Relation between size and phase structure of gallium: Differential scanning calorimeter experiments

The relation between sizes and phase structures of gallium has been studied. Gallium droplets with different sizes dispersed in poly(methyl methacrylate) and silicone oil were studied by differential scanning calorimeter and transmission electron microscopy. The results showed that particles with different sizes corresponded to stable or metastable phases of gallium. The stable phase alpha-gallium is dominantly formed when the average size of particles is no less than 0.8 micron, and the metastable phases beta-, gamma- and delta-gallium are mainly formed when the average particle size is 0.8-0.6 micron, 0.6-0.3 micron, and below 0.3 micron, respectively. The phase selection in the solidification process under undercooling is used to explain the results.