Tadahiko Ogawa

Magnetic field effects on the electrodeposition of copper from copper sulphate in sulphuric acid

Abstract The crystal orientations of electrodeposited copper films were determined by X-ray diffraction analysis and scanning electron microscopy. Polarization curves were determined. Magnetic field effects had little or no effect on the texture coefficients. Current efficiency increased by 2% to 5% compared with that in the absence of a magnetic field; polarizations were smaller. The magnetic field had no effect on the direction of the lines of magnetic force, which depended on the magnetic flux densities. Anodic dissolution in a magnetic field proceeded uniformly and was considerably affected compared with electrodeposition.

The effect of lorentz force on copper electrodeposition from copper-EDTA baths.

The influence of magnetic fields on the structure of electrodeposits from complex, and on the mechanism of cathodic and anodic reactions with the electrodeposits were examined. Magnetic fluxdensity was 0.3T on the working electrode. It became clear that the action of Lorentz force accounted for the major part of magnetic field effect. The pH 12 electrolytic baths used were composed of 0.05-0.5mol·dm-3 CuSO4+0.1-1.0mol·dm-3 EDTA solutions including 0.2mol·dm-3 sodium sulfite. Anodic reactions were independent of magnetic field, but cathodic reactions were affected. The most important of these influences were as follows: The stability constant of the Cu(II)-EDTA complex became larger. Limiting current density increased. The (111) face of the deposits increased. The grain of the deposits was fine. Exchange current density decreased. Charge transfer resistance decreased. The temperature in the vicinity of the cathode dropped and that in vicinity of the anode rose. This was attributed to decrease in the thickness of the diffusion layer due to Lorentz force.