Showing papers on "Copper published in 1973"
TL;DR: The diamond has the highest known thermal conductivity at 300k K at room temperature as discussed by the authors, and is the only non-metallic crystal with thermal conductivities of > 1 W/cmK at 300K.
1,523 citations
TL;DR: In this article, a method for fractionating soil copper was developed and applied to 24 soils representing a range of British soil types, and it was suggested that the concentration of copper in the soil solution is controlled by equilibria involving specifically adsorbed copper and that the bulk of the available soil copper reserves reside in the organically bound fraction.
Abstract: Summary
A method for fractionating soil copper was developed and applied to 24 soils representing a range of British soil types.
The scheme distinguishes five fractions:
(a)
soil solution and exchangeable copper;
(b)
copper weakly bound to specific sites;
(c)
organically bound copper;
(d)
copper occluded by oxide material; and
(e)
residual copper mainly in clay lattice structures.
Correlation and regression analyses confirmed the general validity of the scheme and indicated an association between free manganese oxides and copper which considerably influences the distribution of copper between the main soil constituents. It is suggested that the concentration of copper in the soil solution is controlled by equilibria involving specifically adsorbed copper and that the bulk of the‘available’soil copper reserves reside in the organically bound fraction.
519 citations
Esso1
TL;DR: In this paper, it was shown that ruthenium or osmium concentration in the catalysts was held constant at 1 wt% while the atomic ratio of copper-to-RUThenium ratio was varied from 0 to 1.
447 citations
TL;DR: A method based on that used by McAuliffe et al. (1948) for phosphorus was developed for determining isotopically exchangeable copper in soils using the radioisotope 64Cu as discussed by the authors.
Abstract: Summary
A method based on that used by McAuliffe et al. (1948) for phosphorus was developed for determining isotopically exchangeable copper in soils using the radioisotope 64Cu. The authors are confident that, with a few exceptions, isotopic equilibrium in soil/solution systems is attained rapidly enough to overcome possible difficulties resulting from the short half-life of this isotope. For the twenty-four soils examined, amounts of isotopically exchangeable copper were found to be between 0.19 and 12-24 μg g-I and represented between 2 and 21 per cent of the total soil copper.
A correlation test and an experiment involving fractionation of labelled soils both demonstrated that the bulk of the isotopically exchangeable copper was located in the organic-bound fraction. Not all copper specifically adsorbed by organic matter was readily exchangeable with 64Cu : for one sample of organic material examined only 20 per cent of the adsorbed copper was isotopically exchangeable after 24 hours equilibration. The corresponding figures for clay materials and oxide material were found to be between 75 and 60 per cent.
280 citations
TL;DR: In this article, the chemical shift between zinc electron binding energies in Zn and ZnO is very small, whereas the zinc Auger electron signals are separated by 4.3 eV.
269 citations
TL;DR: The surface structures and interior dislocation structures of fatigued copper and copper-5 at. % aluminium crystals have been studied using replicas and scanning and transmission electron microscopy techniques as discussed by the authors.
Abstract: The surface structures and interior dislocation structures of fatigued copper and copper-5 at. % aluminium crystals have been studied using replicas and scanning and transmission electron microscopy techniques. A very regular structure of walls of dislocations has been found; these walls consist of primary edge dipoles held together by a mesh of secondary dislocations. It is suggested that the wall structure is the ‘ideal structure’ to which other structures tend as the fatigue process progresses, and that this regular structure is found in the persistent slip bands.
251 citations
01 Oct 1973
TL;DR: The size and number density of precipitates formed during the early stage of precipitation of copper from Fe-1.4 at 500°C was determined with the field-ion microscope (FIM) as discussed by the authors.
Abstract: The size and number density of precipitates formed during the early stage of precipitation of copper from Fe-1.4 at. pct Cu at 500°C was determined with the field-ion microscope (FIM). While particles of less than 50 × 10−8 cm remain invisible in the electron microscope (ETM) they are clearly resolved with the FIM; particles as small as 8 × 10−8 cm in diameter could be detected. The growth rate of the particles can be accounted for by normal bulk diffusion. At its peak strength, the alloy contains approximately 1018 particles per cu cm with an average diameter of 24 × 10−8 cm. The alloy reaches its peak strength well before precipitation is complete.
248 citations
01 Oct 1973
TL;DR: In this paper, chemical analyses of individual precipitates found during the initial stages of precipitation of copper from Fe-1.4 at 500°C were made with the FIM-atom probe.
Abstract: Chemical analyses of individual precipitates found during the initial stages of precipitation of copper from Fe-1.4 at. pct Cu at 500°C were made with the FIM-atom probe. Precipitates as small as 8 × l0−8cm in diam were analyzed. The results indicate that the precipitate nuclei contain much less copper than the equilibrium e phase and that most of the particle-matrix boundaries are less than 10−7 cm wide. The average copper content of the precipitates increases with aging time until well after the alloy reaches its peak strength. Thermodynamic calculations show that it is reasonable to expect the precipitate compositions that were experimentally observed.
