Showing papers on "Copper published in 1974"

A model for the fatigue of copper at low plastic strain amplitudes

Abstract: Single crystals of pure copper oriented for single slip were fatigued in air at room temperature at low constant plastic strain amplitudes in the range 0·1 % ≤ e p≤ 0·6%. After a few thousand cycles the specimens entered what appeared to be an equilibrium state which contained two phases: a hard and almost inactive ‘matrix’ and the softer ‘persistent slip bands’ (PSBs) into which the deformation tended to concentrate. In the equilibrium state the stress amplitude, the shape of the stress-strain loop and the volume fraction of the specimen occupied by the PSBs were invariant. Furthermore, the volume fraction occupied by the PSBs was found to be linearly related to the plastic strain amplitude. Thus, no matter what the average strain amplitude in the crystal (so long as both phases were present) the PSBs suffered a fixed amplitude which was measured as 0·90%; the specimen adapted itself to the applied amplitude by adjusting the relative amounts of the two phases. A number of predictions of this mod...

Catalyst for electroless deposition of metals

Abstract: A solvent method for the metallization of a non-conductive surface with gold, nickel or copper is shown whereby on a substrate a thermosensitive coordination complex of palladium is deposited; the complex has the formula LmPdXn wherein L is a ligand or unsaturated organic radical, X is a halide, alkyl group or a bidentate ligand and m is an integer from 1 to 4 and n is from 0 to 3; trimethyl phosphite palladium dichloride complex is an appropriate illustration of the complex; the palladium complex is applied on the substrate in a suitable non-aqueous solution such as tetrahydrofuran solution; the complex is then baked in air at elevated temperature; the exposure to high temperature decomposes the complex leaving a residue which is catalytic to the deposition of gold, nickel, cobalt or copper from an electroless bath thereof; the non-conductive material is then immersed in an electroless bath to metallize the areas which have been rendered catalytic; the preferred thermosensitive coordination complex of palladium is trimethyl phosphite palladium dichloride; a requirement for a proper thermal exposure of the complex is that the substrate is capable of withstanding the elevated temperatures such as above 210°C; illustrative organic substrates are polyimides, polysulfones, silicones, vulcanizates, fluoroplastics, polyphenylene sulfides, polyparabanic acids, and polyhydantoin, etc.

The work-hardening of copper-silica: IV. The Bauschinger effect and plastic relaxation

Abstract: Bauschinger data for dispersion-strengthened single crystals are given, and correlated with data on the dislocation microstructure and the softening effect which is prominent at room temperature in copper. The data are analysed in terms of theories presented in earlier papers, and the following conclusions have been reached: (i) the Bauschinger effect, suitably defined, can be quantitatively accounted for by the mean internal stress level in the copper matrix; (ii) the internal stress behaves as a function of strain and temperature in accord with the earlier theories, except that plastic relaxation requires a temperature-dependent initiation stress in alloys containing small particles; (iii) the softening process is the process of plastic relaxation, and is characterized by an activation energy of 0·9 eV and an activation volume of 1·5 b3; (iv) a new interpretation is given for the dislocation microstructures observed in the softened state; (v) the work-hardening in the unrelaxed state can be sep...

Effect of Complexation on Toxicity of Copper to Fishes

Abstract: Copper (Cu) is highly complexed by carbonate and hydroxide ions in natural waters and this complexation determines the concentration of copper species in solution. Results of detailed equilibrium calculations on data from bioassays where alkalinity, pH, hardness, and total copper concentration are different indicate that copper(II) is the chemical species that is toxic to fishes and that alkalinity is the factor controlling copper(II) concentration.

Isolation of heavy metal binding proteins from marine vertebrates

Abstract: Cadmium binding proteins have been isolated from liver homogenates of marine vertebrates by ultracentri fugation and gel filtration. Liver samples of the Atlantic grey seal Halichoerus grypus and the Pacific fur seal Callorhinus ursinus contain measurable quantities of cadmium binding protein. The copper rock fish Sebastodes caurinus showed an increase in hepatic cadmium binding protein on administration of CdCl2, in agreement with the known inducible nature of the protein isolated from terrestrial animals. The apparent molecular weights of the isolated proteins were 9000 for the grey seal, 10,000 for the fur seal, and 11,000 for the copper rock fish, as determined by gel filtration.

