Composition controlling of Co-Ni and Fe-Co alloys using pulse-reverse electroplating through means of experimental strategies

The optimal plating settings in the pulse-reverse electroplating mode for the non-anomalous plating of Co-Ni deposits (i.e., the metal composition of deposits is equal to that of the plating solutions) from chloride solutions were approached by using experimental strategies including fractional factorial design (FFD), path of steepest ascent and central composite design (CCD) coupled with the response surface methodology (RSM). The potentials and time period of pulse-plating were the key factors affecting the composition of Co-Ni deposits in the FFD study. The two variables were the path of the steepest ascent investigation to approach the optimal conditions for non-anomalous plating of Co-Ni deposits. The effects of pulse-plating potential and pulse-plating time on the compositions of Co-Ni deposits were further examined using a regression model in the CCD study. The variable Ni contents of Co-Ni deposits are caused by metal hydroxide on the deposit surface. After anodic dissolution process, the increasing pulse-plating time and lower pulse-plating potential can remove metal hydroxide and improve Ni ion deposition ratio on the fresh deposit. All Fe-Co deposits were equal to the composition metal ratio of plating bath while pulse-reverse-plating potential included the anodic dissolution process. (C) 2004 Elsevier Ltd. All rights reserved.