Abstract: A study has been made of the cathodic polarization curves during the pulse plating of chromium from an aqueous chromic acid bath containing 250 g/L CrO₃ and 2.5 g/L H₂SO₄ at 22℃ over the range of pulse periods from 1 ms to 50 ms.The duty cycle was kept at 50%.The methods of potentiostatic pulse potential control and galvanostatic pulse current control were used to determine the polarization curves of a platinum and a copper rotating disk electrode in the chromium plating solution.The results indicated that pulse potential and pulse current inhibited the formation of a cathode film and shifted the potential of the hydrogen evolution reaction toward the positive direction by about 500 mV.The potential and current pulses behaved as a depolarter of H⁺ reduction reaction.The present results agreed with a previous experimental observation that the coulombic efficiency of the chromium deposition reaction was reduced and the coulombic efficiency of the hydorgen evolution reaction was increased in pulse plating of chromium.

Key words: Pulse, Plating, Chromium