Abstract
In order to establish a fundamental interpretation of the etching mechanism, the polarization behavior of several metals in ferric chloride etchant has been investigated using DC polarization. Linear potential sweeps were applied to working electrodes of several metals, having an area of 1cm2, in ferric chloride etchants under static condition. Cyclic voltammograms at different scan rates indicated that the mass transfer processes control the reduction kinetics of ferric ions in the etchant. The steady state polarization curves indicated that the etching reaction was cathodic diffusion controlled. Kinetic parameters-diffusion coefficent, diffusion layer thickness and limiting cathodic currentwere determined by these electrochemical techniques. Since the corrosion current for metal dissolution must be balanced with the limiting cathodic current of ferric ions, the metals were shown to be dissolved at the same corrosion current in the same etchant as long as the above dissolution mechanism was occurred. The fundamental behavior of metal etching was successfully explained in terms of electrochemical reaction processes.
