| 摘要 |
PURPOSE: To extend the practically usable compositional range of a porcelain composition high in dielectric constant near ordinary temp., and in particular to make the porcelain composition in an industrially inexpensive compositional region practicable by adding calcium titanate into a specific three-component system solid solution. CONSTITUTION: In the production of this composition, lead oxide, nickel niobate, magnesium niobate, titanium niobate, calcium carbonate and calcium titanate, each of which has a >=99.9% purity are weighed out so as to obtain later a composition consisting of 10 to 30% Pb(Mg1/3 Nb2/3 )O3 , 45 to 60% Pb(Ni1/3 Nb2/3 )O3 , 19 to 30% PbTiO3 and 0 to 6% CaTiO3 . The raw materials thus weighed out are subjected to wet mixing in a ball mill and thereafter, the resultant solid mixture is separated by filtration and dried and calcined at 800 to 850 deg.C. Subsequently, the resultant powder is subjected to wet pulverization and the pulverized powder is separated by filtration and dried an, thereafter, mixed with polyvinyl alcohol aq. solution used as a binder and the mixture is granulated into granules, and then, the granules are press-formed into a formed body with a mold. The formed body is sintered at 950 to 1050 deg.C to obtain the objective composition which is formed by adding <=12mol% calcium titanate to a three-component system solid solution represented by the formula [Pb(Mg1/3 Nb2/3 ) O3 ]x [Pb(Ni1/3 Nb2/3 )O3 ]y [PbTiO3 ]z , wherein x+y+z=1. |
