Sono-electroplating of bismuth film from Bi(III)-EDTA bath

Abstract

BiOCH3COO and EDTA-4Na were dissolved in 2 mol/dm3 CH3COOH-2 mol/dm3 CH3COONa buffer solution, and was adjusted to pH4.1 by adding 2 mol/dm3 CH3COOH or 2 mol/dm3 CH3COONa. 100 cm3 of this electrolyte was used. Electroplated film was obtained in the range of 10-100 mA/cm 2. Sono-electroplating was carried out smoothly, because the mass transfer accelerated with ultrasonic agitation and Bi ion was supplied to electrode surface. The mass transfer and crystallization processes were most affected with micro-jet and shock wave pressure. Best conditions of sono-electroplating were 0.10 mol/dm3 BiY- , pH 4.0-5.5, 298 K and 10 mA/cm2. Exchange current density and reaction rate constant in the sonication increased compared with that in the stationary state. As for this, an electron reaction became fast by the micro-jet or a shock wave pressure. The plated film was smoothness and denseness in sonication compared with that in stationary state. It was concluded that main factor that the surface became smooth was shock wave pressure. © 2009 The Surface Science Society of Japan.