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Measurement of the lifetime of ionic vacancy by the cyclotron-MHD electrode
R. Aogaki1 - K. Motomura1 - A. Sugiyama2 - R. Morimoto3 - I. Mogi4 - M. Miura5 - M. Asanuma6 - Y. Oshikiri7
1 Polytechnic University, 2-20-12-1304 Ryogoku, Sumida-ku, Tokyo 130-0026, Japan
2 Graduate School of Advanced Science and Engineering, Waseda University, 3-14-9 Okubo, Shinjuku-ku, Tokyo 169-0855, Japan
3 Saitama Prefectural Okubo Water Filtration Plant, 618 Shuku, Sakura-ku, Saitama-shi, Saitama 338-0814, Japan
4 Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai-shi, Miyagi 980-8577, Japan
5 Tohoku Polytechnic College, AKITA, 6-1 Ogita-Michishita, Odate-shi, Akita 017-0805, Japan
6 Yokohama Harbour Polytechnic College, 1 Honmokufuto, Naka-ku, Yokohama-shi, Kanagawa 231-0811, Japan
7 Yamagata College of Industry and Technology, 2-2-1 Matsuei, Yamagata-shi, Yamagata 990-2473, Japan
Abstract
With a new type of magnetohydrodynamic (MHD) electrode called cyclotron MHD electrode (CMHDE), the lifetime of ionic vacancy created in copper electrodeposition has been first measured. In a CMHDE, coaxial cylinders partly exposed as electrodes are placed vertically in an electrolytic solution under a vertical magnetic field, so that induced Lorentz force makes ionic vacancies circulate together with the solution along the circumferences. At low magnetic fields, ionic vacancies once created become extinct on the way of returning, whereas at high magnetic fields, they can come back to their initial birth points in enhanced velocities. By detecting the difference between these two states, we can measure the lifetime of ionic vacancy. At the same time, by changing the collision efficiency between created and returning vacancies, two reaction processes, i.e., the decay of ionic vacancy and the conversion to nanobubble can be analyzed. As a result, in the present case, it was concluded that the intrinsic lifetime of ionic vacancy is 8.6 s, and the formation time of nanobubble from the collision of ionic vacancies is 0.072 s. Figs 9, Refs 8.