Showing papers on "Antimony published in 1986"
TL;DR: In this article, an intentionally doped gallium antimonide has been grown by molecular beam epitaxy on gallium arsenide and gallium anti-antimonide, and a strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material was obtained with the minimum antimony stable growth at a particular substrate temperature.
Abstract: Unintentionally doped gallium antimonide has been grown by molecular‐beam epitaxy on gallium arsenide and gallium antimonide. Substrate temperatures in the range 480 to 620 °C and antimony to gallium flux ratios from 0.65 : 1 to 6.5 : 1 have been investigated. The deposition conditions have been related to growth morphology and to the electrical and optical properties of the epitaxial films. A strong correlation has been found between the quality of the layers and the degree of excess antimony flux; the best material in terms of both optical and electrical properties was obtained with the minimum antimony stable growth at a particular substrate temperature. All the material exhibited residual p‐type behavior. The lowest hole concentration achieved was 7.8×1015 cm−3 with a corresponding room‐temperature mobility of 950 cm2/V s. The narrowest PL (photoluminescence) features observed were peaks associated with bound exciton transitions with half‐widths of 2–3 meV.
145 citations
Journal Article•
87 citations
TL;DR: In this paper, the role of the rutile structure of antimony-based catalysts in allylic oxidation reactions has been examined, showing that antimony oxides stabilize in matrices with rutiles.
Abstract: Several authors have correlated catalyst structure to catalytic behavior in selective oxidation reactions. Sleight [1] reviewed the importance of the scheelite structure for the allylic oxidation and ammonoxidation of olefins; Grasselli and co-workers [2–4] extensively examined the relationship between structure and catalytic activity of bismuth-molybdates, uranium-antirnonates, and bismuth-cerium molybdates. Bordes and Courtine [5] correlated the activity in mild oxidation of 1-butene to the properties of the structure of vanadium-phosphorus oxides. However, little attention has been given in the literature to the role of the rutile structure in allylic oxidation reactions even though the high activity and selectivity of antimony oxides stabilized in matrices with rutile structure (SnO2 and FeSbO4) in olefins oxidation and ammonoxidation have been known for several years. Furthermore, Tables 1 and 2 indicate that the kinetic and catalytic behavior of antimony-based catalysts in allylic oxidation...
82 citations
62 citations
TL;DR: Transparent Sb-doped SnO2 films were prepared at 600°C on glass substrates by thermal decomposition of tin 2-ethylhexanoate and antimony tributoxide as mentioned in this paper.
Abstract: Transparent Sb-doped SnO2 films were prepared at 600° C on glass substrates by thermal decomposition of tin 2-ethylhexanoate and antimony tributoxide. The films 100 to 300 nm thick, which are composed of fine particles, were very smooth. The films showed no preferred orientation. The minimum resistivity (2.1×10−2Ω cm) was attained at a concentration of 8 at% Sb on the substrate precoated with SiO2. The transmission of these films was about 80% over a wavelength range from 0.4 to 2.0 μm.
59 citations
TL;DR: New Eh-pH diagrams have been derived for Sb, As, Cd and Tl. These diagrams are useful in discussing the common association of several or all of these elements around epithermal Au deposits.
55 citations
TL;DR: The monocrystalline antimony electrodes have the best reproducibility and long-term stability but also respond to complexing ligands and to variations in the oxygen pressure and the redox-response of the electrodes and the effect of different oxygen pressures on the electrode potentials were studied.
54 citations
TL;DR: In this paper, the surface films formed were analyzed by energy dispersive spectroscopy in a scanning electron microscope, using a convenient method for analysing films on substrates, and the film thickness and chemical composition determined show the thermal conditions existing at the surface.
46 citations
TL;DR: In this article, the effects of nickel and cobalt and their interaction with antimony on the electrowinning of zinc from industrial acid sulphate electrolyte were studied using X-ray diffraction, scanning electron microscopy and cyclic voltammetry.
