Barium titanate base ceramic composition having a high dielectric constant

Abstract

A ceramic composition having a high dielectric constant which has good stability with temperature variation and the passage of time includes BaTiO 3 in which the molecular ratio of Ba to Ti ranges from about 0.9 to 1.1 as the basic constituent and about 0.1 to 10 mol % of at least one compound selected from the group of Nb 2 O 5 and Ta 2 O 5 and about 0.01 to 15 mol % of at least one compound selected from the group consisting of In 2 O 3 , Ga 2 O 3 , Tl 2 O 3 , MgO, ZnO and NiO as sub constituents.

We claim: 
     
       1. A dielectric ceramic composition having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3  0.1 to 10 mol % of at least one of Nb 2  O 5  and Ta 2  O 5 , and about 0.01 to 15 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3 , and Tl 2  O 3 . 
     
     
       2. A dielectric ceramic composition having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3 , 0.1 to 10 mol % of at least one of Nb 2  O 5  and Ta 2  O 5 , about 0.01 to 15 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3 , and Tl 2  O 3 , and about 0.01 to 10 mol % of Al 2  O 3 . 
     
     
       3. A dielectric ceramic composition, having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3  as a basic constituent, 0.5 to 5.0 mol % of Nb 2  O 5  as a sub constituent, and 0.05 to 5.0 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3 , and Tl 2  O 3  as another sub constituent. 
     
     
       4. A dielectric ceramic composition, having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3  as a basic constituent, 0.5 to 5.0 mol % of Nb 2  O 5  as one sub constituent, 0.05 to 5.0 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3 , and Tl 2  O 3  as a second sub constituent and 0.5 to 5.0 mol % of Al 2  O 3  as a third sub constituent, the total amount of said sub constituents being within a range of 1.05 to 10 mol %. 
     
     
       5. A dielectric ceramic composition, having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3  as a basic constituent, 0.5 to 5.0 mol % of Ta 2  O 5  as a sub constituent, and 0.05 to 5.0 mol % of at least one of the compounds In 2  O 5 , Ga 2  O 3 , and Tl 2  O 3  as another sub constituent. 
     
     
       6. A dielectric ceramic composition, having a high dielectric constant, consisting of 77.5 to 99.79 mol % of BaTiO 3  as a basic constituent, 0.5 to 5.0 mol % of Ta 2  O 5  as a sub constituent, 0.05 to 5.0 mol % of at least one of the compounds In 2  O 5 , Ga 2  O 3 , and Tl 2  O 3  as another sub constituent and 0.5 to 5.0 mol % of Al 2  O 3  as a further sub constituent. 
     
     
       7. A dielectric ceramic composition, having a high dielectric constant, consisting of 77.5 to 99.79 mol % of non-stoichometric BaTiO 3  in which the molecular ratio of Ba to Ti lies within the range of approximately 0.9 to 1.1, 0.1 to 10 mol % of at least one of Nb 2  O 5  and Ta 2  O 5  ; and 0.01 to 15 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3  and Tl 2  O 3 . 
     
     
       8. A dielectric ceramic composition having a high dielectric constant, consisting of 77.5 to 99.79 mol % of non-stoichometric BaTiO 3  in which the molecular ratio of Ba to Ti lies within the range of approximately 0.9 to 1.1, 0.1 to 10 mol % of at least one of Nb 2  O 5  and Ta 2  O 5  ; 0.01 to 15 mol % of at least one of the compounds In 2  O 3 , Ga 2  O 3  and Tl 2  O 3  ; and further including 0.01 to 10 mol % of Al 2  O 3 .