JP6062736B2 - Manufacturing method of honeycomb structure - Google Patents

Description

The present invention relates to the production how the honeycomb structure.

Recently, particulates (hereinafter also referred to as PM) contained in the exhaust gas discharged from internal combustion engines such as buses, trucks, passenger cars, etc. and construction machinery have been harmful to the surrounding environment or human body. It is a problem.
Therefore, various honeycomb structures made of porous ceramics have been proposed as filters for collecting PM in exhaust gas and purifying exhaust gas.

In such a honeycomb structure, the porosity is a very important factor for determining the performance of the filter. A honeycomb structure having a high porosity is desired from the relationship between an increase in the amount of catalyst supported and pressure loss.
Further, exhaust gas regulations are expected to be further strengthened in the future, and it is expected that a large amount of catalyst needs to be supported on the honeycomb structure. Therefore, development of a honeycomb structure having a higher porosity is awaited.

Patent Document 1 discloses a porous body (honeycomb structure) characterized by mixing, forming, and firing a raw material for a molded body containing a porous material for pores made of an organic polymer and inorganic particles and aggregate particles. ) Is disclosed.
Patent Document 1 discloses a porous body (honeycomb structure) having a porosity of 45 to 85%.

International Publication No. 2005/068397

Of the materials constituting the honeycomb structure, silicon carbide is preferably used because of its excellent heat resistance and thermal conductivity.
When manufacturing such a honeycomb structure made of silicon carbide, in the conventional manufacturing method described in Patent Document 1, silicon carbide particles are used as aggregate particles and fired at about 1000 to 2300 ° C.
However, Patent Document 1 does not disclose any method other than using silicon carbide particles as aggregate particles.

Further, when a honeycomb structure having a porosity exceeding 70% is manufactured using the conventional manufacturing method described in Patent Document 1, the shape of the formed body after the degreasing process is deformed by a slight external force. It turned out that.
For this reason, when manufacturing a honeycomb structure at the laboratory level, it is possible to handle such a degreased compact manually, but such degreasing is assumed when mass production of the honeycomb structure is assumed. It faces the problem that it is extremely difficult to transport the subsequent molded body by a machine.

An object of the present invention is to provide a novel method for producing a porous honeycomb structure made of silicon carbide.
Moreover, it aims at providing the manufacturing method of the honeycomb structure which can convey the molded object after degreasing as a preferable aspect of this invention easily.

A method for manufacturing a honeycomb structure of the present invention includes:
A honeycomb formed body preparing step of preparing a honeycomb formed body including carbon particles and having a number of cells arranged in parallel in the longitudinal direction across the cell wall;
And a reaction step of producing a porous silicon carbide honeycomb sintered body by reacting the carbon particles and molten silicon.

In the method for manufacturing a honeycomb structure of the present invention , unlike the conventional manufacturing method described in Patent Document 1, a honeycomb formed body containing carbon particles is prepared. Then, a porous silicon carbide honeycomb sintered body is produced by reacting the carbon particles with molten silicon.
The manufacturing method as described above is a novel method for manufacturing a porous honeycomb structure made of silicon carbide.

The method for manufacturing a honeycomb structured body of the present invention further includes a degreasing step for degreasing the honeycomb formed body before the reaction step.
By performing the degreasing step, organic substances contained in the honeycomb formed body can be removed.

In the method for manufacturing a honeycomb structured body of the present invention, the carbon particles are composed of two or more kinds of particles having different average particle diameters.
When the carbon particles are composed of two or more kinds of particles having different average particle diameters, the strength of the honeycomb formed body can be maintained even after the degreasing step. The particles having a relatively small average particle size aggregate and / or fill the grain boundary portion of the particles having a relatively large average particle size. Therefore, it is considered that the contact area between the carbon particles is increased, and the strength of the honeycomb formed body can be maintained.
As a result, even if mass production of the honeycomb structure is assumed, the degreased honeycomb molded body can be easily conveyed by a machine.

In the method for manufacturing a honeycomb structured body of the present invention, the carbon particles include amorphous coke having an average particle diameter of 10 to 20 μm.
In the method for manufacturing a honeycomb structured body of the present invention, the carbon particles preferably include carbon black having an average particle diameter of 40 to 80 nm .
When amorphous coke or carbon black is used as the carbon particles, the strength of the honeycomb formed body subjected to the degreasing step can be further maintained. Amorphous coke or carbon black contains a volatile component. Since this volatile component exerts a binder function for bonding the carbon particles in the degreasing step, it is considered that the strength of the honeycomb formed body can be further maintained.

In the method for manufacturing a honeycomb structure of the present invention, the carbon particles, and amorphous coke, it is preferably made of a carbon black having a smaller average particle diameter than the average particle size of the amorphous coke.
The relatively small carbon black aggregates and / or fills the grain boundary portion of the relatively large amorphous coke. Therefore, the contact area between carbon black and carbon black and between carbon black and amorphous coke is increased. In addition, the volatile components contained in the amorphous coke and carbon black exert a binder function between the carbon black and the carbon black and between the carbon black and the amorphous coke. As a result, it is considered that the strength of the honeycomb formed body can be maintained even after the degreasing step.

In the method for manufacturing a honeycomb structured body of the present invention, the honeycomb formed body may be impregnated with molten silicon in the reaction step.
Thus, carbon particles and molten silicon may be reacted by soaking silicon into a honeycomb formed body containing carbon particles.

