesium nitrate modifier is used in the analysis of airborne particulate matter a common set of conditions for the determination of arsenic, antimony and selenium and with minor modifications thallium can be used. Under stabilised temperature platform furnace conditions, the interference-free determination of all four elements with calibration against matrix-free reference solutions is possible. Detection limits depend on the amount of sample collected. Absolute detection limits (3σ) of 75 ng for arsenic, 65 ng for antimony, 45 ng for selenium and 20 ng for thallium in total particulate mass were established. The precision of replicate analyses is typically better than 10% for all elements at the 10 µg g–1 level and better than 5% at higher analyte concentrations, except for arsenic, for which the precision was between 4 and 7%.

The doping of mercury cadmium telluride grown by molecular‐beam epitaxy

Abstract: The electrical properties of the mercury cadmium telluride semiconductor material grown by the molecular‐beam epitaxy are reviewed. The doping effects linked to the growth conditions, as well as the influence of indium or lithium incorporation are discussed. The results on doping by silicon, arsenic, and antimony are presented. It will be shown that all the impurities studied interact primarily with the metal site. It will confirm that the growth occurs under very rich tellurium conditions.

Effect of antimony additions on hardness and tensile properties of directionally solidified Al–Si eutectic alloy

Abstract: The effect of antimony additions on the hardness and tensile properties of Al–Si eutectic alloy has been examined during directional solidification. Antimony, provided that its concentration in the melt was maintained at ~0·1 wt-%, improved the mechanical properties of the eutectics by almost 20–25%, all effects being additive to those that can be gained through increasing the growth velocity of the samples. Mechanical properties were found to correlate directly with the spacing between the silicon particles of the eutectic phase of the solidification structure, a Hall–Petch type relationship existing between the yield strength and silicon particle spacing.MST/653

Silver alloys of exceptional and reversible hardness

Abstract: A unique hardenable silver alloy is provided which is solution annealed and preferably age-hardened to yield a silver alloy of exceptional and reversible hardness. The alloys utilize intermetallic systems comprising; silver, copper, combined with lithium alone or tin alone in varying percent amounts, or silver, copper, lithium and either tin or antimony, or silver, copper, lithium and either aluminum or indium or zinc, or silver, copper, antimony and either aluminum or indium or zinc, or silver, copper, lithium, tin and antimony, or silver, copper, lithium, tin and bismuth, or silver, copper, lithium, tin, bismuth and antimony.

Theoretical Mössbauer isomer shift of antimony chalcogenides.

Abstract: The electronic structure of five antimony chalcogenides (${\mathrm{SbI}}_{3}$, ${\mathrm{Sb}}_{2}$${\mathrm{Te}}_{3}$, SbTeI, ${\mathrm{TlSbS}}_{2}$, and ${\mathrm{Tl}}_{3}$${\mathrm{SbS}}_{3}$) is investigated. Tight-binding band-structure calculations and molecular models are combined with x-ray diffraction and photoemission spectroscopy to get a coherent picture of these materials. The same methods are used to discuss the chemical notion of the 5${s}^{2}$ antimony lone-pair stereochemical activity and to explain the observed trends in the M\"ossbauer isomer shift.

The Role of Oxide and Sulfide Additions in Solid Lubricant Compacts

Abstract: A study of antimony trioxide-molybdenum disulfide solid lubricating compacts found no evidence to support hypotheses that the tribologically beneficial role of antimony trioxide in those compacts results from sacrificial oxidation of antimony trioxide, direct retardation of molybdenum disulfide oxidation, or formation of eutectic of antimony and molybdenum oxides. Data do support a hypothesis that the role of antimony trioxide is to plastically deform at asperity flash temperatures permitting molybdenum disulfide crystallites attain and retain a preferred orientation to improve overall tribological condition. Studies of other and sulfides as bulk additions in lubricating compacts support the concept. Additional confirmation is provided by the finding that lower test temperatures are required to obtain the beneficial effect of antimony oxide additions to graphite as compared with additions to MoS2; evidently, higher flash temperatures are experienced by the graphite compact as shown by calculations. Excell...

Determination of arsenic, cadmium, lead, antimony, selenium and thallium in coal fly ash using the stabilised temperature platform furnace and Zeeman-effect background correction

Abstract: Four decomposition procedures for coal fly ash samples were investigated for the subsequent determination of arsenic, cadmium, antimony, selenium, lead and thallium. Decomposition with nitric acid under pressure in a PTFE bomb or microwave oven was adequate for the determination of As and Se but resulted in low values for all the other elements. Decomposition with nitric, hydrofluoric and perchloric acids in a PTFE bomb could be utilised for As, Se, Cd, Pb and Tl determinations whereas Sb was partly lost under these conditions. Decomposition with nitric, hydrofluoric and hydrochloric acids in a microwave oven was applicable for all the elements and gave results that were in good agreement with the certified values. The stabilised temperature platform furnace (STPF) technique with Zeeman-effect background correction was used for the determination of all the elements. After decomposition of the samples, calibration graphs were constructed using aqueous standards; use of standard additions was unnecessary for all the elements when using a Pd-Mg(NO3)2 mixed modifier. The atomic absorption spectrometry (AAS) results for As, Sb and Se were compared with those obtained by neutron activation analysis (NAA).

