| 摘要 |
A method of synthesizing negative-thermal-expansion ceramics of synthesizing Zr(1-x)XxW2O8 in which X represents a substituent element for zirconium Zr, and 0<=x <<1, having a negative thermal expansion coefficient, the method comprising mixing two mols of tungsten trioxide WO3 and one mol of the sum of zirconium oxide ZrO2 and a substituent element X in accordance with substitution amount x at a stoichiometrical ratio, further mixing the thus obtained starting material in a powdery form having a particle size distribution including two groups of particles comprising smaller diameter particles with a particle size of 0.1 to 1 mum and larger diameter particles with a particle size of 5 to 50 mum, and then sintering the staring powder being placed in a desired molding die whereby negative-thermal-expansion ceramics having an increased density equal with or higher than that of press molding products and of a larger size than that of the press molding products without press-molding the starting powder can be synthesized.
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