Honeycomb structure and method for manufacturing the same
A honeycomb structure 10 of the present invention is provided with porous partition walls 12 made of a ceramic material containing cordierite as a main crystal phase and separating and forming a plurality of cells 14 functioning as fluid passages. The partition walls 12 contain sodium at 0.08 to 0.15 mass % in terms of sodium oxide. A honeycomb structure having a large average pore size can be provided.
1. A honeycomb structure comprising porous partition walls made of a ceramic material containing cordierite as a main crystal phase and separating and forming a plurality of cells functioning as fluid passages,
wherein a thermal expansion coefficient of the honeycomb structure at 40 to 800° C. is 0.5×10 −6 to 0.9×10 −6 /° C., the partition walls contain sodium at 0.08 to 0.15 mass % in terms of sodium oxide, the partition walls were made from a cordierite-forming raw ceramic material containing at least a first alumina source containing sodium at 0.4 to 1.0 mass % in terms of sodium oxide as an alumina source for the cordierite, and formation of a glass phase containing sodium oxide is inhibited.
2. A honeycomb structure according to claim 1 , wherein a ratio (W/X) of a thickness W (μm) of the partition walls to an average pore size X (μm) of pores formed in the partition walls is less than 3.0.
3. A honeycomb structure according to claim 2 , wherein the partition walls have a thickness of 100 to 300 μm.
4. A honeycomb structure according to claim 2 , wherein the partition walls have a porosity of 59 to 67% and an average pore size of 30 to 110 μm.
5. A honeycomb structure according to claim 2 , wherein the thermal expansion coefficient at 40 to 800° is 0.5×10 −6 to 0.7×10 −6 /° C.
6. A honeycomb structure according to claim 1 , wherein the partition walls have a thickness of 100 to 300 μm.
7. A honeycomb structure according to claim 6 , wherein the partition walls have a porosity of 59 to 67% and an average pore size of 30 to 110 μm.
8. A honeycomb structure according to claim 6 , wherein a the thermal expansion coefficient at 40 to 800° is 0.5×10 −6 to 0.7×10 −6 /° C.
9. A honeycomb structure according to claim 1 , wherein the partition walls have a porosity of 59 to 67% and an average pore size of 30 to 110 μm.
10. A honeycomb structure according to claim 1 , wherein the thermal expansion coefficient at 40 to 800° C. is 0.5×10 −6 to 0.7×10 −6 /° C.
11. A honeycomb structure according to claim 1 , wherein the partition walls have an average pore size of 50 to 110 μm.
12. A method for manufacturing a honeycomb structure comprising the steps of:
preparing kneaded clay for forming made of a ceramic raw material containing a cordierite-forming raw material containing at least a first alumina source containing sodium at 0.4 to 1.0 mass % in terms of sodium oxide as an alumina source, and
forming the kneaded clay into a honeycomb shape where a plurality of cells functioning as fluid passages are separated and formed to obtain an unfired honeycomb formed article; and
producing a honeycomb structure in which a glass phase containing sodium oxide is inhibited, wherein the honeycomb structure has a thermal expansion coefficient at 40 to 800° C. is 0.5×10 −6 to 0.9×10 −6 /° C., and partition walls contain sodium at 0.08 to 0.15 mass % in terms of sodium oxide.