204 citations
194 citations
TL;DR: In this article, the thermal expansion of vitreous silica is shown to be particularly sensitive to thermal history values given for the linear coefficient α were determined relative to copper, and existing reference data for copper are discussed.
Abstract: Between 30 and 290 K the thermal expansion of vitreous silica is shown to be particularly sensitive to thermal history Values given for the linear coefficient α were determined relative to copper, and existing reference data for copper are discussed α for silicon has also been measured relative to copper from 55 K to room temperature Values of α at 283 K are reported for a number of samples of copper, and for Ag, Au, Al, Pt, Pd, MgO, NaCl and CaF2
183 citations
TL;DR: In this paper, electrical conductivity measurements have been made on copper sulfide crystals of compositions ranging from Cu1.8S to Cu2.0S in the temperature region between 20°C and 220°C.
Abstract: Electrical conductivity measurements have been made on copper sulfide crystals of compositions ranging from Cu1.8S to Cu2.0S and indium-doped Cu1.8S in the temperature region between 20°C and 220°C. Conductivity of Cu2-xS varied from 0.07 ohm-1cm-1 to 2400 ohm-1cm-1 as the deviation from stoichiometry increased from x=0 to x=0.2. It was found that Cu1.8S (digenite) and Cu1.96S (djurleite) undergo phase transitions at 90°C and at 93°C respectively. The transition temperature of Cu2S (chalcocite) increased from 98°C to 108°C as conductivity decreased from 52 ohm-1cm-1 to 0.07 ohm-1cm-1. An analysis of mixed conduction at β phase of low conductivity copper sulfide has shown that ionic conductivity is independent of the composition or the number of impurity cations in this material, and exhibits a temperature dependence with activation energy of 0.24 eV. Finally it is emphasized, after the discussion of the relation between electrical properties and crystal structure of copper sulfides, that the composition and crystalline phase are well characterized by the electrical conductivity in these materials.
01 Jan 1973
TL;DR: In this paper, the specific Cu+CO interaction was revealed by a strong infrared absorption band at 2160 cm− and a heat of adsorption of 14.7 kcal/mole.
TL;DR: In this article, the rate dependence of β hydroxybenzophenone oxime and aliphatic hydroxy-oxime oxime was investigated using an AKUFVE.
TL;DR: A survey, comparison, and critical analysis of data compiled from the scientific literature concerning copper self-diffusion is presented in this article, along with figures, tabular presentation of data, and discussion of results.
Abstract: A survey, comparison, and critical analysis is presented of data compiled from the scientific literature concerning copper self‐diffusion. Topics include volume diffusion, dislocation pipe diffusion, surface diffusion, sintering, electromigration, thermomigration, pressure effect on diffusion, strain‐enhanced diffusion, nuclear magnetic resonance measurements of solid state diffusion and diffusion in molten copper. An extensive bibliography is presented along with figures, tabular presentation of data, and discussion of results.
TL;DR: In this paper, a new copper (+III) compound, SrLaCuO 4 has been prepared under oxygen pressure and investigated, and it has the K 2 NiF 4 structure (a = 3.765 ± 0.002 A c = 13.27 ±0.02 A).
TL;DR: The use of benzotriazole as a corrosion inhibitor is briefly reviewed and the theory of its mode of protection for copper in aqueous conditions is considered as discussed by the authors, and it has been shown to be a good inhibitor for copper and brass when added to many acidic, neutral and alkaline solutions, and it appears to act as a weak buffer.
Abstract: The use of benzotriazole as a corrosion inhibitor is briefly reviewed and the theory of its mode of protection for copper in aqueous conditions is considered. The solubility has been found to increase with temperature, and the addition of benzotriazole decreased the pH and increased the conductivity of distilled water. It has been shown to be a good inhibitor for copper and brass when added to many acidic, neutral, and alkaline solutions, and it appears to act as a weak buffer. Copper surfaces pretreated with a hot solution of benzotriazole were found to have an increased resistance to staining in atmospheric environments and also to corrosion when immersed in many solutions of acids and salts. The inhibitor reduced the dissolution of copper in water and thus the pitting of aluminum foil immersed in the same water.
TL;DR: In this article, the Schiff base S-methyl-β-N-(2-hydroxyphenyl)methylendithiocarbazate, o -HO.
TL;DR: The three solvates are different in structure and in their fluorescence colour in ultraviolet light as discussed by the authors, and the last one is spontaneously decomposed by benzene to form highly dispersed copper iodide which fluoresces red at room temperature but not at all in liquid nitrogen.