In the method for manufacturing a honeycomb structured body of the present invention , in the honeycomb formed body preparing step, a honeycomb formed body including carbon particles and silicon particles may be prepared.
As described above, a honeycomb formed body containing carbon particles and silicon particles may be prepared, and the carbon particles and silicon particles in the honeycomb formed body may be reacted.

In the method for manufacturing a honeycomb structured body of the present invention , in the reaction step, silicon is preferably melted with an alkali metal flux.
By using an alkali metal, the melting point of silicon is lowered, so that silicon can be easily melted. Therefore, the reaction process can be performed efficiently, and as a result, a porous silicon carbide honeycomb sintered body can be efficiently manufactured.

In the method for manufacturing a honeycomb structure of the present invention, the alkali metal is preferably sodium.

In the method for manufacturing a honeycomb structured body of the present invention , in the honeycomb formed body preparing step, the honeycomb formed body may be manufactured by forming a raw material containing carbon particles.
That is, there may be a step of producing a honeycomb formed body before the reaction step.

The method for manufacturing a honeycomb structure of the present invention preferably further includes a sealing step of filling a plug material paste so that any one end of the cells of the honeycomb formed body is sealed.
By sealing any one end of the cell, a honeycomb structure functioning as a filter for collecting PM in the exhaust gas can be manufactured.

The honeycomb structure of the present invention is
A honeycomb structure including a porous silicon carbide honeycomb sintered body in which a large number of cells are arranged side by side in the longitudinal direction across a cell wall,
In the X-ray diffraction (XRD) profile of the silicon carbide honeycomb sintered body, the crystal structure of silicon carbide is 3C.
The crystal structure of the silicon carbide, may be made of only 3 C, 2 H, 4H, it may further comprise at least one of 6H and 15R.

A silicon carbide honeycomb sintered body produced by reacting carbon particles with molten silicon is a silicon carbide honeycomb fired article produced by firing a honeycomb formed body containing silicon carbide particles in the above points. It is different from the body.

Here, in the silicon carbide honeycomb fired body manufactured by firing the honeycomb fired body containing silicon carbide, the crystal structure of silicon carbide is mainly composed of 4H and 6H.
Since the 3C crystal structure is easily stretched in the plate-like or columnar direction, the fracture toughness is increased and the mechanical properties are slightly superior to those of the 4H and 6H crystal structures having an equiaxed particle shape. Therefore, the silicon carbide honeycomb sintered body composed of the 3C crystal structure is excellent in mechanical strength.
As described above, the honeycomb structure of the present invention can withstand vibration during use even if the silicon carbide honeycomb fired body has a high porosity.

The honeycomb structure of the present invention is manufactured by the method for manufacturing a honeycomb structure of the present invention .

In the honeycomb structure of the present invention , the porosity of the silicon carbide honeycomb sintered body is preferably 70 to 95%.
Therefore, a large amount of catalyst can be supported on the honeycomb structure.

The honeycomb formed body of the present invention ,
A honeycomb formed body in which a large number of cells are arranged in parallel in the longitudinal direction across a cell wall,
It is produced by molding a raw material containing carbon particles.

Fig.1 (a) is a perspective view which shows typically an example of the honeycomb molded body which concerns on 1st embodiment of this invention. Fig. 1 (b) is a cross-sectional view taken along line AA of the honeycomb formed body shown in Fig. 1 (a). FIG. 2 is a perspective view schematically showing an example of the honeycomb structure according to the first embodiment of the present invention. FIG. 3A is a perspective view schematically showing an example of a honeycomb sintered body constituting the honeycomb structure shown in FIG. FIG. 3B is a cross-sectional view of the honeycomb sintered body shown in FIG. FIG. 4 is an X-ray diffraction profile of the silicon carbide honeycomb sintered body constituting the honeycomb structure according to the first embodiment of the present invention. FIG. 5 is an X-ray diffraction profile of a silicon carbide honeycomb fired body produced by firing a honeycomb formed body containing silicon carbide. 6 (a) and 6 (b) are SEM images of a cross section of the silicon carbide honeycomb sintered body produced in Example 1. FIG. Fig.7 (a) is a perspective view which shows typically an example of the honeycomb structure which concerns on other embodiment of this invention. FIG.7 (b) is CC sectional view taken on the line of the honeycomb structure shown to Fig.7 (a).

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the following embodiments, and can be applied with appropriate modifications without departing from the scope of the present invention.

(First embodiment)
Hereinafter, a honeycomb structure manufacturing method, a honeycomb structure, and a first embodiment which is an embodiment of a honeycomb formed body of the present invention will be described.

The manufacturing method of the honeycomb structure according to the first embodiment of the present invention,
A honeycomb formed body preparing step of preparing a honeycomb formed body including carbon particles and having a number of cells arranged in parallel in the longitudinal direction across the cell wall;
And a reaction step of producing a porous silicon carbide honeycomb sintered body by reacting carbon particles and molten silicon.
In the method for manufacturing a honeycomb structure according to the first embodiment of the present invention, the honeycomb formed body is impregnated with molten silicon in the reaction step.

Hereinafter, each step will be described.
In the present specification, “silicon carbide honeycomb sintered body” is also simply referred to as “honeycomb sintered body”.

First, a honeycomb formed body preparation step is performed in which a honeycomb formed body containing carbon particles and having a large number of cells arranged in parallel in the longitudinal direction with cell walls interposed therebetween is prepared.

