Correlation between the Anti-cratering of Surface-treated Steels and the Change of Electric Currents during the Electrodeposition Coating

Abstract

The effect of the electric current density during the electrodeposition coating on the anti-cratering of surface-treated steels was studied.
1) The electric current density during the electrodeposition coating varied with the time in the slow-start method and many current density peaks were observed. The first peak current density was named as i_A, the final peak i_B.
2) The i_B/i_A varied discontinuously with the applied voltage and the voltage, at which the i_B/i_A increases discontinuously, was named the critical voltage.
3) It was found that the critical voltage was correlated with the tendency for the cratering of surface-treated steels and the steel having the high critical voltage showed the good anti-cratering properties.