Abstract: The effects of nickel and cobalt and their interaction with antimony on the electrowinning of zinc from industrial acid sulphate electrolyte were studied using X-ray diffraction, scanning electron microscopy and cyclic voltammetry. Concentrations of cobalt as high as 20 mgl−1 had no effect on the zinc deposition current efficiency. The current efficiency decreased rapidly when the electrolyte contained >5 mgl−1 nickel. Neither cobalt or nickel had an effect on the morphology of the 1-h zinc deposits. Nickel and cobalt caused characteristic changes in the cyclic voltammograms for zinc deposition. As a result this technique might provide a rapid means for evaluating the electrolyte prior to zinc electrowinning. The combined presence of cobalt and antimony in the zinc electrolyte was more deleterious to zinc electrowinning than was the combined presence of nickel and antimony. The presence of 0.08 mgl−1 antimony in the electrolyte counteracted the effect of nickel both on the current efficiency for 1-h deposits and on the zinc deposition polarization curves.
43 citations
TL;DR: In this article, self-organization phenomena are observed during electrodeposition of silver-antimony alloys and the width of the black and white regions depends on the current density and the antimony content in the electrolyte.
Abstract: Self-organization phenomena are observed during electrodeposition of silver-antimony alloys. On increasing the current density, black regions (assumed to be an antimony-richer phase) appear on the electrode surface. Under certain conditions these black regions are shaped as spirals with different topological charges. The width of the black and white regions depends on the current density and the antimony content in the electrolyte. Quantitative characterization of the phase composition in the black regions is a problem which still remains to be solved.
40 citations
01 Jan 1986-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, an experimental investigation into the removal of impurities (bismuth, lead, arsenic, and antimony) from baths of molten copper (blister, anode and cathode type copper) under vacuum was carried out.
Abstract: An experimental investigation into the removal of impurities (bismuth, lead, arsenic, and antimony) from baths of molten copper (blister, anode and cathode type copper) under vacuum was carried out. A pilot scale vacuum induction melting facility was used for these tests. The effects of (1) vacuum levels of 8.0 to 40.0 Pascals, (2) melt temperatures of 1150 to 1350 °C, (3) melt surface area to volume ratios of 6 to 10 m−1, (4) a water cooled condenser placed within a distance of two centimeters above the melt surface, and finally, (5) different levels of dissolved oxygen and/or sulfur contained in the melt, were studied. Kinetic data were obtained for evaluating the potential of a full scale vacuum melting facility. A mathematical model was also developed for the proper interpretation of the experimental results and for making projections for lower pressure and higher temperature levels. The rate of removal of bismuth and lead increased as the chamber pressure was lowered and the melt temperature increased, while removal of arsenic and antimony was negligible. Neither the melt surface area to volume ratio nor the distance of the condenser to melt surface had any significant effects on the rate constants governing the rate of removal of impurities. The rate of elimination of bismuth and lead over the range of 1150 to 1350 °C and 40.0 to 8.0 Pa followed first order kinetics. Removal rates were largely controlled by mass transport in the gas phase.
TL;DR: In this paper, the detailed structural characterization of two β-Sb 2 O 4 compounds, Mo-doped and V-Doped, was reported, and the methods used to characterize them were described.
TL;DR: In this paper, a method for the determination of dissolved antimony (III) and antimony(V) species in natural waters is described, based on the rapid evolution of stibine from the sample solution by reduction with sodium tetrahydroborate(III), cryogenic pre-concentration and atomisation in an electrically heated quartz tube furnace mounted in the light path of an atomic absorption spectrometer.
Abstract: A method is described for the determination of dissolved antimony(III) and antimony(V) species in natural waters. The technique is based on the rapid evolution of stibine from the sample solution by reduction with sodium tetrahydroborate(III), cryogenic pre-concentration and atomisation in an electrically heated quartz tube furnace mounted in the light path of an atomic absorption spectrometer. Differentiation of antimony(III) and -(V) species is achieved by exploiting the pH dependence of the tetrahydroborate(III) reduction step. The procedure is applicable over a working range of 0–300 ng l–1 of antimony and permits a sample throughput of ca. 7 analyses per hour. Detection limits are ca. 10 ng l–1 for total antimony and ca. 1 ng l–1 for antimony(III). Potentially interfering species have been investigated but, at levels expected in natural waters, did not influence the analytical results obtained using the method.
TL;DR: In this article, the molar ratio of crown ether to the metal ions is probably 1 : 1, and the extracted species are probably extracted as chloro complexes, e.g., HFeCl4 and LiFeCL4.