The method for preparing the honeycomb formed body is not particularly limited, but for example, by forming a raw material containing carbon particles, a honeycomb formed body in which a large number of cells are arranged in parallel in the longitudinal direction with the cell walls therebetween may be manufactured. it can.
Specifically, first, a raw material (wet mixture) for manufacturing a honeycomb formed body is prepared by mixing a powder containing carbon particles, a pore former, an organic binder, and water.
Next, the wet mixture is put into an extruder and extruded, and then cut into a predetermined length to produce a raw honeycomb molded body having a predetermined shape.
Thereafter, the raw honeycomb molded body is dried using a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, a freeze dryer, or the like to produce a honeycomb molded body. To do.

As the powder containing carbon particles, for example, a mixture of amorphous coke and carbon black having an average particle size smaller than the average particle size of the amorphous coke can be used.
In this case, it is preferable to use a mixture of amorphous coke having an average particle diameter of 10 to 20 μm and carbon black having an average particle diameter of 40 to 80 nm as the powder containing carbon particles.

The honeycomb formed body manufactured as described above is a honeycomb formed body according to the first embodiment of the present invention.
Fig.1 (a) is a perspective view which shows typically an example of the honeycomb molded body which concerns on 1st embodiment of this invention. Fig. 1 (b) is a cross-sectional view taken along line AA of the honeycomb formed body shown in Fig. 1 (a).
In the honeycomb formed body 10 shown in FIGS. 1 (a) and 1 (b), a large number of cells 11 are arranged in parallel in the longitudinal direction (in the direction of arrow a in FIG. 1 (a)) with a cell wall 12 therebetween. In addition, an outer peripheral wall 13 is formed around the periphery.

In this specification, the honeycomb formed body has a concept including a raw honeycomb formed body.

Thereafter, it is preferable to perform a degreasing step of degreasing the honeycomb formed body.
For example, the organic matter in the honeycomb formed body is removed by heating the honeycomb formed body at 500 to 700 ° C. in a nitrogen atmosphere.

Subsequently, a reaction step of producing a porous silicon carbide honeycomb sintered body by reacting carbon particles and molten silicon is performed.

Specifically, the honeycomb formed body is impregnated with molten silicon and subjected to reactive sintering.
For example, first, the honeycomb formed body and the metal silicon powder are put in the same crucible and heated in an inert atmosphere to melt the metal silicon. A porous silicon carbide honeycomb sintered body can be manufactured by impregnating the honeycomb formed body with molten silicon. Note that the metal silicon may not be powder.

In the reaction step, it is preferable to impregnate the honeycomb formed body with silicon melted by an alkali metal flux.
Specifically, the alkali metal is put in a crucible different from the crucible containing the honeycomb formed body and the metal silicon powder, and the two crucibles are heated in the same container. And silicon can be melted by using alkali metal as a vapor.
Since the melting point of silicon can be lowered by using an alkali metal flux, silicon can be easily melted. Therefore, the reaction process can be performed efficiently, and as a result, a porous silicon carbide honeycomb sintered body can be efficiently manufactured.

Examples of the alkali metal include lithium, sodium and potassium. These may be used alone or in combination of two or more.
Of the alkali metals, sodium is preferred.
In addition to the alkali metal, the flux may contain other elements such as an alkaline earth metal (for example, calcium).

When the honeycomb molded body is impregnated with silicon melted by an alkali metal flux, the reaction process conditions are preferably 700 to 900 ° C. and 18 to 36 hours.
The reaction step is preferably performed in an inert atmosphere, and more preferably performed in an argon atmosphere.

In order to evaporate the alkali metal which is a flux component after the reaction step, a heating step of heating at 700 to 800 ° C. may be performed in an inert atmosphere.
In the heating step, the alkali metal component adhering to the honeycomb sintered body can be evaporated and unreacted carbon can be removed.

By passing through the above steps, a porous silicon carbide honeycomb sintered body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween can be produced.

In the method for manufacturing a honeycomb structured body according to the first embodiment of the present invention, a honeycomb sintered body in which either one end of the cell is sealed can be manufactured. In this case, after the honeycomb formed body is manufactured, a sealing step of sealing a cell by filling a predetermined amount of a sealing material paste as a sealing material into a predetermined end of the cell of the honeycomb formed body is performed. Good.
After the sealing step, the above-described reaction treatment (when the degreasing step is performed, the degreasing step and the reaction step) is performed to produce a honeycomb sintered body in which either one end of the cell is sealed. be able to.
By sealing any one end of the cell, a honeycomb structure functioning as a filter for collecting PM in the exhaust gas can be manufactured.
The sealing material paste can be produced, for example, by mixing a powder containing carbon particles, a binder, and a solvent.

Subsequently, a ceramic block is manufactured using at least one honeycomb sintered body.
As an example, a method for producing a ceramic block in which a plurality of honeycomb sintered bodies are bundled through an adhesive layer will be described.
First, an adhesive paste serving as an adhesive layer is applied to each predetermined side surface of the honeycomb sintered body to form an adhesive paste layer, and another honeycomb sintered body is sequentially formed on the adhesive paste layer. The process of laminating the bodies is repeated to produce an aggregate of honeycomb sintered bodies.
Next, a ceramic block is manufactured by heating the aggregate of honeycomb sintered bodies to dry and solidify the adhesive paste layer to form an adhesive layer.
Here, as the adhesive paste, for example, a paste made of an inorganic binder, an organic binder, and inorganic particles is used. The adhesive paste may further contain inorganic fibers and / or whiskers.

