Morphology of Reduction-Grown Metal Microcrystals

Kiyoshi Kishi¹, Sei-ichi Kurishiro¹, Ken-ichi Koike¹, Arata Yoshida¹, Teruto Yoshida¹, Kenji Yoshioka¹, Hisami Yumoto² and Kuniharu Takizawa³

¹Department of Applied Physics, Science University of Tokyo, Kagurazaka, Sinjuku-ku, Tokyo 162, Japan
²Department of Materials Science and Technology, Science University of Tokyo, Noda, Chiba 277, Japan
³NHK Science and Technical Research Laboratories, Kinuta, Setagaya-ku, Tokyo 157, Japan

(Received April 11, 1994; Accepted July 11, 1994)

Keywords: Dendrites, Whiskers, Crystal Growth, Complex Diffusion Field, Pattern Formation

Abstract. Microcrystals of Cu form many striking artistic patterns, which is comparable with snow flakes. The structure of microcrystals is fcc, which is one of the most simple structure, nevertheless, with the aid of both unidirectional growth and twinning, they do the impossible. The microcrystals are whiskers and dendrites grown from CuX by Zn reduction. The whiskers are essentially single crystals, but the dendrites are single crystals and both simple and multiply twin crystals. Both two-dimensional and three-dimensional artistic patterns grow apparently showing two, three, four, and fivefold and spiral symmetries.