Abstract: Chloroform solutions of dicyclohexyl-18-crown-6 (DC18C6), dibenzo-18-crown-6 (DB18C6) and 18-crown-6 (18C6) efficiently extracted iron(III), gold(III), gallium(III), thallium(III) and antimony(V) from solution in hydrochloric acid. Extraction with 15-crown-5 (15C5) and 12-crown-4 (12C4) was poor. Antimony(III) in the presence of titanium(III) chloride was efficiently extracted only with DC18C6. When tervalent iron, gold, gallium and thallium were extracted from acidic lithium chloride solution, even 15C5 and 12C4 gave good extractabilities. The molar ratio of crown ether to the metal ions, except antimony(III), in the extracted species is probably 1 : 1, and the metals are probably extracted as chloro complexes, e.g., HFeCl4 and LiFeCl4. Iron and gallium in aluminium-base alloys were determined after their separation by DC18C6 extraction.
TL;DR: In this article, a method for the continuous generation of the hydrides of arsenic, antimony, selenium and tellurium was described for the simultaneous determination of these elements by an atomic emission spectrometer with a 5kW nitrogen-argon inductively coupled plasma source.
Abstract: A method is described for the continuous generation of the hydrides of arsenic, antimony, selenium and tellurium and the simultaneous determination of these elements by an atomic emission spectrometer with a 5-kW nitrogen-argon inductively coupled plasma source. After digestion of the sample, the analytes are separated from the matrix by coprecipitation with iron(III) hydroxide at pH 2.40. A standard additions technique is used for quantification. This method is relatively free from interferences and is applied to the determination of arsenic, antimony, selenium and tellurium in silicate rocks containing gold and the platinum-group metals (noble metals), and also in sulphide ores rich in transition metals and lead.
IBM1
TL;DR: In this paper, it was shown that by the use of antimony one can reach sheet resistivity/ shallowness combinations that are superior to those achievable with arsenic, and the leakage of these junctions was found to be sufficiently low to allow VLSI applications.
Abstract: Extremely shallow, below ∼80 nm, n+ junctions fabricated with antimony have been analytically and electrically investigated. It is shown that by the use of antimony one can reach sheet resistivity/ shallowness combinations that are superior to those achievable with arsenic. The leakage of these junctions was found to be sufficiently low to allow VLSI applications. These investigations indicate that below a certain junction depth antimony should be the dopant of preference.
TL;DR: Antimony(III) is readily removed from aqueous systems by coprecipitation with ferric hydroxide and by adsorbing colloid flotation with ferrous hydroxides and sodium dodecyl sulfate as discussed by the authors.
Abstract: Antimony(III) is readily removed from aqueous systems by coprecipitation with ferric hydroxide and by adsorbing colloid flotation with ferric hydroxide and sodium dodecyl sulfate. Aluminum hydroxide is not effective in removing antimony. Precipitation with lime requires quite large quantities of lime in order to reduce residual Sb levels to desired levels. Precipitation of the sulfide in the presence of Fe(II) or Fe(III) may produce low residual concentrations, but runs the risk of exposure to highly toxic hydrogen sulfide.
TL;DR: In this paper, the surface segregation of antimony in a binary Sb alloy of ≈ 4wt% Sb content was studied by electron spectroscopic methods, and an imperfect c(2 × 2) structure was observed for a (100) oriented sample.
TL;DR: In this paper, gas phase metal clusters of antimony, bismuth, or antimony-bismuth alloys are prepared by laser vaporization and probed with UV laser photoionization in a time-of-flight mass spectrometer.
TL;DR: In this article, the effect of low incident antimony molecule fluxes during growth appeared to help reduce the density of deep levels below 1014 cm−3, which then allowed reproducible doping control in the low 1015 cm −3 range.
Abstract: Historically GaAlAs alloys grown by molecular‐beam epitaxy have high deep level concentrations (>1016 cm−3), low luminescent efficiency with broad peaks, and are difficult to dope controllably below mid 1016 cm−3. We report the effect that the low incident antimony molecule fluxes during growth appear to help reduce the density of deep levels below 1014 cm−3, which then allows reproducible doping control in the low 1015 cm−3 range. Exciton‐dominated photoluminescence with half widths ∼4.0 meV are now routinely achieved using this technique. Further evidence for the quality improvement of AlGaAs by heavy atom (Sb) doping comes from high 4 K two‐dimensional electron gas mobilities for low sheet electron densities, e.g., 1.3×106 cm2/V s for n=2×1011 cm−2. SIMS profiles of antimony content are presented and estimates of incorporated concentrations are given.
TL;DR: Results obtained for silver, antimony, bismuth and indium in some Canadian certified reference materials by these methods are compared with those obtained earlier by previously published methods.