Conversion of methane to higher hydrocarbons

Abstract: Methane is converted into higher hydrocarbons by contact at a temperature in the range from 500° to 1000° C. with a contact solid comprising a manganese oxide incorporating at least one of the elements tin, titanium, tungsten, tautalum, silicon, germanium, lead, phosphorus, arsenic, antimony, boron, gallium, indium, a lanthanide or an actinide. The contact solid is preferably promoted by either an alkali or alkaline earth metal, for example sodium.

Thermodynamics for arsenic and antimony in copper matte converting. Computer simulation

Abstract: Thermodynamic data for arsenic and antimony and their sulfide and oxide gases have been critically reviewed and compiled. The entropy values for AsS(g), SbS(g), and BiS(g) have been recalculated based on a statistical thermodynamic method. The standard heat of formation and entropy of As2O3(g) have been newly assessed to be △H 298 0 = −81,500 cal/mole and S 298 0 = 81.5 cal/deg/mole. Copper matte converting has been mathematically described using the stepwise equilibrium simulation technique together with quadratic approximations of oxygen and magnetite solubilities in molten mattes. A differential equation for the volatilization of arsenic and antimony has been derived and solved for successive reaction microsteps, whereby the volatilization, slagging, and alloying of the minor elements in copper matte converting have been examined as functions of reaction time and other process variables. Only the first (slag-making) stage of converting is responsible for the elimination of arsenic and antimony by volatilization. Arsenic volatilizes mainly as AsS(g) and AsO(g), with As2(g) also contributing when initial mattes are unusually rich in arsenic (above 0.5 pct arsenic). Antimony volatilizes chiefly as SbS(g), and the contributions of other gases such as SbO(g) and Sb(g) always remain negligibly low. The results of the stepwise equilibrium simulation compare favorably with the industrial operating data.

Electrophotographic properties of SeTeSbHalogen alloy

Abstract: In order to reduce the residual potential of SeTe alloy, we clarified the effect of antimony and halogens on the electrophotographic properties of SeTe alloy. It was found that Se-(13 wt%)Te alloy doped with antimony (1 wt%) and chlorine (20 ppm) had sufficiently low residual potential and they had enough surface potential. It was also found that the addition of antimony improved the thermal stability of SeTe alloy.

Preparation of a catalytically active composition for the gas phase oxidation of propylene to acrolein and acrylic acid

Abstract: A catalytically active composition for the gas phase oxidation of propylene to acrolein and acrylic acid, of the general formula Mo.sub.12 Bi.sub.0.1-10 Fe.sub.0.8-12 [Co,Ni].sub.0.1-10 P.sub.0-2 A 0-10 B 0 .001-1 O x where A is arsenic, antimony, tin, thallium, tungsten, an alkaline earth metal, zinc and/or chromium, B is at least one of the metals sodium, potassium, rubidium, cesium and/or indium and X is the number determined by the atomic valences of the individual elements, is prepared by introducing all or some of the iron and molybdenum in the form of dried pulverulent iron molybdate gel into an aqueous solution or suspension of the other constituents and gelating the mixture by stirring and possibly heating, then comminuting, drying at elevated temperatures and finally calcining.

The contents and distributions of arsenic, antimony, and mercury in geothermal waters

Abstract: The contents and distributions of arsenic, antimony, and mercury in geothermal water samples taken from various geothermal areas in Japan were investigated. Since the existing forms of arsenic, antimony, and mercury in geothermal waters are complex and can change during sample storage, it is difficult to determine all of the chemical forms. In this study, therefore, the arsenic(III+V), antimony(III+V), and total mercury contents were determined. In geothermal water, there is a high positive correlation between the contents of arsenic and antimony. However, there is no correlation at all between the contents of mercury and arsenic, or between those of mercury and antimony. It can be assumed that mercury behaves differently from either arsenic or antimony in geothermal water.

Method for recycling electric arc furnace dust

Abstract: This invention relates to the metallurgy of iron and particularly to the separation and recovery of metals from electric arc furnace (EAF) dusts. While the invention discloses a process for the separation and recovery applicable to zinc, lead, cadmium and antimony contained in such EAF dusts, the invention is particularly applicable to the separation and recovery of zinc. This invention describes a method for reducing the zinc contained in an EAF dust, volatilizing the metallic zinc so produced from the mass of the dust, and reoxidizing the metallic zinc to zinc oxide along with the simultaneous regeneration of hydrogen which can be recycled to treat additional EAF dust.

An oblique section hydride generator for the simultaneous determination of arsenic, antimony and bismuth in geological samples by inductively coupled plasma-atomic emission spectrometry

Abstract: An oblique section hydride generator is developed for use in combination with inductively coupled plasmaatomic emission spectrometry. The generator offers less interferences from concomitant ions and transition metal ions when compared with the conventional hydride generators reported in literature. The emission signals and the detection limits of the analytes are also improved. The recommended hydride generator has been applied to the determination of arsenic at μg/g level and antimony and bismuth at subμg/g level in geological standard reference materials. A good agreement is achieved between the data obtained by the present study and the certified values.