Papers by Author: Atsushi Chiba

Abstract: SUS 304 used. A passive film on surface was needed to remove with anodic electrolytic degreasing in 3.0 mol/dm3 H2SO4 at 298 K. Cu film was electroplated 20 mA/cm2 in 0.5 mol/dm3 CuSO4 and 2 mol /dm3 H2SO4. Current efficiency increased when plating carried in sonication of 28 kHz after plating in stationary state. Particles were destroyed and size became smaller with shockwave pressure. Particles were pressed in pinholes, defects, etc. Surface that was obtained at 28 kHz was smooth and dense compared with other agitation states.

Abstract: Zn plated on Cu plate from 0.65 mol/dm3 alkali zincate solution in 8 mol/dm3 KOH bath Electrolysis was carried out as current density of 10 - 100 mA/cm2. The sonication was prepared 40 kHz. The current efficiency was 76.1 % at 10 mA/cm2 in 0.10 mol/dm3 zincate and 100 % in 0.15 mol/dm3 zincate at 50 mA/cm2. The current efficiency and thickness of diffusion layer affected with the agitation of micro-jet. Surface of film was smooth and dense as particle crushed down with the shockwave pressure. (112) plane moved horizontally to <113> direction under the compressive stress or shearing stress.

Abstract: This study concerns the development of Pb free solder plating due to environmental concerns. The composition of the bath was 0.1 mol/dm3 SnY and 0.1 mol/dm3 BiY- in 2 mol/dm3 CH3COOH - 2 mol/dm3 CH3COONa buffer solution (pH 4.0). The bath used 100 cm3 of solution. Plating was carried out at a current density of 50 mA/cm2 using ultrasonic agitation (sonication) at 28 kHz (100 W). Various percentages of a Sn - Bi alloy could be plated. A 41wt.%Sn - 59 wt.%Bi alloy with a melting point of 415 K was obtained from a [BiY-]/[BiY-+SnY] = 0.3 bath. The surface morphologies of the plated films showed a striking difference in accordance with a change of composition.