Thereafter, the ceramic block is cut.
Specifically, a ceramic block whose outer periphery is processed into a columnar shape is manufactured by cutting the outer periphery of the ceramic block using a diamond cutter or the like.

Furthermore, an outer periphery coating material paste is applied to the outer peripheral surface of the cylindrical ceramic block, and dried and solidified to form an outer periphery coating layer.
Here, the said adhesive paste can be used as an outer periphery coating material paste. Note that a paste having a composition different from that of the adhesive paste may be used as the outer periphery coating material paste.
Further, the outer peripheral coat layer is not necessarily provided, and may be provided as necessary.
A honeycomb structure can be manufactured by the above process.

Hereinafter, the honeycomb structure according to the first embodiment of the present invention will be described.
FIG. 2 is a perspective view schematically showing an example of the honeycomb structure according to the first embodiment of the present invention.
FIG. 3A is a perspective view schematically showing an example of a honeycomb sintered body constituting the honeycomb structure shown in FIG. FIG. 3B is a cross-sectional view of the honeycomb sintered body shown in FIG.

In the honeycomb structure 100 shown in FIG. 2, a plurality of honeycomb sintered bodies 110 are bound together via an adhesive layer 101 to form a ceramic block 103, and an outer peripheral coat layer 102 is formed on the outer periphery of the ceramic block 103. Is formed. In addition, the outer periphery coating layer should just be formed as needed.
The honeycomb sintered body 110 has a shape shown in FIGS. 3 (a) and 3 (b).
Such a honeycomb structure in which a plurality of honeycomb sintered bodies are bundled is also referred to as a collective honeycomb structure.

In the honeycomb sintered body 110 shown in FIGS. 3 (a) and 3 (b), a large number of cells 111 are arranged in parallel in the longitudinal direction (in the direction of arrow b in FIG. 3 (a)) with the cell walls 112 therebetween. In addition, an outer peripheral wall 113 is formed around the periphery. One end of the cell 111 is sealed with a sealing material 114.
Therefore, the exhaust gas G (in FIG. 3B, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by an arrow in FIG. 3B) has always passed through the cell wall 112 separating the cells 111. Then, the other end surface flows out from the other cell 111 opened. When the exhaust gas G passes through the cell wall 112, PM and the like in the exhaust gas are collected, so that the cell wall 112 functions as a filter.
Thus, a honeycomb structure including a honeycomb sintered body in which either one end of a cell is sealed can be suitably used as a ceramic filter.

In the honeycomb structure according to the first embodiment of the present invention, in the X-ray diffraction (XRD) profile of the silicon carbide honeycomb sintered body, the crystal structure of silicon carbide is 3C type.
In the honeycomb structure according to the first embodiment of the present invention, the crystal structure of silicon carbide may be composed only of 3C, or a crystal structure other than 3C to the extent that the effects of the present invention are not hindered. May be included. Examples of the crystal structure other than 3C include 2H, 4H, 6H, and 15R. Any one of these crystal structures other than 3C may be included, or two or more thereof may be included.

FIG. 4 is an X-ray diffraction profile of the silicon carbide honeycomb sintered body constituting the honeycomb structure according to the first embodiment of the present invention.
4 that the silicon carbide honeycomb sintered body constituting the honeycomb structure according to the first embodiment of the present invention has a silicon carbide crystal structure mainly composed of 3C.
On the other hand, FIG. 5 is an X-ray diffraction profile of a silicon carbide honeycomb fired body produced by firing a honeycomb formed body containing silicon carbide.
FIG. 5 shows that in the silicon carbide honeycomb fired body manufactured by firing the honeycomb formed body containing silicon carbide, the crystal structure of silicon carbide is mainly composed of 4H and 6H.

The silicon carbide honeycomb sintered body constituting the honeycomb structure according to the first embodiment of the present invention is mainly composed of silicon carbide particles. Specifically, the silicon carbide honeycomb sintered body contains 60% by weight or more of silicon carbide. The silicon carbide honeycomb sintered body is configured by bonding a large number of silicon carbide particles as an aggregate while maintaining a large number of pores therebetween.
In addition, the silicon carbide honeycomb sintered body may contain components other than silicon carbide as long as silicon carbide is contained in an amount of 60% by weight or more. For example, the silicon carbide honeycomb sintered body may contain 40% by weight or less of silicon. The main component of the constituent material of the silicon carbide honeycomb sintered body may be silicon-containing silicon carbide in which metal silicon is blended with silicon carbide, or silicon carbide bonded with silicon or a silicate compound. Also good.
Among these, the silicon carbide honeycomb sintered body preferably contains 98% by weight or more of silicon carbide or 98% by weight or more of silicon carbide and metal silicon.

The porosity of the silicon carbide honeycomb sintered body constituting the honeycomb structure according to the first embodiment of the present invention is preferably 70 to 95%.
The porosity of the silicon carbide honeycomb sintered body can be adjusted, for example, by changing the particle diameter of the pore former contained in the wet mixture, the content of the pore former, and the particle diameter of the carbon particles. .

