دانلود رایگان ترجمه مقاله مدل ریاضی برای رمزگذاری الکترولیتی ذرات با ماتریس فلزی (نشریه الزویر 1986)

مدل ریاضی برای رمزگذاری الکترولیتی ذرات با ماتریس فلزی

A Mathematical Model for the Electrolytic Codeposition of Particles with a Metallic Matrix

Abstract

Over the last decade the general knowledge of the electrolytic codeposition of inert particles with metals has increased markedly, and a few models have been proposed. In this paper a new model that overcomes several of the shortcomings of the previously proposed models is developed starting from a statistical approach of the incorporation of particles. The validity of the new model is shown for two experimental codeposition systems, namely, Cu-A1203 from acidic sulfate baths and Au-Al~O3 from additive-free potassium cyanide baths.

In the early days of composite plating most attention was directed toward practical problems; few efforts were made to elucidate the mechanism of codeposition. Three possible mechanisms were put forward, namely: electrophoresis proposed by Whithers in 1962 (1), mechanical entrapment suggested by Martin in 1964 (2), and adsorption of particles on the cathode mentioned by Brandes (3) in 1967. Various investigators (4, 5) measured the zetapotential in dilute solutions. Since in electrolytic codeposition solutions of high ionic strength usually are used, extrapolation from dilute solutions gives no reliable evidence of possible electrophoretic effects. Based on a mass transport analysis toward rotating disk electrodes, it was calculated by Van Camp (6) that particles will not reach the surface of a rotating electrode by inertial forces alone as long as

where p, = specific weight of particles, d = diameter of particles, ~o = rotation speed of the electrode, and v = kinematic viscosity. Concerning a possible adsorption effect of particles onto the cathode by Van der Waals attractive forces, Tomaszewski (7) was the first to point out the effect of monovalent cations on the codeposition process, e.g., thallium ions drastically promote the amount of codeposited particles from copper sulfate plating baths, as was confirmed later by different researchers (8-10). In this respect Foster et al. (10) reported a very low degree of adsorption of copper ions on alumina particles, which was supposed to be associated with the rather poor degree of codeposition. However by the addition of tetra ethylene pentamine and especially Tl+-ions, ad- *Electrochemical Society Active Member. sorption and codeposition behavior improved drastically.