Aluminum-titanate-based ceramic honeycomb structure, its production method, and starting material powder for producing same
A ceramic honeycomb structure having a large number of flow paths partitioned by porous cell walls, the cell walls comprising at least main crystals of aluminum titanate, in which MgO and SiO 2 are dissolved to form a solid solution, and glass phases, the glass phases containing 40-80% by mass of SiO 2 and 1-20% by mass of MgO, the average size of the glass phases being 30 μm or less in a cross section of the cell walls, and the area ratio of the glass phases to the total area of the main crystals of aluminum titanate and the glass phases being 2-12% in a cross section of the cell walls, and its production method.
1. A method for producing an aluminum-titanate-based ceramic honeycomb structure, comprising the steps of mixing 100 parts by mass of a powder material comprising alumina powder containing 0.05-0.5% by mass of Na 2 O and titania powder containing 0.5% or less by mass of Na 2 O at a molar ratio of 47/53 to 53/47, with at least 1-6 parts by mass of silica powder and 0.5-5 parts by mass of magnesia source powder having an average particle size of 5 μm or less; molding the mixed powder material to a honeycomb structure; heating the resultant molding at an average speed of 10° C./hr to 100° C./hr in a temperature range of 1300° C. to 1350° C.; and sintering it at the highest keeping temperature of 1400-1650° C. to obtain an aluminum-titanate-based ceramic honeycomb structure comprising at least main crystals of aluminum titanate, in which MgO and SiO 2 are dissolved to form a solid solution, and glass phases.
2. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 1 , wherein said alumina powder has an average particle size of 0.1-10 μm, said titania powder has an average particle size of 0.05-3 μm, and said silica powder has an average particle size of 0.1-30 μm.
3. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 2 , wherein said alumina powder has an average particle size of 2-6 μm.
4. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 3 , wherein a pore-forming material is added to said mixed powder material.
5. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 3 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
6. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 4 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
7. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 2 , wherein a pore-forming material is added to said mixed powder material.
8. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 7 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
9. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 2 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
10. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 1 , wherein said alumina powder has an average particle size of 2-6 μm.
11. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 10 , wherein a pore-forming material is added to said mixed powder material.
12. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 11 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
13. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 10 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
14. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 1 , wherein a pore-forming material is added to said mixed powder material.
15. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 14 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.
16. The method for producing an aluminum-titanate-based ceramic honeycomb structure according to claim 1 , wherein said molding is kept at the highest keeping temperature for 24 hours or longer.