The porosity of the honeycomb sintered body can be measured by the following method.
First, a 150 times SEM image is taken using a scanning electron microscope (SEM) for an arbitrary cross section (cross cut) of the honeycomb sintered body. Next, the SEM image is binarized (black and white photography). At this time, a white part corresponds to a base material and a black part corresponds to a pore. Then, the boundary between the white portion and the black portion in the binarized SEM image is determined, and the binarized SEM image is taken into Luzex software. On the captured image, a strip having a thickness of 1 bit in the horizontal direction is created. Therefore, in each strip, the distance from the black portion to the black portion (distance of the black portion) and the distance from the white portion to the white portion (distance of the white portion) are measured. From all the measurement results, the ratio of the distance of the black portion to the sum of the distance of the black portion and the distance of the white portion is calculated, and this value is taken as the porosity of the honeycomb sintered body.

The honeycomb structure according to the first embodiment of the present invention can be manufactured by the method for manufacturing a honeycomb structure according to the first embodiment of the present invention.

Hereinafter, the manufacturing method of the honeycomb structure of the present embodiment and the function and effect of the honeycomb structure will be described.
(1) In the method for manufacturing a honeycomb structure according to the present embodiment, a honeycomb formed body containing carbon particles is prepared. Then, a porous silicon carbide honeycomb sintered body is produced by reacting the carbon particles with molten silicon.
The manufacturing method as described above is a novel method for manufacturing a porous honeycomb structure made of silicon carbide.

(2) In the method for manufacturing a honeycomb structure of the present embodiment, the carbon particles are composed of amorphous coke and carbon black having an average particle size smaller than the average particle size of the amorphous coke.
When the carbon particles are composed of two types of particles having different average particle diameters, the strength of the honeycomb formed body can be maintained even when the degreasing step is performed. The particles having a relatively small average particle size aggregate and / or fill the grain boundary portion of the particles having a relatively large average particle size. Therefore, it is considered that the contact area between the carbon particles is increased, and the strength of the honeycomb formed body can be maintained.
As a result, even if mass production of the honeycomb structure is assumed, the degreased honeycomb molded body can be easily conveyed by a machine.

(3) Further, when amorphous coke and carbon black are used as the carbon particles, the strength of the honeycomb formed body subjected to the degreasing process can be further maintained. Amorphous coke and carbon black contain volatile components. Since this volatile component exerts a binder function for bonding the carbon particles in the degreasing step, it is considered that the strength of the honeycomb formed body can be further maintained.

(4) Further, the relatively small carbon black aggregates and / or fills the grain boundary portion of the relatively large amorphous coke. Therefore, the contact area between carbon black and carbon black and between carbon black and amorphous coke is increased. In addition, the volatile components contained in the amorphous coke and carbon black exert a binder function between the carbon black and the carbon black and between the carbon black and the amorphous coke. As a result, it is considered that the strength of the honeycomb formed body can be maintained even after the degreasing step.

(5) The honeycomb structure of the present embodiment is manufactured by the method for manufacturing a honeycomb structure of the present embodiment.
A silicon carbide-based honeycomb sintered body produced by reacting carbon particles with molten silicon is produced by firing a honeycomb formed body containing silicon carbide particles in that the crystal structure of silicon carbide is 3C. This is different from the silicon carbide honeycomb fired body.
A silicon carbide honeycomb sintered body composed of a 3C crystal structure is excellent in mechanical strength. Therefore, the honeycomb structure of the present embodiment can withstand vibration during use even if the silicon carbide honeycomb fired body has a high porosity.

Examples that more specifically disclose the first embodiment of the present invention will be described below. In addition, this invention is not limited only to this Example.
Example 1
A mixture of 12% by weight of amorphous coke powder having an average particle diameter of 12 μm, 5% by weight of carbon black powder having an average particle diameter of 50 nm, and 41% by weight of acrylic particles having an average particle diameter of 40 μm as a pore former is obtained. It was. To the obtained mixture, 3% by weight of methylcellulose and 39% by weight of ion-exchanged water were added as an organic binder, and kneaded using a plastograph (manufactured by Brabender, W30 / W50 type) to obtain a wet mixture. .

The wet mixture is put into a hydraulic jack type batch extruder (P-18, manufactured by Riken Seiki Co., Ltd.), and the wet mixture is extruded using a mold and cut. A raw honeycomb formed body having substantially the same shape as that shown in FIG. 3B and having no cells sealed was produced.

Next, the raw honeycomb formed body was dried at 100 ° C. for 24 hours using a hot air dryer, thereby manufacturing a honeycomb formed body.

The cells were sealed by filling a predetermined cell of the honeycomb formed body with a sealing material paste.
The sealing material paste was produced by mixing the above-mentioned amorphous coke powder, carbon black powder, binder, and solvent.

The honeycomb molded body in which the cells were sealed was degreased at 600 ° C. for 2 hours in an atmosphere of 100% by volume of nitrogen.

The metal silicon powder and the honeycomb formed body subjected to the degreasing treatment were put in the same crucible. Sodium was put in another crucible.
The two crucibles were put in the same reaction vessel, and the inside of the reaction vessel was sealed with argon gas.

The above honeycomb molded body and the like were heated at 800 ° C. for 24 hours to perform reactive sintering.
A silicon carbide honeycomb sintered body was manufactured by melting metal silicon with sodium vapor and allowing the honeycomb formed body to soak in the molten silicon.

Furthermore, it heated at 700 degreeC for 24 hours in argon atmosphere, and sodium was evaporated.

