Open AccessThe polarization of zinc electrodes in neutral and acid solutions of zinc salts by direct and alternating currents.—Part. I
Author(s) -
A. J. Allmand,
H. C. Cocks
Publication year - 1926
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1926.0110
Subject(s) - alternating current , zinc , anode , electrode , electrolysis , direct current , chemistry , polarization (electrochemistry) , superposition principle , analytical chemistry (journal) , cathode , inorganic chemistry , voltage , electrical engineering , electrolyte , physics , chromatography , organic chemistry , quantum mechanics , engineering
In the preceding paper it was shown that an amalgamated Line electrode made anode in an anode zinc sulphate solution undergoes considerable polarisation, and that tins polarisation can be more than overcome by the superposition of a sufficiently large alternating current of high frequency. Further, Allmand and Puri mention experiments in which a cathode of amalgamated zine had superposed on it alternating currents of intensities up to 200 times that of the direct current, and of frequencies varying between 20 and 400, the effect being to increase the polarisation of the electrode, which became more negative. These results were not to be anticipated from previous work, and it seemed that a closer investigation of the whole subject might not only explain the facts referred to, but perhaps throw fresh light on the mechanism of the electrode processes involved. As possible factors affecting the phenomena could be considered the amalgamation or otherwise of the zinc electrode, the presence or absence of free acid in the solution, the nature of the zinc salt (e. g. , whether sulphate or chloride), duration of electrolysis, temperature, the absolute and relative values of the direct and alternating current densities, and tbs frequency of the alternating currents. The present paper contains an investigation of some of these points, working at room temperature and with zinc sulphate solutions, potential measurements have been made with amalgamated zinc electrodes in absence and in presence of free H2 SO4 , and with unamalgamated electrodes in neutral solution. Alternating currents and compound currents have been used, and a few experiments made with direct currents, frequencies varying between 50 and 11,000 have been worked with.