TL;DR: In this paper, a fixed-size simplex was used to determine the optimum conditions for the simultaneous determination of arsenic, selenium, and antimony by hydride generation and inductively coupled plasma emission spectrometry.
Abstract: A fixed-size simplex has been used to determine the optimum conditions for the simultaneous determination of arsenic, selenium, and antimony by hydride generation and inductively coupled plasma emission spectrometry. The variables selected for the simplex were carrier gas flow rate, rf power, viewing height, and reagent conditions. The detection limit for selenium was comparable to the preoptimized case, but there were twofold and fourfold improvements in the detection limits for arsenic and antimony, respectively. Precision of the technique was assessed with the use of artificially prepared water samples.
TL;DR: In this paper, a metal antimony target is magnetron sputtered in a reactive vapor of trimethylindium (TMI) to deposit polycrystalline and homoepitaxial films of indium antimonide.
Abstract: Metalorganic magnetron sputtering has been used to deposit polycrystalline and homoepitaxial films of indium antimonide. In this technique a metal antimony target is magnetron sputtered in a reactive vapor of trimethylindium (TMI). Stoichiometric layers of indium antimonide could be deposited for all growth temperatures studied (20–370 °C). However, below 250 °C the films were either amorphous or composed of very small crystallites. Above 290 °C the layers were epitaxial as determined from the electron channeling patterns observed. For these layers the growth rate was controlled by the TMI flow with the excess antimony flux acting to stabilize the surface. The surface morphology was excellent with ‘‘mirrorlike’’ surfaces except at high TMI flows where indium surface droplets were formed.
TL;DR: In this article, a series of iron-chromium alloys were oxidized for 102 to 6×104 s in air and in the 295-500 K temperature range, and the apparent activation energies extracted from parabolic oxidation kinetics of the investigated metals were found to be in the 10−20 kcal/mole range.
Abstract: A series of iron-chromium alloys were oxidized for 102 to 6×104 s in air and in the 295–500 K temperature range. Room-temperature oxidation of iron, chromium, antimony, and copper were also conducted at extended times. Oxidation characteristics such as oxide thickness and composition of the oxide and of the underlying alloy were evaluated from measurements by electron spectroscopy for chemical analysis (ESCA). An initial selective oxidation of chromium with a concomitant chromium depletion in the alloy was found. This initial oxidation step is followed by growth of an outer, iron rich oxide which causes the former chromium depletion to vanish. Apparent activation energies extracted from parabolic oxidation kinetics (295–500 K) of the investigated metals were found to be in the 10–20 kcal/mole range.
TL;DR: The results of the spectroscopic studies indicate that the dithiocarbamate ligands are always bidentate, in both the 1:3 and 1:2 complexes as discussed by the authors.
01 Dec 1986-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the activities of arsenic were measured to determine activity coefficients of arsenic in the dilute solution region of molten copper, in Cu2S saturated copper, and in copper mattes equilibrated with copper at 1423 K by a mass spectrometric Knudsen effusion technique.
Abstract: In recent years, the concentration of the group Va elements such as arsenic, antimony, and bismuth has been increasing in copper concentrates. The elimination and recovery of these elements during the copper smelting process have presented serious problems. While the distribution of minor elements has been studied extensively, very little knowledge exists on the activities of these minor elements in copper mattes. Consequently, in this study the activities of arsenic were measured to determine activity coefficients of arsenic in the dilute solution region of molten copper, in Cu2S saturated copper, and in copper mattes equilibrated with copper at 1423 K by a mass spectrometric Knudsen effusion technique.
TL;DR: In this paper, a sensitive method for the determination of arsenic and antimony by hydride generation atomic absorption spectrometry, using a glass vial (internal volume, 8.6 ml) as the hydrated generator, is described.
Abstract: A sensitive method for the determination of arsenic and antimony by hydride generation atomic absorption spectrometry, using a glass vial (internal volume, 8.6 ml) as the hydride generator, is described. The optimum flow-rate of the carrier gas was 0.2 l min–1 and the hydrochloric acid concentration used was 0.25 M. The absolute sensitivities were 0.06 and 0.10 ng for arsenic and antimony, respectively. The relative standard deviations were around 2% for both elements. A masking solution consisting of thiourea and ascorbic acid proved to be effective for suppressing the effect of a number of interferents. The accuracy of the proposed method was checked by determining the contents of arsenic and antimony in two standard reference materials.