CORROSION RESEARCH ROUND‐UP

Abstract

CHROME PLATING Cathodic potential in make‐and‐break of polarisation current. In order to understand the mechanism of electro‐deposition of metals considerable importance attaches to the study of cathode potential changes observable in the short interval of time between switching on or off of the polarisation current, especially with chromium, as previous Russian workers have noted (literature references are mainly Russian). But these do not satisfactorily explain all the observed phenomena. This is here attempted by means of oscillographic recordings of cathode potential changes, as per method described, using a bath containing (g./l.): 250 CrO3 and 5 H2SO4. Micro‐photographs are given of the oscillograms and of chromium structure. It is shown that, on switching in the current, a cathodic film is formed which is adsorbed on the surface. This proceeds the more quickly the greater the current density and higher the temperature, also the lower the sulphate concentration. With rise in temperature there is more interaction between the film formed and the chromium deposit, depending on the structure of this latter. Under the most widely used conditions in general practice it is concluded that the film formation is almost instantaneous when the current is switched on and intimate interaction thereof with the cathode surface. Ten references.— (M. A. Shluger, Zh. prikl. Khim., 1960, 33 (6), 1355–1359.)

Citation

(1960), "CORROSION RESEARCH ROUND‐UP", Anti-Corrosion Methods and Materials, Vol. 7 No. 9, pp. 295-298. https://doi.org/10.1108/eb019768