Copper(I) alkoxides. Synthesis, reactions, and thermal decompositions

Abstract: Alkoxides and phenoxides of copper(I) can be prepared by the heterogencous reaction between alcohols and phenols and methylcopper(I). These organocopper(I) compounds are useful reagents for the formation of ethers by displacement of hai ide from organic hal ides. The reaction of copper(l) alkoxidcs with aryl hal ides yields alkyl aryl ethers under part icularly mild iondit ions. Thermal decomposit ion of primary alkorycopper(l) reagcnts generates intermediate alkoxy radicals. Thermal clecomposit ion of secondary alkoxycopper(l) reagents apparently can take place either by a free-radical mechanism or by a mechanism tentat ively suggested to involve copper(I)-hydride as an intermediate. The structural factors determining which mechanism wil l predominate for a given compound have not been established' tTth. utit i ty of alkyland arylcopper(l) reagents in I organic synthesis is based on their h igh nucleophi l ic i ty toward carbon, and on their abi l i ty to take part in electron-transfer reactions.2-a They also show low basicity toward protons, an afff inity for carboncarbon double bonds, and an abi l i ty to coordinate wi th soft Lewis bases. Since the mechanisms by which copper(I) influences the reactivity of carbanions are not clearly understood, it is diff icult to predict the behavior of new types of organocopper( I ) compounds. Nevertheless, there is obvious reason to hope that organic derivatives of copper(I) other than those belonging to the wel l -explored class of compounds containing carbon-copper bonds might also show useful (1) Supported by the Nat ional Science Foundat ior l , Grants GP28586X ancl GP-14247, ancl by the Internat ional coppcr Rcsearch Associat ion. (2) J. F. Normant, S) 'nthesis,2,63 (1972); G' H. Posner, Org' React ' , 19, | (1972), (3) G. Br ihr ancl P. Burba in \"Methoden der organischen chemie\" (Houben-Weyl) , Vol . XI I I /1, E ' Mi , i l ler , Ed. , Georg Thicme Vcr lag, Stut tgart , 1970, p 731 f f . (4) O. A. Chal tyk ian, \"Copper-Catalyt ic React ions,\" A. E. Stubbs, t rans. , Consul tants Bureau, New York, N' Y. , 1966; P. F. Fanta, Chem. Rec, ,64,613 (1964); R. G. R. Bacon and H. A. O. Hi l l ' Quart ' Rec. , Chem. Soc. , 19,95 (1965); J. Peisach, P. Aisen, and W. E' Blurnberg, Ed., \"The Biochemistry of Copper,\" Academic Press, New York, N . Y . . 1966 . react iv i ty. This paper descr ibes studies of one such class: a lkoxides of copper( l ) . These studies had three object i ies: synthesis and character izat ion of a lkoxides und phenox ides o f copper ( l ) ; de termina t ion o f the behar l ior of thesc substances in react ions whose usefulness with alkylcopper reagents has already been establ ished: and examinat ion of the mechanisms of their thermal decomposi t ion. Copper( l ) a lkoxides and phenoxides have been impl icated previously as intermediates in a var iety of copper-catalyzed react ions,a '5 and poor ly character ized examples of these substances have been prepared'6 A useful synthesis of copper([) tert-butoxideT is not appl icable to the preparat ion of the thermal ly unstable copper( I ) pr imary and secondary alkoxides that were of ^central interest in our work. The preparat ion of copper( I ) phenoxide by a procedure analogous to that descr ibed here has been reported.s Copper( I ) a lkoxides (5) J. K. I (ochi , Proc. I t t t . Congr. Pure Appl ' Chem', 23rd,4 ' 377 (1971), and referenccs citcd therein, (6 ) b . E . H . Bawr r and F . J . Wh i tbv , J . Chem.9oc . ,3926 (1960) ; G ' Costa. A. Camus, and N. Marsich, J. Inorg ' l ' ' luc l ' Chem',27' 281 ( I e6s ) . (7) T. Saegusa, T. Tsucla, and T. Hashirnoto, J ' Amer ' Chem' Soc\" 94 ,658 (1972) . iSl f. I(awaki and H. Hashimoto, Bull. Chem. Soc' Jap', 45, 1499 (r972). Whitesides, et al, I St'nthesis ttf Cttpper(l) Alkoxides

ESR of Cu2+(H2O)6. II. A quantitative study of the dynamic Jahn‐Teller effect in copper‐doped zinc Tutton's salt

Abstract: The X‐band ESR spectra of 63Cu2+ doped zinc Tutton's salt enriched to 16 at.% in 17O isotope was studied in a single crystal at 20, 77, and 290°K. The powder spectrum of the same material was studied over the temperature range 10–350°K at X band and 120–290°K at Q band. The observed values of the g tensor and 63Cu and 17O hyperfine tensors were found to be strongly temperature dependent except when the magnetic field was parallel to g3, one of the principal axes of the g tensor. The directions of the principal axes of the g tensor and 63Cu hyperfine tensor were shown to be temperature independent, in opposition to the findings of other workers. In the single crystal, marked mI dependent linewidth variations in the 63Cu hyperfine components were observed in the temperature range 14–80°K, except when the external field was parallel to g3. The experimental data are explicable in terms of a dynamic Jahn‐Teller effect, in contrast to the previously held assumption that dilute copper Tutton's salt is a static Jahn‐Teller system. The energy splittings between the three inequivalent valleys were determined directly from the experimental results and found to be δ1,2 = 75 cm−1, δ1,3 ≃ 450 cm−1. The splittings are discussed in terms of published crystallographic data on Tutton's salts, and a crystal field calculation gave a value of δ1,2/δ1,3 = 1/5 in good agreement with experiment. The rate of intervalley jumping between the lowest two valleys was determined from linewidth measurements and found to be characteristic of an Orbach process, following the law τ = τ0 exp(120/k T). The value of 120 cm−1 is identified with the height of the ``warping'' barrier between valleys 1 and 2. Phonon‐assisted tunneling makes no significant contribution to the jumping rate.

