Method of producing porous shaped bodies, porous shaped bodies, porous sintered bodies, porous bodies of inorganic materials and composite members

• US 20060204764A1
• Filed: 03/13/2006
• Published: 09/14/2006
• Est. Priority Date: 11/28/2003
• Status: Abandoned Application

• Current Assignee: NGK Insulators Limited
• Original Assignee: Kazuki Nakanishi, Kazuyuki Hirao, NGK Insulators Limited
• Inventors: Nakanishi, Kazuki, Fujita, Koji, Sato, Yousuke, Hanzawa, Shigeru, Hirao, Kazuyuki
• Application Number:
  US11/375,603
• Publication Number:
  US 20060204764A1
• Time in Patent Office: Days
• US Class Current: 428/426
• CPC Class Codes: B01J 20/0211 Compounds of Ti, Zr, Hf
• CPC Class Codes: B01J 20/0244 Compounds of Zn
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/28085 being more than 50 nm, i.e. macropores
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 35/14 based on silica
• CPC Class Codes: C04B 35/453 based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
• CPC Class Codes: C04B 35/46 based on titanium oxides or titanates containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/624 Sol-gel processing
• CPC Class Codes: C04B 35/62655 Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/63 using additives specially adapted for forming the products , e.g.. binder binders
• CPC Class Codes: C04B 38/0045 by a process involving the formation of a sol or a gel, e.g. sol-gel or precipitation processes
• CPC Class Codes: C04B 38/0054 the pores being microsized or nanosized

Abstract

The aggregation and phase separation of inorganic particles are performed in a sol containing the inorganic particles and a solvent to produce a porous body having open pores. Preferably, the inorganic particles are particles of one or more inorganic material selected from the group consisting of titania, silica, alumina, zinc oxide and zirconia. Further, the sol may have strong acidity and the pH of the sol is elevated to perform the aggregation and phase separation of the inorganic particles. Alternatively, the sol may have strong basicity and the pH of the sol is lowered to perform the aggregation and phase separation of the inorganic particles. The present invention provides a novel method of producing a porous body and sintered body having co-continuous structure, applicable to a wide variety of inorganic materials.

Claims

1. A method of producing a porous body comprising open pores;

said method comprising the step of;

performing aggregation and phase separation of inorganic particles in a sol comprising said inorganic particles and a solvent.

2. The method of claim 1, wherein said inorganic particles comprises one or more inorganic material selected from the group consisting of titania, silica, alumina, zinc oxide and zirconia.

3. The method of claim 1, wherein said sol has a strong acidity and wherein the pH of said sol is elevated to perform said aggregation and phase separation.

4. The method of claim 1, wherein said sol has a strong basicity and wherein the pH of said sol is lowered to perform said aggregation and phase separation.

5. The method of claim 3, wherein said sol comprises a compound capable of releasing a substance changing the pH of said sol over time.

6. The method of claim 1, wherein said sol comprises a water soluble polymer or a surfactant.

7. The method of claim 1, wherein said solvent is removed by drying after said phase separation.

8. A porous body obtained by the method of claim 1.

9. A composite material comprising a holding member comprising a space formed therein and a porous body generated in said space, wherein said holding member comprises an inner wall surface facing said space, wherein said inner wall surface has a central average surface roughness Ra of 0.05 μ

m or more, and wherein said porous body comprises the porous body of claim 8.

10. The composite material of claim 9, wherein said space has a width of 1 mm or smaller.

11. A composite material of claim 9, wherein said holding member comprises a honeycomb structure.

12. A method of producing a porous sintered body comprising open pores;

said method comprising the steps of;

performing aggregation and phase separation of inorganic particles in a sol comprising said inorganic particles and a solvent to obtain a porous body, and

subjecting said porous body to a heat treatment.

13. The method of claim 12, wherein said inorganic particles comprises one or more inorganic material selected from the group consisting of titania, silica, alumina, zinc oxide and zirconia.

14. The method of claim 12, wherein said sol has a strong acidity and wherein the pH of said sol is elevated to perform said aggregation and phase separation.

15. The method of claim 12, wherein said sol has a strong basicity and wherein the pH of said sol is lowered to perform said aggregation and phase separation.

16. The method of claim 14, wherein said sol comprises a compound capable of releasing a substance changing the pH of said sol over time.

17. The method of claim 12, wherein said sol comprises a water soluble polymer or a surfactant.

18. The method of claim 12, wherein said solvent is removed by drying after said phase separation.

19. A porous body obtained by the method of claim 12.

20. A composite material comprising a holding member comprising a space formed therein and a porous sintered body generated in said space, wherein said holding member comprises an inner wall surface facing said space, wherein said inner wall surface has a central average surface roughness Ra of 0.05 μ

m or more, and wherein said porous sintered body comprises the porous sintered body of claim 19.

21. The composite material of claim 20, wherein said space has a width of 1 mm or smaller.

22. The composite material of claim 20, wherein said holding member comprises a honeycomb structure.

23. A porous body comprising one or more inorganic material selected from the group consisting of titania, silica, alumina, zinc oxide and zirconia, said porous body comprising macro pores having a pore size of 0.1 μ

m or more, wherein 50 percent or more of said macro pores having a pore size of 0.1 μ

m are distributed in a range of ±

20 percent with respect to the central pore size of said porous body.