U. Bertocci et al., NOISE RESISTANCE APPLIED TO CORROSION MEASUREMENTS .1. THEORETICAL-ANALYSIS, Journal of the Electrochemical Society, 144(1), 1997, pp. 31-37
The measurement of current and voltage fluctuations on the same electr
ochemical cell allows the evaluation of a quantity R(n) known as noise
resistance, which has been proposed as an indication of the corrosion
resistance of the material under study. The theoretical basis for the
relationship between R(n) and the electrode impedance Z is developed,
taking into account the various measurement schemes currently in use.
Parameters such as cell geometry, solution resistance, and electrodes
with different kinetics are considered. It is shown that, in general,
the modulus of the electrode impedance can be derived by measuring th
e power spectral densities (PSD) of the voltage and current noises. Th
e circumstances in which R(n) is equal to the polarization resistance
of the electrode are also discussed.