Titanium-containing perovskite composite oxide particle, production process thereof and capacitor

• US 20060133988A1
• Filed: 12/21/2005
• Published: 06/22/2006
• Est. Priority Date: 12/21/2004
• Status: Abandoned Application

• Current Assignee: Showa Denko KK
• Original Assignee: Showa Denko KK
• Inventors: Kurozumi, Tadatoshi, Yokouchi, Hitoshi
• Application Number:
  US11/312,460
• Publication Number:
  US 20060133988A1
• Time in Patent Office: Days
• US Class Current: 423/598
• CPC Class Codes: C01G 23/003 Titanates C01G23/001 takes precedence
• CPC Class Codes: C01G 25/006 Compounds containing, besides zirconium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 27/006 Compounds containing, besides hafnium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01G 4/1218 based on titanium oxides or titanates H01G4/1245 takes precedence
• CPC Class Codes: H01G 4/30 Stacked capacitors H01G4/33 takes precedence
• CPC Class Codes: H10N 15/15 Selection of materials
• CPC Class Codes: H10N 30/853 Ceramic compositions

Abstract

A titanium-containing perovskite composite oxide particle represented by the compositional formula: A(Ti_xB_(1−x))_yO₃ (provided that x and y each denoting a compositional ratio are 0≦x≦1 and 0.98≦y≦1.02, A is at least one or more element selected from Ca, Sr, Ba, Pb and Mg, and B is at least one or more element selected from Hf and Zr), wherein the specific surface area is from 1 to 100 m²/g, the average primary particle diameter D1 defined by formula (I) is from 10 to 1,000 nm, and the ratio D2/D1 of D1 to the average secondary particle diameter D2 is from 1 to 10:
D1=6/ρS  (I)(wherein ρ is a density of the particle and S is a specific surface area).

Claims

1. A titanium-containing perovskite composite oxide particle represented by the compositional formula:

A(Ti_xB<sub>(1−

x)</sub>)_yO₃ (provided that x and y each denoting a compositional ratio are 0<

x<

1 and 0.98≦

y≦

1.02, A is at least one or more element selected from Ca, Sr, Ba, Pb and Mg, and B is at least one or more element selected from Hf and Zr), wherein the specific surface area is from 1 to 100 m²/g, the average primary particle diameter D1 defined by formula (I) is from 10 to 1,000 nm, and the ratio D2/D1 of D1 to the average secondary particle diameter D2 is from 1 to 10;

D1=6/ρ

S 

 

(I)

(wherein ρ

is a density of the particle and S is a specific surface area).

2. The titanium-containing perovskite composite oxide particle as described in claim 1, wherein assuming that the average particle diameter on the volume basis as determined by an image analysis method is d1, the particle diameter at 5% accumulated from the small particle diameter side is d2, the particle diameter at 95% accumulated from the small particle diameter side is d3 and the maximum particle diameter is d4, d2/d1 is from 0.1 to 1, d3/d1 is from 1 to 1.8 and d4/d1 is from 1 to 2.

3. The titanium-containing perovskite composite oxide particle as described in claim 1 or 2, wherein the alkali metal content is 100 ppm or less and the chlorine content is 600 ppm or less.

4. The titanium-containing perovskite composite oxide particle as described in claim 1, wherein A is Ba, B is Zr, and x denoting the compositional ratio is 0.4≦

x<

1.

5. The titanium-containing perovskite composite oxide particle as described in claim 1, wherein A comprises Ba and Ca, B is Zr, and x denoting the compositional ratio is 0.4≦

x<

1.

6. The titanium-containing perovskite composite oxide particle as described in claim 1, wherein A is Pb, B is Zr, and x denoting the compositional ratio is 0.3≦

x≦

0.7.

7. A process for producing the titanium-containing perovskite composite oxide particle described in claim 1, comprising a step of charging a metal salt containing at least one member selected from Ca, Sr, Ba, Pb and Mg, a particulate titanium oxide and a compound containing at least one member selected from Zr and Hf, in a basic compound-containing alkaline solution and reacting these components.

8. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, which comprises a step of removing the basic compound in the form of a gas after the reaction step.

9. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein a heat treatment is performed at a temperature of 350 to 1,500°

C. after the step of removing the basic compound.

10. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the particulate titanium oxide contains a brookite crystal.

11. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the particulate titanium oxide is a titanium oxide sol obtained by hydrolyzing a titanium compound in an acidic solution.

12. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the basic compound is a substance which vaporizes under atmospheric pressure or reduced pressure by at least one or more means selected from evaporation, sublimation and thermal decomposition.

13. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the basic compound is an organic base compound.

14. The production process of a titanium-containing perovskite composite oxide particle as described claim 7, wherein the basic compound is tetramethyl-ammonium hydroxide.

15. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the Zr or Hf compound is a water-soluble compound.

16. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the solubility of the Zr or Hf compound in water is 0.1 mass % or more in terms of ZrO₂ or HfO₂.

17. The production process of a titanium-containing perovskite composite oxide particle as described in claim 7, wherein the Zr compound is one or more compound selected from basic zirconium carbonate, zirconium acetate, zirconium nitrate, ammonium zirconium carbonate, zirconium sulfate and zirconium hydroxychloride.

18. A dielectric material comprising the titanium-containing perovskite composite oxide particle described in claim 1.

19. A paste comprising the titanium-containing perovskite composite oxide particle described in claim 1.

20. A slurry comprising the titanium-containing perovskite composite oxide particle described in claim 1.

21. A thin film-shaped product comprising the titanium-containing perovskite composite oxide particle described in claim 1.

22. A dielectric porcelain comprising the titanium-containing perovskite composite oxide particle described in claim 1.

23. A pyroelectric porcelain comprising the titanium-containing perovskite composite oxide particle described in claim 1.

24. A piezoelectric porcelain comprising the titanium-containing perovskite composite oxide particle described in claim 1.

25. A capacitor comprising the dielectric porcelain described in claim 22.

26. An electronic device comprising the thin film-shaped product described in claim 21.

27. A sensor comprising the thin film-shaped product described in claim 21.

28. A dielectric film comprising the titanium-containing perovskite composite oxide particle described in claim 1.

29. A capacitor produced by using the dielectric film described in claim 28.