Control of Periodicity and Growth Rate of Oscillatory Zoning in Particle by Chemical Process

Abstract

Oscillatory zoning is a kind of spontaneous pattern of micrometer scale formed in a particle. Many studies have been performed in the field of geoscience for which several weeks were required for pattern formation. In this study, a drastic reduction of the pattern forming period has been realized such that the pattern forming dynamics may be applied to particle processing technology. The repetition of ion supply and the subsequent ripening enable the formation of a pattern in less than a few hours. The chemical composition in the cross section of a particle varied in an oscillatory manner with the spatial period of 10² nm–10¹ µm. This fine chemical structure was generated spontaneously without hazardous chemicals such as organic solvents and surfactants. The spatial periodicity and the compositional amplitude are controlled by the periods of the ion supply and the subsequent ripening, respectively.