抄録
The potential change of corroding systems responding to the repetitive square wave current was deduced theoretically. The corroding systems were simulated by a linear circuit which was constructed with polarization resistance, solution resistance and capacitance due to electrical double layer. The potential change, where the response reached a steady state, was obtained as
δΔEm=I0[(R+Rs)M(t, 2p)-(2R(-1)nexp{(n+1)p-t/CR})/(exp(p/CR)+1)]
where I0 is the amplitude of applied square wave current, Rs, solution resistance, R polarization resistance, M unit square wave function, t time, p period of square wave, and n the maximum integer which does not exceed t/p. From this equation several ways of separating R, Rs, and C, from each other were proposed being based upon the following relations.
δΔEm(t=np)=2I0Rs, ΔEp(p→∞)=ΔEp(f→0)=2I0(R+Rs)
ΔEp(f→∞)=2Rs, {∂ΔEp/∂(1/f)}(1/f→0)=2I0/C
where δΔEm(t=np) is potential change at the instant of polarity change and ΔEp is the peak-to-peak value of potential change. Finally, the feature of this method was discussed.
