Frequency Dependence of Polarisation Resistances Measured with Squarewave Alternating Potential

Abstract

Polarisation resistance measurements have been made on iron and aluminium electrodes in a selection of common inorganic electrolytes. A square-wave alternating potential was applied to the electrodes over the frequency range 0·03–10⁴ Hz. The electrode impedance deviated from a pure resistance to varying extents the measured value of polarisation resistance varying significantly with frequency over the entire frequency range in some cases. Transient effects at high frequencies, which cause distortion of the waveform, may be minimised by the use of a control circuit of low impedance.