Copper single-crystal

Calculations of this type are carried out for fee, bcc, rock salt, and hep crystal structures and applied to precursor decay in single-crystal copper, tungsten, NaCl, and LiF [17]. The calculations show that the initial mobile dislocation densities necessary to obtain the measured rapid precursor decay in all cases are two or three orders of magnitude greater than initially present in the crystals. Herrmann et al. [18] show how dislocation multiplication combined with nonlinear elastic response can give some explanation for this effect. 

The shock-induced micromechanical response of <100>-loaded single crystal copper is investigated [18] for values of (WohL) from 0 to 10. The latter value results in W 10 Wg at y = 0.01. No distinction is made between total and mobile dislocation densities. These calculations show that rapid dislocation multiplication behind the elastic shock front results in a decrease in longitudinal stress, which is communicated to the shock front by nonlinear elastic effects [pc,/po > V, (7.20)]. While this is an important result, later recovery experiments by Vorthman and Duvall [19] show that shock compression does not result in a significant increase in residual dislocation density in LiF. Hence, the micromechanical interpretation of precursor decay provided by Herrmann et al. [18] remains unresolved with existing recovery experiments. 

Figure 9.8. Sintering of single-crystal copper spheres to a single-crystal copper substrate.

Due to the experimental difficulties involved, there have been only three reports of XSW measurements at electrochemical interfaces. Materlik and co-workers have studied the underpotential deposition of thallium on single-crystal copper electrodes under both ex situU9 and in situ120 conditions. In addition, they report results from studies in the absence and presence of small amounts of oxygen. 

Figure 5.16 Resolved shear stress as a function of dislocation density for copper. Data are for polycrystalline copper O single-crystal copper with one slip system operative 0 single-crystal copper with two slip systems operative and A single-crystal copper with six slip systems operative. From K. M. Rails, T. H. Courtney, and J. Wulff, Introduction to Materials Science and Engineering. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission John Wiley Sons, Inc.

Monolayer structures and epitaxial growth of vapor-deposited crystalline phthalocyanine films on single crystal copper substrates were studied using low energy electron diffraction Ordered monolayers of three different phthalocyanines, copper, iron, and metal-free, were seen on two different faces of copper, the (111) and (100). The monolayer structures formed were different on the two crystal faces and the several phthalocyanines yield nonidentical monolayer structures. 

V.Y. Doo and R.W. Balluffi. Structural changes in single crystal copper-alpha-brass diffusion couples. Acta Metall, 6(6) 428-438, 1959. 

Argon on graphite, at higher 0 values, shows the same behavior as nitrogen on single-crystal copper, as has been described above 223). The mutual van der Waals attraction forces may, in this case, lead to two-dimensional condensation, as is also shown by the entropy data. We shall discuss two-dimensional condensation in Sec. VIII,4. 

M.F. Florstemeyer et al Torsion/simple shear of single crystal copper. J. Eng. Matls. Tech. 

Fig. 27. Oxidation isotherms of single crystal copper surfaces 78-323°K O run No. 1 run No. 2. Samples No. 1 to No. 24 of crystal faces (100), (110), and (111). Isotherms curves are calculated. [After Rhodin, J. Am. Chem. Soc. 73, 3143 (1951).]...

The observed roughness factors (ratio of true to geometric surface) of the surfaces employed in this study varied from 1.2 to 1.4 (Table IV). This checked with electron microscope pictures of alumina and silica replicas from electropolished single crystal copper surfaces. It is unlikely that the surface areas determined by the Brunauer-Emmett-Teller analysis are too high by 50% or even by 25%, because in several cases this would lead to a roughness factor of less than unity. 

Fig. 33. Some possible positions of a nitrogen molecule physically adsorbed on single crystal copper surfaces. (Projections are constructed to scale in directions normal and parallel to the substrate. Copper atoms are schematically indicated as rigid close packed spheres and nitrogen molecules as spherical pairs.) [After Rhodin, J. Am. Chem. Soc. 72, 5691 (1950).]...

The isosteric differential heats of physical adsorption of nitrogen near its boiling point on reduced and oxidized electropolishing single crystal copper surfaces can be evaluated from adsorption isotherms determined gravimetrically. 