Composition and Stability of Iron and Copper Citrate Complexes in Aqueous Solution

Abstract: The acidity constants of citric acid and the stability constants of the citrate complexes of copper(II), iron(II), and iron(III) have been measured at 25 °C in 0.1 M KNO3 background. The measuremen...

The thermal decomposition of calcium, sodium, silver and copper(II) acetates

Abstract: The thermal decomposition of the acetates of calcium, sodium, silver and copper(II) have been investigated using thermogravimetry and differential thermal analysis, together with analysis of the gaseous products formed during the decomposition process. The results indicate that the major organic product formed is either acetone or acetic acid, depending on whether the final solid product is the oxide or the metal.

A kinetic theory of atomisation for non-flame atomic-absorption spectrometry with a graphite furnace. The kinetics and mechanism of atomisation for copper

Abstract: A kinetic approach has been made to the atomisation process in nonflame atomic-absorption spectrometry. Time-absorbance profiles for the determination of copper, using a graphite furnace, have been investigated in the temperature range 1720 to 2220 K and a rate equation derived that describes the variation of the amount of copper atoms in the furnace with time. It has been shown that a slow first-order reaction involving reduction of copper oxide by carbon followed by the rapid vaporisation of the copper formed is the most probable reaction mechanism. The greater sensitivity achieved in the determination of copper using a tantalum-lined graphite furnace has been attributed in part to the greater rate of reduction of copper oxide by tantalum.

Cohesion margin of copper

Abstract: Measurements on the mechanical properties of copper-bismuth alloys show that the only effect of bismuth within the solid solution range is to reduce the true tensile strength of the alloys—there is no detectable effect on plastic behaviour or on the elastic limit. Intergranular fracture occurs by the formation of grain boundary crack nuclei, these being seen in alloys containing as little as 0·002 wt.-% Bi. In addition, by measuring the effect of bismuth on surface and grain boundary energies of copper, it is shown that bismuth is present at the grain boundaries at monolayer levels, as true Gibbs segregation. It appears that the brittleness is due simply to reduced grain boundary cohesion. The measured relative cohesion of the copper-bismuth alloy is approximately half that of pure copper: such a reduction in grain boundary cohesion therefore converts ductile copper into a brittle metal, and thus defines a margin of cohesion. Reduced grain boundary cohesion favours the nucleation of cracks where ...

Diffusion in Copper and Copper Alloys, Part II. Copper‐Silver and Copper‐Gold Systems

Abstract: A survey, comparison, and critical analysis is presented of data compiled from the scientific literature concerning diffusion in copper‐silver and copper‐gold systems. Here the term ``copper alloy system'' is interpreted in the broadest sense. For example, the review of diffusion in the Cu‐M system reports all diffusion situations which involve both copper and element M, including diffusion of Cu in M or in any binary, ternary, or multicomponent alloy containing M: diffusion of M in Cu or in any alloy containing Cu; and diffusion of any element in any alloy containing both Cu and M. Topics include volume diffusion, surface diffusion, grain boundary diffusion, tracer diffusion, alloy interdiffusion, electromigration, thermomigration, strain enhanced diffusion, and diffusion in molten metals. An extensive bibliography is presented along with figures, tabular presentation of data and discussion of results.

Metal loss to slag: Part I. Sulfidic and oxidic dissolution of copper in fayalite slag from low grade matte

Abstract: An experimental technique to prepare slags free from suspended matte was developed and applied to measure the solubility of copper in Fe- and SiO2-saturated fayalite slag at 1200°C. The copper solubility was found to be considerably greater than that attributed to oxidic loss assessed from the work of Ruddleet al and also greater than that in previously-studied slags containing sulfur together with lime or alumina. The solubility was related to the presence of sulfur in the slag, and the concept of sulfidic dissolution was developed on the basis of thermodynamic properties of matte and slag. The model was applied to commercial slag-matte systems, and the reduction of sulfur solubility by changing the slag composition was concluded to be the key in reducing copper losses to slag, especially for mattes containing less than 50 pct Cu.