Effects of Vertical Magnetohydrodynamic Flows on Chiral Surface Formation in Magnetoelectrolysis

Abstract

Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce chiral surfaces. This paper shows the effects of vertical MHD flow on the chiral surface formation in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. To control the vertical MHD flows the working electrode was embedded in a tube wall with various heights of 2–12 mm, and the vertical MHD flows were expected to penetrate into the tubes with damping. In both MED and MEE experiments, the surface chirality diminished considerably at the wall height of 12 mm. When the penetrating MHD flow could not reach the electrode surface in the sufficiently tall wall, such an MHD flow could not affect the micro-MHD vortices. These results demonstrate that the vertical MHD flow plays a significant role in symmetry breaking of micro-MHD vortices.