| 摘要 |
PURPOSE:To obtain machinable dense ceramics hardly adsorbing and desorbing gas and easily undergoing fine machining and precision machining by subjecting fluorine phlogopite-glass-ceramics produced by sintering to hot isostatic pressing. CONSTITUTION:Kaolin and activated clay as principal starting materials are mixed with compds. contg. Mg and K as secondary starting materials and B2O3 as a sintering aid so as to give a sintered body consisting of, by weight, 35-60% SiO2, 10-20% Al2O3, 10-25% MgO, 3-15% K2O, 2-15% F and 1-3% B2O3 when expressed in terms of oxides. The resulting fine powdery mixture is calcined at 1,000-1,100 deg.C max. temp. to obtain a calcined body contg. 30-60vol.% fluorine phlogopite crystals. Fine particles of this calcined body are molded into a desired shape and sintered at 1,100-1,250 deg.C max. temp. This sintered body is subjected to hot isostatic pressing at 800-1,000 deg.C max. temp. under 500-2,000kg/cm<2> max. pressure to obtain machinable dense ceramics. |
