JPH04130069A - Manufacture of honeycomb-type ceramic structure - Google Patents

Abstract

PURPOSE:To easily obtain a large-area ceramic structure for a carrier of catalyst for catalytic combustion by joining end surfaces of plural ceramic structure bodies with a material prepared by adding a lithium aluminosilicate powder to a ceramic powder of the same composition as the ceramic structure and then calcining. CONSTITUTION:For example, SiO2-Al2O3-TiO2-K2O ceramic material having small coefft. of thermal expansion is molded in a honeycomb structure by extrusion molding and then calcined to obtain four ceramic structures 1. On the other hand, a ceramic powder having the same composn. as that of the calcined ceramic body is prepared, and 98 pts.wt. of this powder is mixed with 2 pts.wt. of lithium aluminosilicate powder and added to an aq. soln. to which a little amt. of PVA is added to obtain a sludge. This sludge is applied on two faces of the joining part 4 to join the structures 1, then dried and calcined to weld the side walls of the honeycomb ceramic structures.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a composite large-area honeycomb ceramic structure used as a carrier for a catalyst for catalytic combustion.

BACKGROUND OF THE INVENTION Honeycomb-shaped ceramic structures have been widely used as carriers for catalyst bodies for catalytic combustion, as they allow fuel gas to pass therethrough without resistance and efficiently contact and react with the catalyst.

The manufacturing method involves selecting the shape and dimensions of a press-forming die according to the desired shape and size of the structure, preparing raw materials, extruding them using a press machine, drying and firing them, and producing a honeycomb-shaped ceramic structure. Therefore, for example, if you need a structure with a different size or shape than the molding die you are currently using, you will have to make a new press molding die. Dies are very expensive and are a major factor in increasing production costs unless the quantity of the same production lot is extremely large.Also, even if a large-area complete honeycomb ceramic structure is necessary, it is not easy to produce. Problems to be Solved by the Invention In the conventional manufacturing method described above, a plurality of small-area honeycomb-like ceramic structures are connected via a gas seal member, etc. If necessary, it is necessary to make a press molding die with large dimensions, and in some cases, the molding die becomes so large that it is impossible to manufacture the desired structure with current manufacturing equipment. In addition, it was difficult to produce large-area honeycomb-like ceramic structures with a high yield using the conventional method of connecting and using small-area honeycomb-like ceramic structures.The present invention solves the above problems. The object of the present invention is to provide a manufacturing method for easily manufacturing a large honeycomb-shaped ceramic structure with a large area.

Means for Solving the Problems The present invention achieves the above objects by bonding the end faces of a plurality of honeycomb-shaped ceramic structures with a material made by adding lithium aluminosilicate powder to ceramic powder having the same composition, and then firing. By doing so, a plurality of honeycomb-shaped ceramic structures are fused and a composite 41
．． It was designed to be larger.

Cordierite composition or 5iO2-A 120 s-T with a small coefficient of thermal expansion is widely used as a honeycomb-shaped ceramic structure for a catalyst carrier in catalytic combustion devices.
i O2-K The end faces of the honeycomb-shaped ceramic structure are bonded together using ceramic powder with the same composition as the O2-K 20 series ceramic material as an aggregate and lithium aluminosilicate as a binder, so the joints are almost the same as other parts. Due to the composition, the effective difference in coefficient of thermal expansion is small and damage due to thermal stress at the joint can be prevented.

Therefore, it is possible to obtain a honeycomb-shaped ceramic structure that does not break even during rapid cooling, has excellent so-called spalling properties, and has sufficient mechanical strength for practical use. Further, since it can be created by simply joining without creating a new large press molding die, manufacturing is easy and manufacturing costs can be reduced.

EXAMPLE Below, an example of the present invention is shown in FIGS. 1 to 2(a),
This will be explained with reference to (b).

Example 1 Rehydratable alumina 10-layer plate Fused silica 85 weight suit
Using 5 parts by weight of potassium titanate, extrusion molded into a honeycomb shape and fired at 1200°C for 1 hour L 150x15
0mm, thickness 10mm, cell density 300 cells/
in' (cell pitch 1, 5 m @ rib IFf0
．． After that, a powder with the same composition as the ceramic after firing (particle size of 100 mesh or less) was prepared.
Mix 8 parts by weight of lithium aluminosilicate powder (eucryptite powder) (particle size 100 mesh or less) with 2 parts by weight, and then add a small amount of polyvinyl alcohol (PVA).
) was added to make the mixed powder a slurry, and the slurry was applied to two places on the side end face of each honeycomb-shaped ceramic structure to be bonded. Bonding After drying, 11
The side end surfaces of the honeycomb ceramic structure were fused together by firing at 00°C for 1 hour.The firing temperature at this time should be set lower than the sintering temperature of the ceramic material powder and higher than the softening point of the lithium aluminosilicate. It is preferable that the ceramic powder be used as a plaster and the lithium aluminosilicate be used as a binder to bond the end surfaces of the honeycomb ceramic structure to each other.

As a result, as shown in FIG.
The honeycomb-shaped ceramic structure 2 was obtained by adding AlaOa.C to the honeycomb-shaped ceramic structure 2.
The catalyst body 3 for catalytic combustion and the catalyst body 3 for catalytic combustion of shinako were coated with 120 g of wash coat consisting of eO2 (A l 2 Qs: C602 = 10:3 weight ratio) and supported about 2 g of platinum group catalyst under actual usage conditions. 6000kc as shown in Figure 2(a) and (b) for testing.
In these figures, 4 is the joint of the small honeycomb ceramic structure, 5 is the frame, 6 is the fuel tank, 7 is the blower fan, 8 is the fuel pump, and 9 is the pre-heater. Mixing chamber 10 is auxiliary flame μ 11
13 is an exhaust path.

