Double layer mechanism in self­organization of copper secondary nodules under a parallel magnetic field

R. Aogaki¹ - R. Morimoto² - A. Sugiyama³ - M. Asanuma⁴

¹ Polytechnic University, 4­1­1, Hashoimotodai, Sagamihara-shi, Kanagawa, 229­1196, Japan }
² Saitama Industrial Technology Center, 3­12­18, Kamiaoki, Kawaguchi­shi, Saitama, 333­0844, Japan }
³ Waseda Institute for Advanced Study, 1­6­1, Nishi Waseda, Shinjuku­ku, Tokyo, 169­8050, Japan }
⁴ Yokohama Harbor Polytechnic College, 1 Honmokuhuto, Naka­ku, Yokohama, Kanagawa 231­0811, Japan

Abstract
From the long­term response of electrolytic current of copper deposition in a parallel magnetic ffeld, a new type of micro­MHD effect on the secondary nodules arising from the unstable growth of nonequilibrium ffuctuations in the electrical double layer (second micro­MHD effect) was theoretically analyzed. Such instability emerges with charac­ teristic convection cells (micro­MHD ffows). Then, the unstable condition that double layer overpotential must be positive was derived, which was ascertained by the copper deposition with proton adsorption at the double layer, leading to secondary nodules with ca. 100 µm diameter. To validate the theoretical results, the surface morphology of the deposit and the velocity distribution of the convection cells were theoretically calculated. Tables 1, Figs 8, Refs 6