YAG glass-ceramic with a designed composition of 24Y2O3∙AG g2O3∙AG gl2 was prepared by a method which combines combustion synthesis with centrifugation. High temperature glass melt was produced from a highly-exothermic combustion reaction in Al/CuO system. Centrifugation induced high gravity field facilitates the crystallization of YAG from the glass melt. The effects of high gravity field on phase formation, composition distribution and morphology evolution of prepared YAG glass-ceramic were investigated. Morphology of YAG crystals changed gradually from dendritic to polygonal, and finally to columnar shape along high gravity direction. The density increased from 3.49 to 4.12 g cm−3, and the hardness increased from 7.8 to 9.7 GPa along high gravity direction. Ceramics International, 2014 A schematic illustration of the reaction chamber for combustion synthesis under high gravity field. The temperature profile of combustion reaction measured under normal gravity (1 g). The inset is a photograph of the prepared sample with a diameter of 40 mm. SEM micrographs of the sample prepared at 1000 g along high gravity direction: (a) interface layer between glass and glass-ceramic; (b) single large YAG dendrite; (c) small YAG dendrites; (d) transition layer between YAG dendrites and polygons; (e) YAG polygons layer; (f) YAG columnar crystals layer. SEM micrographs of the sample prepared at 1000 g along high gravity direction: (a) Al2O3 dendrites in the interface layer; (b) Al2O3 dendrite among YAG dendrites; (c) plate-like Al2O3 in the YAG dendrites layer; (d) plate-like Al2O3 in the transition layer between YAG dendrites and polygons.
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