Monitoring of Electrolytic Degreasing by Impedance Measurements

Abstract

The change in the degree of surface degreasing with electrolytic degreasing time was investigated by an electrochemical method. Interfacial impedance was measured during electrolytic degreasing with cathode current, and/or after electrolytic degreasing for a certain period. The cathode current was set at 5mA to allow slow monitoring of the degreasing process. The analysis was conducted in terms of values of θ, which is an index of the surface reaction uniformity, double layer capacitance, C_dl, and the reaction resistance, R_p. During electrolytic degreasing, the value of θ decreased and that of C_dl increased with decreasing time. The values of θ and C_dl were constant after electrolytic degreasing was completed. After electrolytic degreasing for a certain period, θ and R_p decreased and C_dl increased.
It is suggested that the degree of electrolytic degreasing can be determined by monitoring impedance.