Abstract: Copper(I)iodide reacts with pyridine to form (Cu py)I, and further to form (Cu py2)I. A tripyridino compound, although existing in contact with pyridine, is not obtainable at room temperature and normal pressure.
The three solvates are different in structure and in their fluorescence colour in ultraviolet light.
(Cu py3)I crystals are not fluorescent at room temperature but show yellow fluorescence at −180°C. (Cu py2)I is fluorescent with a green colour at room temperature as well as at very low temperatures. (Cu py)I shows yellow fluorescence at room temperature which reversibly changes to orange, then to red and finally to violet by cooling in liquid nitrogen („fluorescence thermochromism”). The last named compound is spontaneously decomposed by benzene to form highly dispersed copper iodide, which fluoresces red at room temperature, but not at all in liquid nitrogen.
TL;DR: In this article, the surface potential values for annealed polycrystalline films of copper and silver are consistent with those already reported for a pre-painted polycrystaline film of copper, indicating that the latter is not specifically related to surface roughness.
TL;DR: In this article, a model was developed to predict the wetting behavior between carbon and copper alloys containing 1 at.15 at. % chromium or vanadium and as much as 13 at.
Abstract: In a previous paper (J. Mater. Sci.5 (1970) 149) a model was developed to predict the wetting behaviour between carbon and copper alloys containing 1 at. % of a carbide forming element. In the present paper it is shown that the model can be applied successfully to alloys containing as little as 0.15 at. % chromium or vanadium and as much as 13 at. % titanium. A further development of the model is its use to predict carbide surface energies, the values derived being in good agreement with literature data.
TL;DR: The detailed kinetics of the reaction suggest a mechanism which involves substitution of thiosulphate ion into the co-ordination sphere of a triamminecopper(II) complex in the rate-determining step as discussed by the authors.
Abstract: Copper(II) ions in aqueous ammonia solution oxidize thiosulphate ions initially to tetrathionate ions; the latter then undergo a subsequent disproportionation reaction to yield trithionate and thiosulphate ions. The detailed kinetics of the reaction suggest a mechanism which involves substitution of thiosulphate ion into the co-ordination sphere of a triamminecopper(II) complex in the rate-determining step. A one-equivalent electron transfer from the thiosulphate to the copper(II) ion, occurring in the intermediate triamminecopper(II)–thiosulphate complex, gives rise to copper(I) and S2O3– ions, the latter dimerizing to tetrathionate ions.
TL;DR: In this paper, the effect of benzotriazole on the corrosion of copper in 3% NaCl at pH3 has been studied by immersion tests, potentiostatic polarization, a.c. impedance measurements and ellipsometric investigations.
Abstract: The effect of benzotriazole on the corrosion of copper in 3% NaCl at pH3 has been studied by immersion tests, potentiostatic polarization, a.c. impedance measurements and ellipsometric investigations. Results show that a thin layer of BTA forms in neutral solutions but that, in acidic solutions, the film is covered with a porous salt film which can be easily wiped off. Results seem to indicate that BTA interacts with the copper surface only when it is covered with some oxide. See also AATA 9-379. -- AATA
TL;DR: The steady creep rate for polycrystalline copper at 686, zinc at 385, and iron at 923 K varies as the nth power of the applied stress (σ) as discussed by the authors.
Abstract: The steady creep rate, e s , for polycrystalline copper at 686, zinc at 385, and iron at 923 K varies as the nth power of the applied stress (σ). The value of n was 4.8 for copper and zinc but was 8.3 for iron. Stress-relaxation tests and constant-stress tests in which the stress was progressively reduced gave values of a ‘friction’ stress, σ0, such that for all materials examined ɛ ˙ s ∝ ( − σ 0 ) 4 In all cases, decreasing the stress by a small amount, (∆σ, ≃ 0.1 σ) during steady-state creep resulted in an incubation period of zero creep rate, after which the creep rate increased to a new steady value. When the stre...
TL;DR: In this article, equilibrium relations and corresponding potential-pH diagrams for copper in sea-water are presented, on the basis of a critical analysis of the available activity coefficient data, and the competitive precipitation of atacamite and malachite is pointed out.
TL;DR: In this article, conditions for the formation of copper hydrous oxide dispersions of uniform size and shape are described, and the results show that these particles show cubic crystal symmetry characteristic of Cu 2 O, although their habit changes from cubic, through cuboctahedral to octahedral as the average particle size increases.
TL;DR: In this article, the temperature variation of the hydrogen solubility of copper, silver, and gold in equilibrium with H2-gas at atmospheric pressure has been measured, and values for the relative partial enthalpy and partial excess entropy of the interstitially dissolved hydrogen atoms have been estimated from the Solubility data.