Perovskite titanium-containing composite oxide particle, production process and uses thereof

• US 20060078492A1
• Filed: 10/11/2005
• Published: 04/13/2006
• Est. Priority Date: 04/11/2003
• Status: Abandoned Application

• Current Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.)
• Inventors: Kurozumi, Tadatoshi, Shirakawa, Akihiko, Yokouchi, Hitoshi
• Application Number:
  US11/246,373
• Publication Number:
  US 20060078492A1
• Time in Patent Office: Days
• US Class Current: 423/598
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/003 Titanates C01G23/001 takes precedence
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/11 with a prismatic shape
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/13 thermal stability thereof at high temperatures
• CPC Class Codes: C04B 2235/02 Composition of constituents of the starting material or of secondary phases of the final product
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3234 Titanates, not containing zirconia
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/3296 Lead oxides, plumbates or oxide forming salts thereof, e.g. silver plumbate
• CPC Class Codes: C04B 2235/52 Constituents or additives characterised by their shapes
• CPC Class Codes: C04B 2235/5204 Monocrystalline powders
• CPC Class Codes: C04B 2235/528 : Spheres
• CPC Class Codes: C04B 2235/5409 : expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 : micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 : submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5454 : nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/5481 : Monomodal
• CPC Class Codes: C04B 2235/549 : the particle size being expressed by crystallite size or primary particle size
• CPC Class Codes: C04B 2235/72 : Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/724 : Halogenide content
• CPC Class Codes: C04B 2235/762 : Cubic symmetry, e.g. beta-SiC
• CPC Class Codes: C04B 2235/768 : Perovskite structure ABO3
• CPC Class Codes: C04B 35/465 : based on alkaline earth metal titanates
• CPC Class Codes: C04B 35/4682 : based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/47 : based on strontium titanates
• CPC Class Codes: C04B 35/472 : based on lead titanates
• CPC Class Codes: C04B 35/62645 : Thermal treatment of powders or mixtures thereof other than sintering
• CPC Class Codes: H01B 3/12 : ceramics
• CPC Class Codes: H01G 4/1227 : based on alkaline earth titanates

Abstract

The present invention provides a perovskite titanium-containing composite oxide fine particle represented by the formula: (A1_XA2_(1−X))_YTiO_3±δ (wherein 0≦X≦1, 0.98≦Y≦1.02, 0≦δ≦0.05, A1 and A2 each is an atom selected from a group consisting of Ca, Sr, Ba, Pb and Mg and are different from each other), wherein the specific surface area is from 1 to 100 m²/g and the D2/D1 value is from 1 to 10.

Claims

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

(A1_XA2<sub>(1−

X)</sub>)_YTiO<sub>3±

δ</sub>

(wherein 0≦

X≦

1, 0.98≦

Y≦

1.02, 0≦

δ

≦

0.05, A1 and A2 each is an atom selected from a group consisting of Ca, Sr, Ba, Pb and Mg and are different from each other), wherein the specific surface area is from 1 to 100 m²/g and the D2/D1 value is from 1 to 10, wherein D1 represents average primary particle size and D2 represents the average particle size of secondary particles.

2. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, which has a single crystal of perovskite titanium-containing composite oxide.

3. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1 or 2, comprising a tetragonal prism shape or a shape analogous to tetragonal prism.

4. The perovskite titanium-containing composite oxide fine particle as claimed in claim 3, wherein the ratio of the long side to the short side of the crystal is from 1.1 to 6.

5. The perovskite titanium-containing composite oxide fine particle as claimed in claim 3, wherein the long side of the crystal is extending to the unit cell (010) plane.

6. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the D2/D1 value is from 1 to 3.

7. The perovskite titanium-containing composite oxide fine particle as claimed claim 1, wherein D3/D2 value is from 0.1 to 0.9 and D3 represents the particle size of secondary particles at 10% from the minimum.

8. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein D4/D2 value is from 1.1 to 10 and D4 represents the particle size of secondary particles at 90% from the minimum.

9. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the compound represented by (A1_XA2₍₁₋

X))_YTiO<sub>3±

δ</sub>

is CaTiO₃ and the calcium carbonate content is 3 mass % or less.

10. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the specific surface area is from 1 to 10 m²/g.

11. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein calcining at any temperature of 900 to 1,200°

C., the decrease in the specific surface area is 8 m²/g or less.

12. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein 0.2≦

X≦

0.8, 0.99≦

Y≦

1.01, 0≦

δ

≦

0.03 and the fine particle is a single crystal.

13. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein A1 is Ba and A2 is Sr.

14. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the amount of alkali metal impurities is from 0 to 100 ppm and the amount of chlorine impurities is from 0 to 600 ppm.

15. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein calcining for 0.1 to 3 hours at any temperature from 900 to 1,000°

C., the percentage decrease in the specific surface area is 90% or less.

16. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the shape becomes a dice form after calcining for 0.1 to 3 hours at any temperature from 900 to 1,200°

C.

17. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein the amount of carbonate is 3 mass % or less.

18. The perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein when 1.5 g of the perovskite titanium-containing composite oxide particle is immersed in 45 ml of pure water, the total extraction amount of A1 atom and A2 atom per unit surface area is from 0 to 2 μ

mol/m².

19. A process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 1, wherein a titanium oxide sol and a metal salt are added into an alkaline aqueous solution comprising basic compound, and then react.

20. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the metal salt is added in a weight of 10 to 10,000 times by mass the saturated solubility in an alkaline solution.

21. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the calcium salt is a hydroxide.

22. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, comprising controlling the concentration of a carbonic acid group in the reaction solution to 500 ppm or less in terms of CO₂.

23. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, comprising a step of boiling the reaction system at 100°

C. or more for 2 hours or more.

24. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, which comprises a step of removing impurities as gas by evaporation and/or thermal decomposition under atmospheric or reduced pressure in the temperature range from room temperature to calcining temperature.

25. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the titanium oxide sol is obtained by hydrolyzing titanium compounds in an acidic solution.

26. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the titanium oxide sol comprises a brookite crystal.

27. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the basic compound is a substance which becomes gas by evaporation, sublimation and/or thermal decomposition under atmospheric or reduced pressure.

28. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 27, wherein the basic compound is an organic base.

29. The process for producing the perovskite titanium-containing composite oxide fine particle as claimed in claim 19, wherein the basic compound is a tetramethylammonium hydroxide.

38. A dielectric material comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

39. A paste comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

40. A slurry comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

41. A thin-film material comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

42. A dielectric porcelain comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

43. A pyroelectric porcelain comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

44. A piezoelectric porcelain comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

45. A capacitor comprising the dielectric porcelain as claimed in claim 42.

46. An electronic device comprising the thin-film material claimed in claim 41.

47. A sensor comprising the thin-film material claimed in claim 41.

48. A dielectric film comprising the perovskite titanium-containing composite oxide fine particle as claimed in claim 1.

49. A capacitor comprising the dielectric film as claimed in claim 48.

50. An electronic device comprising the porcelain claimed in any one of claims 42 to 44.

51. An electronic device comprising the capacitor as claimed in claim 45.

52. A sensor comprising a porcelain as claimed in any one of claims 42 to 44.

30. A process for producing a perovskite titanium-containing composite oxide fine particle, comprising reacting A1(OH)₂ and A2(OH)₂ at an arbitrary ratio with titanium oxide of 0.98 to 1.02 mol times the total mol of A1(OH)₂ and A2(OH)₂ in an alkaline solution comprising a basic compound and having a pH of 10 or more, wherein A1 and A2 each represent an atom selected from a group consisting of Ca, Sr, Ba, Pb and Mg, continuing the reaction until the total concentration of A1 ion and A2 ion in the reaction solution becomes 1/1,000 or less of the amount added and after the completion of reaction, removing the basic compound as gas by evaporation, sublimation and/or thermal decomposition under atmospheric or reduced pressure in the temperature range from room temperature to calcining temperature.

31. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the molar ratio of A1(OH)₂ to A2(OH)₂ is from 0.2 to 0.8.

32. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, comprising controlling the concentration of a carbonic acid group in the reaction solution to a range from 0 to 500 ppm in terms of CO₂.

33. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the titanium oxide comprises a brookite crystal.

34. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the titanium oxide is obtained by hydrolyzing a titanium compound in an acidic solution.

35. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the basic compound is a substance which becomes gas by evaporation, sublimation and/or thermal decomposition under atmospheric or reduced pressure.

36. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the basic compound is an organic base.

37. The process for producing a perovskite titanium-containing composite oxide fine particle as claimed in claim 30, wherein the basic compound is a tetramethylammonium hydroxide.