Thereafter, the produced silicon carbide honeycomb sintered body was taken out from the reaction vessel.
The silicon carbide honeycomb sintered body produced in Example 1 has a porosity of 80%, a size of 10 mm × 10 mm × 10 mm, and a number of cells (cell density) of 31.0 / cm ² (200 / inch). ² ) The cell wall thickness was 0.4 mm.
The porosity of the silicon carbide honeycomb sintered body was measured using a scanning electron microscope (SEM) image.
6 (a) and 6 (b) are SEM images of a cross section of the silicon carbide honeycomb sintered body produced in Example 1. FIG.

Next, 30% by weight of alumina fibers having an average fiber length of 20 μm, 21% by weight of silicon carbide particles having an average particle diameter of 0.6 μm, 15% by weight of silica sol, 5.6% by weight of carboxymethylcellulose, and 28.4% by weight of water were added. A heat resistant adhesive paste containing was prepared.
Then, an adhesive paste is applied to the side surface of the honeycomb sintered body, and the honeycomb sintered body is bonded to the honeycomb sintered body by adhering a total of 16 pieces of the above-mentioned honeycomb sintered body 4 in length and 4 in width. An assembly was produced.
Furthermore, the ceramics having a square pillar shape in which an adhesive layer having a thickness of 1.0 mm is formed by heating an aggregate of honeycomb sintered bodies at 180 ° C. for 45 minutes to dry and solidify the adhesive paste. A block was made.

Then, the ceramic block by which the outer periphery was processed into the column shape was produced by cut | disconnecting the outer periphery of a ceramic block using a diamond cutter.
Next, the outer periphery coating material paste was applied to the outer peripheral surface of the ceramic block whose outer periphery was processed into a columnar shape to form an outer periphery coating material paste layer.
At this time, a paste having the same composition as the adhesive paste was used as the outer periphery coating material paste.
Then, the outer peripheral coating material paste layer was dried and solidified at 120 ° C. for 60 minutes to form an outer peripheral coating layer, whereby a cylindrical honeycomb structure having an outer peripheral coating layer formed on the outer periphery was produced.

In Example 1, a honeycomb structure including a silicon carbide honeycomb sintered body having a high porosity of 80% could be manufactured.
Further, in Example 1, it was confirmed that the shape of the honeycomb formed body after the degreasing treatment was not broken even when the honeycomb formed body was grasped with tweezers. It is considered that such a honeycomb formed body can sufficiently withstand the mechanical conveyance during mass production.

(Second embodiment)
Hereinafter, a method for manufacturing a honeycomb structure of the present invention, a honeycomb structure, and a second embodiment which is an embodiment of a honeycomb formed body will be described.

The manufacturing method of the honeycomb structure according to the second embodiment of the present invention,
A honeycomb formed body preparing step of preparing a honeycomb formed body including carbon particles and having a number of cells arranged in parallel in the longitudinal direction across the cell wall;
And a reaction step of producing a porous silicon carbide honeycomb sintered body by reacting carbon particles and molten silicon.
In the method for manufacturing a honeycomb structured body according to the second embodiment of the present invention, a honeycomb formed body including carbon particles and silicon particles is prepared in the honeycomb formed body preparing step.

Hereinafter, each step will be described.

First, a honeycomb formed body preparation step is performed in which a honeycomb formed body including carbon particles and silicon particles and having a large number of cells arranged in parallel in the longitudinal direction with cell walls interposed therebetween is prepared.

The method for preparing the honeycomb formed body is not particularly limited. For example, by forming a raw material containing carbon particles and silicon particles, a honeycomb formed body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween is manufactured. can do.
Specifically, first, a raw material (wet mixture) for manufacturing a honeycomb formed body is prepared by mixing a powder containing carbon particles, a powder containing silicon particles, a pore former, an organic binder, and water. Prepare.
Next, the wet mixture is put into an extruder and extruded, and then cut into a predetermined length to produce a raw honeycomb molded body having a predetermined shape.
Thereafter, the raw honeycomb molded body is dried using a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, a freeze dryer, or the like to produce a honeycomb molded body. To do.

The honeycomb formed body preparation step in the second embodiment of the present invention is common to the honeycomb formed body preparation step in the first embodiment of the present invention, except that the wet mixture further contains silicon particles. Therefore, the detailed description regarding the powder containing carbon particles is omitted.

The honeycomb formed body manufactured as described above is a honeycomb formed body according to the second embodiment of the present invention.
The honeycomb formed body according to the second embodiment of the present invention is common to the honeycomb formed body according to the first embodiment of the present invention except that the honeycomb formed body further includes silicon particles. Therefore, detailed description thereof is omitted.

Thereafter, it is preferable to perform a degreasing step of degreasing the honeycomb formed body.
Since the conditions of the degreasing process in the second embodiment of the present invention are the same as the conditions of the degreasing process in the first embodiment of the present invention, detailed description thereof is omitted.

Subsequently, a reaction step of producing a porous silicon carbide honeycomb sintered body by reacting carbon particles and molten silicon is performed.

Specifically, carbon and silicon in the honeycomb formed body are reactively sintered.
For example, first, the honeycomb formed body is put in a crucible and heated in an inert atmosphere to melt silicon in the honeycomb formed body. A porous silicon carbide honeycomb sintered body can be produced by reacting molten silicon with carbon particles in the honeycomb formed body.

