Copper self-diffusivity

Since this type of dependence is also common for diffusion, one can presume that the observed phenomenon is of diffusion nature. In this case diffusion coefficient Do, calculated from (17), is equal to 10000 cnrfi/ s, that is two orders of magnitude more than specified in reference books copper self-diffusion coefficient, which is 70 crrfi/s. 

The dififiision time gives the same general picture. The bulk self-diffusion coefficient of copper is 10"" cm /sec at 725°C [12] the Einstein equation... 

He studied the sintering of copper particles in the diameter range 15-100 microns and of silver particles of diameter 350 microns. The results for the larger volume fraction of copper and for silver were shown to fit the volume diffusion mechanism and yielded the results for volume self-diffusion... 

Quite extraordinary diffusion coefficients of impurities from odier parts of die Periodic Table are found, and especially in die important case of lidiium or copper diffusion, where die eidiancement over self-diffusion is by six to eight orders of magnitude. This indicates diat diese atoms do not form part of die sp network in die sUmcture, but more closely resemble separate atoms in die sp iiiaUix. 

Diffusion of Self-Interstitial Imperfections by the Interstitialcy Mechanism in the F.C.C. Structure. For f.c.c. copper, self-interstitials have the (100) split-dumbbell configuration shown in Fig. 8.5d and migrate by the interstitialcy mechanism illustrated in Fig. 8.6. The jumping is uncorrelated,8 (f = 1), and a/ /2 is the nearest-neighbor distance, so... 

The first high-pressure NMR studies were performed by Benedek and Purcell in the mid nineteen-fifties. They discovered that the beryllium-copper alloy Berylco-25 is nonmagnetic and that it is very suitable for high-pressure equipment for magnetic studies. Their pressurizable NMR probe (see Fig. 4.19) was similar to designs used today, and it was used at pressures up to 1 GPa (10000 atm) to study the variation with viscosity of proton relaxation times and self-diffusion eonstants in a series of liquids. Since then a variety of systems for variable-pressure experiments have been developed. Three basic approaches have been used ... 

Evangelakis, G.A., Papanicolaou, N.l. Adatom self-diffusion processes on (001) copper surface by molecular dynamics. Surf. Sci. 1996,347,376. 

The radioactive indicator method has been used in just the same way to follow the diffusion of lead ions in lead chloride and lead iodide (32). With the discovery of artificial radioactivity the method seems capable of very wide application indeed. Gold, for example, has been rendered radioactive by neutron bombardment, and then used (33) to measure the selfdiffusion constant of gold in gold and radioactive copper has been used to measure self-diffusion in copper (33a). Some of the substances which may be rendered radioactive by bombardment with neutrons, deuterons, protons, or y-rays, and whose half-life period seems adequately long for the duration of possible diffusion experiments, have been collected in Table 59. 

Those diffusion systems which have been marked with an asterisk in Table 67 represent metal pairs which form a continuous series of mixed crystals. As a rule in such systems the value of is small, an important exception being selfdiffusion processes (Pb in Pb iDq = 5-1 cm. sec." Au in Au Do = 1-26 X lO cm. sec." ). The normal range of values of Dq lies between 10 and 10 cm. sec.". There are exceptions, however for example, the diffusions of silicon and tin into copper give = 1-Ox 10 and 6-7 x 10 cm. sec. . Dq for the self-diffusion of bismuth, in a direction perpendicular to the c-axis, reaches a value of (1-33—16-3) x 10. It is difficult to assess the reproducibility of some of the data, since some of the diffusion processes listed are structure sensitive, but those for bismuth appear reasonably consistent (see Fig. 100). It is to be noted that the higher the... 

Kingery et al. [10a] have collected the experimental results for cation and anion self-diffusion coefficients in various oxides. For instance, the rate of diffusion of copper in CU2O, a modifier, is six orders of magnitude larger than that of aluminum in AI2O3, a network former when the aluminum is four coordinate. This result is for a temperature of approximately 1500°C, but the relative relationship is expected to hold at room temperature. This finding also supports the postulate that network modifiers can recrystallize more easily than network formers. 

Liu X, Wang Q, Wu S, Liu Z (2006) Enhanced CVD of copper films on self-assembled monolayers as ultrathin diffusion barriers. J Electrochem Soc 153(3) C142-C145... 

CSM grids are not suitable for positive plates because the corrosion wiU quickly eat up the lead layer covering the grid and copper ions will diffuse to the solution and thus reduce the charge efficiency and accelerate greatly the self-discharge processes. 

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