The obtained honeycomb-shaped ceramic structure 2 was evaluated by the following combustion condition test and fall test.9 First,
The combustion condition test was carried out by setting the fuel upstream side of the catalyst body of the catalytic combustion device at approximately 800°C. After burning for L1 hour, extinguishing L and cooling for 30 minutes for 1 cycle and LA 5000 cycles. 9. The results of the above test were honeycomb-shaped. There were no abnormalities in the joints of the ceramic structure.In the fall test, the bottom of the catalytic combustion device was made to avoid slipping, force was applied from the center of the top, and the device was caused to fall back and forth five times each. There was no abnormality in the joint part, and since eucryptite was used as the lithium aluminosilicate in this example (the same effect could be obtained even if spodumene was used). Structure 2
After preparing four sheets of powder, prepare a powder with the same composition (particle size of 100 mesh or less), take 98 parts by weight of the powder, and add lithium aluminosilicate powder (eucryptite powder) (particle size of 10 mesh or less).
0 mesh or less), 2 parts by weight of hydroxypropyl methyl cellulose, and the specified amount of water, and mix 150
After that, the surface of the sheet molded product was moistened with a small amount of water, and then the two side end faces of each honeycomb-shaped ceramic structure were shaped into a sheet with the sheet molded product having a size of 10 mm x 10 mm and a thickness of 1 mm. After joining and drying, it was fired at 1100°C for 1 hour to fuse the side end surfaces of the honeycomb-shaped ceramic structures to each other.As a result, the four small honeycomb-shaped ceramic structures 1 were integrated into one L.
300x300mm honeycomb ceramic structure 2
A120a/C can be obtained in the honeycomb-shaped ceramic structure 2.
A catalytic combustion catalyst body 3 was prepared by coating 120 g of a wash coat consisting of e0e (A1201: Ce02 = 10: 3 weight ratio) and supporting approximately 2 g of a platinum group catalyst. The same combustion condition test and fall test as in Example 1 were carried out.The results showed that there was no abnormality in the joints of the flat plates of the honeycomb-shaped ceramic structure. Naru Ceramics is 5iOp
80-92wt% Al2O35-18wt%, Ti
1t 2~6wt% K2O0゜4~1.5wt%
The composition of this ceramic is preferably 1000℃
From the above, sintering begins gradually, and alumina and potassium titanate gradually become a solid solution phase at the fused silica grain boundaries, resulting in 120
At 0°C, it has excellent mechanical strength. Also
The result is a ceramic that also has the low thermal expansion properties of the fused silica used.

Example 3 150x150m melon, thickness IDmm, cell density 30
0 cell/1n2 (cell pitch 1.5m, rib thickness 0.2
0 mm) small-sized cordierite porcelain honeycomb-shaped ceramic structures 1 were prepared, and then a powder (particle size of 100 mesh or less) having a cordierite porcelain composition was prepared. Mix 2 parts by weight of powder (spodumene powder) (particle size: 100 mesh or less), and then use an aqueous solution to which a small amount of PVA is added to turn the mixed powder into a slurry.
After applying the slurry to the parts, bonding and drying, 110
The side end surfaces of the small honeycomb ceramic structures 1 are fused together by firing at 0°C for 1 hour.As a result, the four small honeycomb ceramic structures 1 are integrated L30
A honeycomb-shaped ceramic structure 2 of 0x300 mm was obtained.Al2O3.C was added to the honeycomb-shaped ceramic structure 2.
The catalyst body 3 for catalytic combustion of this example was also coated with 120 g of wash coat consisting of eo2 (A I2O3: Ce02 = 10: 3 weight ratio) and supported about 2 g of platinum group catalyst. The same combustion condition test and fall test as in Example 1 were conducted, and the results showed that there were no abnormalities in the joints of the honeycomb-shaped ceramic structure 2.Here, the amount of lithium aluminosilicate powder added to the ceramic powder was 0.5 to 3 wt%. However, if the amount added is less than 0.5 wt%, sufficient adhesive strength will not be obtained, and if it exceeds 3 wt%, the heat resistance of the bonded portion will deteriorate.

It goes without saying that the manufacturing method of the present invention has similar effects not only on structures used as carriers for catalytic combustion catalysts, but also as a method for manufacturing other large honeycomb-shaped ceramic structures that are difficult to press-form. stomach.

Effects of the Invention As is clear from the above embodiments, the present invention (relatively small honeycomb-shaped ceramic structures can be easily connected to form a composite structure and can be made larger), and the adhesive strength and impact resistance at the joints can be increased. It is possible to easily produce a large honeycomb-shaped ceramic structure with good properties and heat resistance.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a honeycomb ceramic structure according to an embodiment of the present invention; Figure 2 (a) is a front view of a catalytic combustion device for evaluating a honeycomb ceramic structure.
FIG. 2(b) is a partial sectional view of the catalytic combustion device.

Claims (3)

[Claims] (1) The end surfaces of a plurality of honeycomb-shaped ceramic structures are bonded together using a material obtained by adding lithium aluminosilicate powder to ceramic powder having the same composition as the structure, and then fired and fused. A method for manufacturing a honeycomb ceramic structure. (2) After forming a sheet-like member using a material in which lithium aluminosilicate powder is added to ceramic powder having the same composition as that of the honeycomb-shaped ceramic structure, and joining a plurality of the structures with the sheet-like member interposed therebetween; . A method for manufacturing a honeycomb-shaped ceramic structure, which comprises firing and fusing the end surfaces of the structure. (3) The method for manufacturing a honeycomb-shaped ceramic structure according to claim 1 or 2, wherein the amount of lithium aluminosilicate powder added is 0.5 to 3 wt% based on the ceramic powder.