In recent years, many papers have been published dealing with the interaction of acetylene with the low index single crystal copper (lll)[6-8, 13-15], (110)[9,16,17] and (100)[ 17-29] surfaces. 

The studies of Ertl and associates employed a surface consisting of the (0001) face of a ruthenium single crystal. Copper was deposited on the ruthenium surface by exposing the surface to a flux of copper atoms obtained by evaporation of a copper source. From low energy electron diffraction, Auger electron spectroscopy, thermal desorption, and work function measurements (18) Ertl and associates concluded that copper deposits on the ruthenium surface at 540 K in the form of a two-dimensional overlayer to coverages of 50 to 60%, beyond which there is a transition to a three-dimensional growth phase. 

Carbon ion implantation on a single crystal copper surface at a temperature of 820°C, an ion dose of 10 ions cm and a beam energy of 65 to 120 keV was found to result in an enhancement of diamond nucleation. The nucleation enhancement was postulated to be due to the formation of a graphite film on the copper sur ce, with subsequent diamond nucleation occurring preferentially on the edges of the graphite lattice. 

T. P. Ong, F. Xiong, R. P. H. Chang, and C. W. White, Mechanism for diamond nucleation and growth on single crystal copper surfaces implanted with carbon, Appl Phys. Lett., 60(17) 2083-2085 (1992)... 

Table 9-2 lists some characteristic coefficients of friction for metals sliding in vacuum environments in which the average levels of pressure lie in the range 400-1330 nPa. But before deciding that surface cleanliness is the controlling influence in the friction of unlubricated metals, some consideration should be given to the data in Table 9-3 and to the behavior of single-crystal copper sliding on the (111) face (Table 9-1). It is quite apparent that the frictional process for sliding met-...

R.M. Nix and R.M. Lambert. Surface Crystallography and Growth Modes of Rare Earth Metals and Alloys on Single Crystal Copper Nd on Cu(OOl). Surf. Sci. 186 163 (1987). 

A. Bruckbauer and A. Otto, Raman Spectroscopy of Pyridine Adsorbed on Single Crystal Copper Electrodes, J. Raman Spec-trosc. 29, 665 (1998)... 

For some active metals, the flame annealing method carmot be used, and the electrochemical poKshing method comes to the fore. For example, a good single crystal copper surface can be obtained by electrochemical polishing for 20 s in a solution of 60% H3PO4 in water, at 2.0 V. For most crystal surfaces, in order to help preserve the perfectness of the surface, the electrode is normally immersed into a solution with potential control. 

Fig. 1. MD simulation model of nano cutting on single crystal copper surface.

Fig. 2. The chip deforming of single crystal copper scratched on (010) plane by triangular-based pyramid tool with -60°rank angle. Arrow shows chip deforming.

The workpiece crystal orientations also have important effects on defects evolvement, as shown in Fig. 7. When the AFM diamond tip scratches the surface of single crystal copper as shown in Fig. 7(a), it can be seen that dislocation is prone to nucleate ahead the tool, and those dislocations glide in the [101] direction as the effects of the edge of the AFM diamond tip. The Fig. 7(b) shows the case of (110) plane of single crystal copvper. From the Fig. 7(b), it is found that dislocations glide in the [-101] direction. For the case of (111) plane of single... 

Figure 2 Copper oxidation. Oxidation of single-crystal copper surfaces in an atmosphere of oxygen at 70°C. (From Ref. 13.)...

Grider has studied photoemission from copper with adsorbed Br, F, ion, thiourea, and pyridine. He proposed that the major effect attributable to adsorption of halide ions and thiourea was partial relaxation of the conservation of electron momentum parallel to the surface. In the case of R4N ion adsorption, the structure of the yield ratio of photocurrents produced by p-and -polarized light shifted with photon energy, and this was explained by an increase in the local density of electrons near the surface due to the adsorption, which can cause scattering effects. Pyridine, upon adsorption, similarly affected the yield ratio structure at bulk concentrations >10 M, but a clear understanding of this result remains to be attained. Grider et also have provided evidence that partial relaxation of parallel momentum conservation occurs for in situ photoemission from a single-crystal copper... 

---