DIELECTRIC CERAMIC COMPOSITION AND ELECTRONIC COMPONENT
The disclosed is a dielectric ceramic composition in which dielectric particles 2 a are formed. The dielectric particle 2 a has a core 22 a comprised of hexagonal barium titanate, and a shell 24 a formed on an outer circumference of the core 22 a and comprised of cubical or tetragonal barium titanate. The purpose of the present invention is to provide a new dielectric ceramic composition, in which permittivity is hardly lowered due to size effect, a good balance between high insulation resistance and permittivity can easily be achieved, and changes in insulation resistance and specific permittivity due to temperature are small; and an electronic component such as a multilayer ceramic capacitor using the dielectric ceramic composition as its dielectric layer.
1 . A dielectric ceramic composition in which dielectric particles are formed,
said dielectric particles comprising
a core comprised of hexagonal barium titanate,
a shell formed on an outer circumference of said core and comprised of cubical or tetragonal barium titanate.
2 . The dielectric ceramic composition as set forth in claim 1 , wherein
said hexagonal barium titanate is expressed by a general formula, (Ba 1-α M1 α ) A (Ti 1-β M2 β ) B O 3 ;
an effective ionic radius of said M1 is −20% or more to +20% or less with respect to an effective ionic radius of 12-coordinated Ba 2+ ;
an effective ionic radius of said M2 is −20% or more to +20% or less with respect to an effective ionic radius of 6-coordinated Ti 4+ ; and
said A, B, α and β satisfy the following relations: 0.900≦(A/B)≦1.040, 0≦α≦0.10 and 0≦β≦0.2.
3 . The dielectric ceramic composition as set forth in claim 2 , wherein
said cubical or tetragonal barium titanate is different in crystal structure from said hexagonal barium titanate but is expressed by said general formula, (Ba 1-α M1 α ) A (Ti 1-β M2 β ) B O 3 .
4 . The dielectric ceramic composition as set forth in claim 1 , wherein
a grain boundary is formed between said dielectric particles, and additive elements are dispersed in said grain boundary and/or said shell.
5 . The dielectric ceramic composition as set forth in claim 2 , wherein
a grain boundary is formed between said dielectric particles, and additive elements are dispersed in said grain boundary and/or said shell.
6 . The dielectric ceramic composition as set forth in claim 3 , wherein
a grain boundary is formed between said dielectric particles, and additive elements are dispersed in said grain boundary and/or said shell.
7 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 1 .
8 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 2 .
9 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 3 .
10 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 4 .
11 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 5 .
12 . An electronic component having a dielectric layer, wherein
said dielectric layer is comprised of the dielectric ceramic composition as set forth in claim 6 .