In the reaction step, it is preferable to react carbon and silicon in the honeycomb formed body with an alkali metal flux.
Specifically, an alkali metal is put in a crucible different from the crucible containing the honeycomb formed body, and the two crucibles are heated in the same container. And silicon in the honeycomb formed body can be melted by using alkali metal as a vapor. As a result, the molten silicon can be reacted with the carbon particles in the honeycomb formed body.

Examples of the alkali metal include lithium, sodium and potassium. These may be used alone or in combination of two or more.
Of the alkali metals, sodium is preferred.
In addition to the alkali metal, the flux may contain other elements such as an alkaline earth metal (for example, calcium).

Since the conditions for the reaction step in the second embodiment of the present invention are the same as the conditions for the reaction step in the first embodiment of the present invention, detailed description thereof will be omitted.

In order to evaporate the alkali metal which is a flux component after the reaction step, a heating step of heating at 700 to 800 ° C. may be performed in an inert atmosphere.

By passing through the above steps, a porous silicon carbide honeycomb sintered body in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween can be produced.

In the method for manufacturing a honeycomb structured body according to the second embodiment of the present invention, a honeycomb sintered body in which either one end of the cell is sealed can be manufactured. In this case, a sealing step may be performed after the honeycomb formed body is manufactured.
After the sealing step, the above-described reaction treatment (when the degreasing step is performed, the degreasing step and the reaction step) is performed to produce a honeycomb sintered body in which either one end of the cell is sealed. be able to.
Since the conditions for the sealing step in the second embodiment of the present invention are the same as the conditions for the sealing step in the first embodiment of the present invention, detailed description thereof is omitted.

Thereafter, the step of producing the ceramic block, the step of cutting the ceramic block, and the step of forming the outer peripheral coating layer as necessary, described in the method for manufacturing the honeycomb structure according to the first embodiment of the present invention. By performing the above, a honeycomb structure can be manufactured.

The honeycomb structure according to the second embodiment of the present invention has the same configuration as the honeycomb structure according to the first embodiment of the present invention.

The honeycomb structure according to the second embodiment of the present invention is characterized in that, in the X-ray diffraction (XRD) profile of the silicon carbide honeycomb sintered body, the crystal structure of silicon carbide is 3C type.
In the honeycomb structure according to the second embodiment of the present invention, the crystal structure of silicon carbide may be composed only of 3C, or a crystal structure other than 3C to the extent that the effects of the present invention are not hindered. May be included. Examples of the crystal structure other than 3C include 2H, 4H, 6H, and 15R. Any one of these crystal structures other than 3C may be included, or two or more thereof may be included.

The silicon carbide honeycomb sintered body constituting the honeycomb structure according to the second embodiment of the present invention is mainly composed of silicon carbide particles. Specifically, the silicon carbide honeycomb sintered body contains 60% by weight or more of silicon carbide.
Since the silicon carbide honeycomb sintered body has been described in the first embodiment of the present invention, a detailed description thereof will be omitted.

The porosity of the silicon carbide honeycomb sintered body constituting the honeycomb structure according to the second embodiment of the present invention is preferably 70 to 95%.

The honeycomb structure according to the second embodiment of the present invention can be manufactured by the method for manufacturing a honeycomb structure according to the second embodiment of the present invention.

In the second embodiment of the present invention, the effects (1) to (5) described in the first embodiment of the present invention can be exhibited.

(Other embodiments)
In the method for manufacturing a honeycomb structure according to the first embodiment of the present invention, the method for producing a ceramic block in which a plurality of honeycomb sintered bodies are bundled through an adhesive layer has been described.
However, in the method for manufacturing a honeycomb structure according to the embodiment of the present invention, a ceramic block may be manufactured using one honeycomb sintered body. That is, you may manufacture the honeycomb structure which consists of one honeycomb sintered compact. Such a honeycomb structure made of one honeycomb sintered body is also referred to as an integral honeycomb structure.

Fig.7 (a) is a perspective view which shows typically an example of the honeycomb structure which concerns on other embodiment of this invention. FIG.7 (b) is CC sectional view taken on the line of the honeycomb structure shown to Fig.7 (a).
In the honeycomb structure 200 shown in FIGS. 7A and 7B, a large number of cells 211 are arranged in parallel in the longitudinal direction (in the direction of arrow c in FIG. 7A) with the cell walls 212 interposed therebetween. The ceramic block 203 is formed of one honeycomb sintered body having a substantially cylindrical shape, and an outer peripheral coat layer 202 is formed around the ceramic block 203. In addition, the outer periphery coating layer should just be formed as needed.

In the honeycomb structure 200 shown in FIG. 7A and FIG. 7B, either end of the cell 211 is sealed with a sealing material 214. Accordingly, the exhaust gas G (in FIG. 7B, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by an arrow in FIG. 7B) always passes through the cell wall 212 separating the cells 211. Thereafter, the other end face flows out from the open cell 211. Therefore, the cell wall 212 functions as a filter for collecting PM and the like.

In the case of manufacturing an integral honeycomb structure, the size of the honeycomb formed body formed by extrusion is larger than the size of the honeycomb formed body described in the first embodiment of the present invention, and the outer shape thereof is different. Otherwise, the honeycomb formed body is manufactured in the same manner as in the first embodiment of the present invention.
That is, the honeycomb molded body may be manufactured using a mold having the same configuration as the mold used in the first embodiment of the present invention, except that it has a cross-sectional shape corresponding to the shape of the obtained honeycomb molded body. .

