USE OF THE HARING CELL FOR MEASURING ADDITION AGENT CONCENTRATION IN ELECTROLYTIC BATHS

Abstract

Cathode polarization measurements during electrodeposition from acid copper sulphate solutions were made with a Haring cell, using a method previously developed (4). Measurements made at 2°, 24.8°, and 50.1 °C. show that the polarization decreases as temperature increases, this decrease being larger for a temperature change from 2° to 24.8 °C. than for a change from 24.8 to 50.1 °C. An increase in acidity has little effect on the polarization (except for low acidities) at apparent current densities below 2 amp. per dm.2, while it results in an increase in polarization above that value. The increase in polarization caused by various concentrations of gelatin was studied at −4.2°, 2°, 24.8°, and 50.1 °C. For a given gelatin concentration, the increase in polarization is greater the lower the temperature, while for a given temperature, the relative increase in cathode polarization is greater at smaller gelatin concentration. It is concluded that control of the gelatin or glue concentration of an electrolyte with a Haring cell may be considerably improved by making the measurements at low temperatures and in dilute solutions.