Fabrication of Ceramics Nano-Composites by Casting of Eutectic Melts in Multi-Component Systems

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[I]Major Establishments(1)The preparation of transparent bulk ceramics by melting/casting of eutectic melt in the ternary system Al_2O_3-HfO_2-GdAlO_3, and fabrication of ternary nano-composite ceramics by appropriate annealing of them (Papers 1 & 3).(2) The preparation of transparent bulk materials from the eutectic melt in pseudo-binary C_<12>A_7-CoYAlO_4 system in the ternary system Al_2O_3-CaO-Y_2O_3, and the fabrication of binary nano-composites by appropriate annealing of them (Papers 2,4 & 11).(3)The computer simulation can depict the solidification of the melts in these systems, thus explains their Nano-/Meso-/Micro-structures (Papers 5-8).(4)Those amorphous matrices and/or the ternary compound CaLaGaO_4 can be formed as a red phosphor by doping Eu (Papers 3,9 & 10).[II]Their ImportanceCeramics nano-composites have generally been fabricated from mixed powders by solid state processes : (1) Synthesis of them by solid state reactions, (2) the dispersion of powders, (3) molding of powders, (4) firing for sintering. Those processes are difficult to prepare homogeneous products and nano-structure controlled ones, because higher temperature firing would bring about the grain growth of every phase.The present research, on the other hand, (1) makes the homogeneous eutectic melts, (2) casts in a mold with the desired shape to fabricate the amorphous bulk, then (3) anneals to result in the nano-structures materials. Therefore, transparent nano-structured composites, which were very difficult to fabricate from powders by sintering, can be produced.Moreover, the solid solution samples with multi-components with homogeneous compositions can be produced by this method easily. The present method using melt/cast of eutectic melts, therefore, could be evaluated an innovative method for nano-composites ceramics. It was awarded as one of the best poster award (Paper #3) and the cover page of an International Journal (Paper #1).