Linear Corrosion Kinetics at Dual Electrodes

It is shown analytically that dual electrodes have the general property of extended linear polarization relative to anode or cathode. The dual-electrode measurement of corrosion rate permits use of larger applied potentials with good accuracy. An inherent source of error in present measurements on non-identical electrodes is demonstrated, and a new method is proposed to avoid it. Experimental data on iron corrosion in an acid sulfate solution confirm extended linear polarization and the improved accuracy of the new method.