| 摘要 |
PURPOSE:To provide a nonagglomerate of dense fine particles state which is amorphous but has no agglomerate continuous phase by a method wherein lead titanate for ceramic use is rendered amorphous and is caused to have an apparent particle size below a specific value and a crystallization temperature in a specific range. CONSTITUTION:This ceramic base material consists of an amorphous lead titanate whose molar ratio of PbO:TiO2 is in the range of 6:1-1:1 (particularly 4:1-1:1) in which the lead titanate is of fine particles having an apparent particle size less than 5 microns and a crystallization temperature in the range of 500-600 deg.C. The fine particles indicate the mercury-impregnation pore volume of 0.2ml/g or less (particulary 0.1ml/g or less) when they are vacuum-dehydrated from their aqueous slurry and measured as a formed body sintered at 600 deg.C or below. Said ceramic base material is obtained by reacting, in an aqueous medium, the above molar ratio of PbO:TiO2 by composing it from oxynitrate of titanium and lead monooxide having a density of 8.3-9.2g/cc, a secondary particle size of 0.2 microns or less, an infrared absorption peak in the range of wave number 1,400-1,410, and a 94% or more reaction ratio to anhydrous chromic acid. |
