Modified perovskite type composite oxide, method for preparing the same, and composite dielectric material

Abstract

The invention provides a modified perovskite type composite oxide in which the particle surface of a perovskite type composite oxide is coated with a first component of at least one selected from TiO 2 and SiO 2 and a second component of at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm, wherein the coating is formed by hydrolyzing at least one selected from a hydrolyzable TiO 2 precursor and a hydrolyzable SiO 2 precursor as a source of the first component and a salt of at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm as a source of the second component, and then calcining them.

1 . A modified perovskite type composite oxide in which a particle surface of a perovskite type composite oxide is coated with a first component of at least one selected from TiO 2  and SiO 2 , and a second component of at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm,
 wherein a coating is formed by hydrolyzing at least one selected from a hydrolyzable TiO 2  precursor and a hydrolyzable SiO 2  precursor as a source of the first component and a salt of at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm as a source of the second component, and then calcining them.   
     
     
         2 . The modified perovskite type composite oxide as set forth in  claim 1 , wherein the first component is TiO 2  and the second component is at least one selected from a group consisting of Nd, La, Ce, Pr, and Sm. 
     
     
         3 . The modified perovskite type composite oxide as set forth in  claim 1 , wherein the first component is SiO 2  and the second component is at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm. 
     
     
         4 . The modified perovskite type composite oxide as set forth in  claim 1 , wherein the coating is at a ratio of 0.05% by mass to 20% by mass in terms of oxides with respect to the perovskite type composite oxide. 
     
     
         5 . The modified perovskite type composite oxide as set forth in  claim 1 , wherein the perovskite type composite oxide is of an ABO 3  type, an A-site element is at least one selected from a group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at least one selected from Ti and Zr. 
     
     
         6 . The modified perovskite type composite oxide as set forth in  claim 1 , wherein a BET specific surface area of the perovskite type composite oxide is 0.5 m 2 /g to 12 m 2 /g. 
     
     
         7 . A method for preparing the modified perovskite type composite oxide, comprising:
 (A1) a step of dispersing perovskite type composite oxide particles in a solvent to prepare a slurry;   (A2) a step of adding a source of a first component of at least one selected from a hydrolyzable TiO 2  precursor and a hydrolyzable SiO 2  precursor and a salt of a source of a second component of at least one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm to the slurry obtained in (A1), carrying out a hydrolysis reaction of the precursor(s) and the salt in the presence of a catalyst, and then drying the slurry; and   (A3) a step of calcining the dried product obtained in (A2).   
     
     
         8 . The method for preparing the modified perovskite type composite oxide as set forth in  claim 7 , wherein the solvent is a hydrophilic organic solvent and the catalyst is an organic alkali. 
     
     
         9 . A composite dielectric material comprising the modified perovskite type composite oxide as set forth in  claim 1  and a polymer material. 
     
     
         10 . The modified perovskite type composite oxide as set forth in  claim 2 , wherein the coating is at a ratio of 0.05% by mass to 20% by mass in terms of oxides with respect to the perovskite type composite oxide. 
     
     
         11 . The modified perovskite type composite oxide as set forth in  claim 3 , wherein the coating is at a ratio of 0.05% by mass to 20% by mass in terms of oxides with respect to the perovskite type composite oxide. 
     
     
         12 . The modified perovskite type composite oxide as set forth in  claim 2 , wherein the perovskite type composite oxide is of an ABO 3  type, an A-site element is at least one selected from a group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at least one selected from Ti and Zr. 
     
     
         13 . The modified perovskite type composite oxide as set forth in  claim 3 , wherein the perovskite type composite oxide is of an ABO 3  type, an A-site element is at least one selected from a group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at least one selected from Ti and Zr. 
     
     
         14 . The modified perovskite type composite oxide as set forth in  claim 4 , wherein the perovskite type composite oxide is of an ABO 3  type, an A-site element is at least one selected from a group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at least one selected from Ti and Zr. 
     
     
         15 . The modified perovskite type composite oxide as set forth in  claim 2 , wherein a BET specific surface area of the perovskite type composite oxide is 0.5 m 2 /g to 12 m 2 /g. 
     
     
         16 . The modified perovskite type composite oxide as set forth in  claim 3 , wherein a BET specific surface area of the perovskite type composite oxide is 0.5 m 2 /g to 12 m 2 /g. 
     
     
         17 . The modified perovskite type composite oxide as set forth in  claim 4 , wherein a BET specific surface area of the perovskite type composite oxide is 0.5 m 2 /g to 12 m 2 /g. 
     
     
         18 . A composite dielectric material comprising the modified perovskite type composite oxide as set forth in  claim 2  and a polymer material. 
     
     
         19 . A composite dielectric material comprising the modified perovskite type composite oxide as set forth in  claim 3  and a polymer material. 
     
     
         20 . A composite dielectric material comprising the modified perovskite type composite oxide as set forth in  claim 4  and a polymer material.