Polycrystalline copper

Mintz M H, Atzmony U and Shamir N 1987 Initial adsorption kinetics of oxygen on polycrystalline copper Surf. Sc/. 185 413-30... 

Cemented tungsten carbides also find use as a support for polycrystalline diamond (PCD) cutting tips, or as a matrix alloy with cobalt, nickel, copper, and iron, ia which diamond particles are embedded. These tools are employed ia a variety of iadustries including mineral exploration and development oil and gas exploration and production and concrete, asphalt, and dimension stone cutting. 

Other vicinal planes of copper single crystals and polycrystalline copper have been investigated and are also found to synthesize methanol in similar amounts as the Cu(lOO) surface [H. Nakano, I. Nakamura, T. Fujitani and J. Nakamura,/. Phys. Chem. B 105 (2001) 1355 Yoshihara and C.T. Campbell, J. Catal. 161 (1996) 776],... 

Figure 8.14. Turnover frequency for methanol synthesis from H2 and CO2 at 18 bar and 523 K as a function ofZn coverage on polycrystalline copper. [From j. Nakamura, I. Nakamura,...

Electrodeposition of copper indium disulfide (CulnS2) has been reported [180-182], In a typical instance, single-phase polycrystalline CuInS2 thin films composed of 1-3 fim sized crystallites were grown on Ti by sulfurization of Cu-ln precursors prepared by sequentially electrodeposited Cu and In layers [183]. In this work, solar cells were fabricated by electrodepositing ZnSe on CuInS2. Cyclic... 

It is particularly helpful that we can take the Cu-Ni system as an example of the use of successive deposition for preparing alloy films where a miscibility gap exists, and one component can diffuse readily, because this alloy system is also historically important in discussing catalysis by metals. The rate of migration of the copper atoms is much higher than that of the nickel atoms (there is a pronounced Kirkendall effect) and, with polycrystalline specimens, surface diffusion of copper over the nickel crystallites requires a lower activation energy than diffusion into the bulk of the crystallites. Hence, the following model was proposed for the location of the phases in Cu-Ni films (S3), prepared by annealing successively deposited layers at 200°C in vacuum, which was consistent with the experimental data on the work function. 

Figure 4.4 Left sputter yields of copper under bombardment with Ne, Ar, Kr and Xe ions as a function of energy (data from [2]). Right, relative sputter yields of polycrystalline copper as a function of incident angle measured from the surface normal. The primary ion energy is 1.05 keV. The dashed line represents 1/cos (adapted from Oechsner [8]).

A.M. Meier et al., A Comparison of the Wettability of Copper-Copper Oxide and Silver-Copper Oxide on Polycrystalline Alumina, J. Materials Science, 30[19] pp. 4781 4-786 (1995). 

Thus, besides being sensitive to absorbing species on the electrode surface as well as in the solution in the region very close to the surface, it is possible to obtain potential dependent behavior in fine detail. We have applied these techniques to examine the interaction of simple ions such as CN and Ny with polycrystalline electrodes of silver, gold and copper. The observed vibrational spectra can be interpreted with the help of selection rules based on symmetry and analysis of ab-initio SCF wavefunctions of clusters. The results of these studies will be reviewed. 

All SERS experiments were conducted with a polycrystalline silver working electrode prepared by press-fitting a 6 mm diameter cylinder of silver into one end of a 0.375 inch diameter Teflon rod through which a 6 nm diameter concentric hole had been drilled. Electrical contact was made via a copper wire soldered to the silver. The geometric area of the silver disk was 0.28 cm2. 

These studies were with polycrystalline copper, but more detailed results (Fig. 9) were obtained subsequently (44) with Cu(100), Cu(l 11), and Cu(l 10) surfaces XPS, UPS, LEED, and mass spectrometric data being combined to provide a self-consistent model. The surface species formed with their associated N(ls) and 0(ls) binding energies (eV) on exposing copper surfaces to NO(g) are listed in Table I. 

There were small but experimentally insignificant differences between binding energies observed with polycrystalline and different crystal planes of copper. We have assigned the two quite distinct N(ls) peaks at 399.5 and 401 eV to bent [NO(b)j and linearly [NO(/)j bonded molecular... 

Figure 7.19. The four basic deposit structural forms of Cu deposited on Cu(lOO) face from acid copper solutions a) ridge b) platelet (c) block (d) polycrystalline. (From Ref. 44, with permission from Elsevier.)...

Hathaway has attempted to assess the value of the electronic properties of polycrystalline mononuclear copper complexes with the [CUN4], [CuNj], and [CuN ] chromophores of unknown crystal structure, in predicting the stereochemical environment of the copper(ii) atom. The value of having B. J. Hathaway, J.C.5. Dalton, 1972, 1196. 

Reduction of substituted nitrobenzenes under alkaline conditions, usually with aqueous sodium acetate as electrolyte and a nickel cathode, is the classical method due to Elbs [45] for the formation of azo- and azoxy-compounds. Protons are used in the electrochemical reaction so that the catholyte becomes alkaline and under these conditions, phenylhydroxylamine reacts rapidly with nitrosobenzene to form azoxybenzene. Finely divided copper has long been known to catalyse the reduction of nitrobenzene to aniline in alkaline solution at the expense of azoxybenzene production [46]. Modem work confirms that whereas reduction of nitrobenzene at polycrystalline copper in alkaline solution gives mainly azoxybenzene, if the electrode is pre-oxidised in alkaline solution and then reduced just prior to the addition of nitrobenzene, high yields of aniline are obtained with good current efficiency... 

Both the copper and nickel surfaces are efficient for the electrochemical reduction of nitrobenzene to aniline. With time however, the properties of this surface are transformed to those of the polycrystalline metal and azoxybenzene becomes as major reduction product [49]. 

Electrodeposition of Cd on polycrystalline copper was analyzed from the point of view of oxide influence [299], and a comparison of electrochemical data with results of numerical calculations was presented. 

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