In situ observation of inhomogeneous texture during melting and freezing of liquid gallium by projection-type X-ray diffraction imaging

Abstract

Gallium is known to exist as a liquid state in the widest temperature region among all elements, since its melting and boiling points are 29.76°C and 2205°C, respectively. So far, there have been a number of interesting work on the physical and chemical properties of its liquid state, because the research can be done at near room temperature. From a view point of applications, it is a highly efficient cooling material, which is a promising alternative to water. On the other hand, the structures of non-equalibrium state, i.e., the freezing and the melting process has not yet been well studied, mainly because of technical limitation in the experiments. For such observations, it is absolutely necessary to collect the X-ray diffraction pattern quickly without moving the sample. Moreover, since the sample usually becomes inhomogeneous, imaging of X-ray diffraction information is crucial. Projection-type X-ray diffraction imaging is a novel technique, which can give real-space image for the X-ray diffraction from an inhomogeneous polycrystalline sample. The present paper reports on some preliminary in situ observation of freezing and melting process of liquid gallium. © 2010 The Japan Society for Analytical Chemistry.