Other processes are the same as the manufacturing process of the honeycomb structure described in the first embodiment of the present invention. However, since the honeycomb structure is composed of one honeycomb sintered body, it is not necessary to produce an aggregate of honeycomb sintered bodies. Moreover, when producing a columnar honeycomb molded body, it is not necessary to cut the outer periphery of the ceramic block.

In the method for manufacturing a honeycomb structure according to an embodiment of the present invention, a plurality of types of honeycomb sintered bodies having different cross-sectional shapes are manufactured, and the plurality of types of honeycomb sintered bodies are combined to form the honeycomb sintered body as an adhesive layer. You may produce the ceramic block formed by bundling through two. Thereby, cutting the outer periphery of the ceramic block can be omitted.
Note that honeycomb sintered bodies having different cross-sectional shapes can be produced by changing the shape of the mold. In this case as well, a honeycomb molded body was manufactured using a mold having the same configuration as that of the mold used in the first embodiment of the present invention, except that it had a cross-sectional shape corresponding to the shape of the obtained honeycomb molded body. do it.

In the method for manufacturing a honeycomb structure according to an embodiment of the present invention, when producing a ceramic block in which a plurality of honeycomb sintered bodies are bundled through an adhesive layer, the adhesive paste is applied to the side surface of each honeycomb sintered body. In addition to the method of applying to each other, for example, each honeycomb sintered body is temporarily fixed in a mold having the same shape as the shape of the ceramic block (or aggregate of honeycomb sintered bodies) to be manufactured, You may carry out by the method etc. which inject | pour between honeycomb sintered compacts.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, the degreasing step for degreasing the honeycomb formed body is not an essential step.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, when the honeycomb formed body is degreased, the conditions for the degreasing step are not particularly limited, and are appropriately selected depending on the type and amount of organic matter contained in the honeycomb formed body. 500 to 700 ° C., preferably 2 to 3 hours.
The degreasing step is preferably performed in an inert atmosphere, and more preferably performed in an atmosphere containing nitrogen or argon. The nitrogen concentration in the atmosphere (content converted to nitrogen) is not particularly limited, but is preferably 85 to 100% by volume.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, the sealing step of filling the plug material paste so as to seal any one end of the cells of the honeycomb formed body is an indispensable step. Absent.
A honeycomb structure including a honeycomb sintered body in which neither end of the cell is sealed can be suitably used as a catalyst carrier.

In the method for manufacturing a honeycomb structure according to the first embodiment of the present invention, as the powder containing carbon particles contained in the wet mixture, amorphous coke and carbon black having an average particle size smaller than the average particle size of the amorphous coke are used. The case of using a mixture with was explained.
However, in the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the powder containing carbon particles is not particularly limited.
Among the powders containing carbon particles, a powder made of amorphous carbon is preferable. Specific examples of the amorphous carbon include amorphous coke, carbon black, activated carbon, and resin carbide. These may be used alone or in combination of two or more. Amorphous coke and carbon black are more preferable.

In the method for manufacturing a honeycomb structure according to the first embodiment of the present invention, the case where the carbon particles are composed of two types of particles having different average particle diameters has been described.
However, in the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the honeycomb structure may be composed of one type of particles having different average particle sizes, or may be composed of two or more types of particles having different average particle sizes. .

As long as the average particle diameter is different, as the powder containing carbon particles, the same type of powder may be used, or different types of powder may be used.
In particular, the carbon particles are preferably composed of amorphous coke and carbon black having an average particle size smaller than the average particle size of the amorphous coke.
In this case, the carbon particles are more preferably composed of amorphous coke having an average particle diameter of 10 to 20 μm and carbon black having an average particle diameter of 40 to 80 nm.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the content of the powder containing carbon particles in the wet mixture is preferably 10 to 30% by weight, and more preferably 10 to 20% by weight. preferable.
When the content of the powder containing carbon particles is less than 10% by weight, the content of silicon carbide constituting the honeycomb sintered body after the reaction step becomes too small, so that the strength of the honeycomb sintered body can be sufficiently obtained. It becomes difficult. On the other hand, if the content of the powder containing carbon particles exceeds 30% by weight, the content of the pore former in the wet mixture becomes too small, and it becomes difficult to obtain a honeycomb sintered body having a high porosity.

In the method for manufacturing a honeycomb structure according to an embodiment of the present invention, the pore former contained in the wet mixture is not particularly limited, and examples thereof include acrylic particles, starch, beer lees, and walnut shells. These may be used alone or in combination of two or more.
As the pore former, acrylic particles are preferable, and spherical acrylic particles are more preferable.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, the particle diameter of the pore former is not particularly limited, but is preferably 20 to 100 μm, and more preferably 30 to 60 μm.
When used as a filter for purifying exhaust gas, a honeycomb structure having excellent performance as a filter can be produced.
If the pore diameter is less than 20 μm, a large amount of pore former is required in order to obtain pores having a necessary volume. As a result, since the organic content derived from the pore former is increased, a large amount of heat is generated at the time of degreasing, and the honeycomb degreased body is easily broken. On the other hand, when the particle diameter of the pore former exceeds 100 μm, the pores are easily distributed and not dispersed. As a result, a portion where the mechanical strength is locally weakened is generated, so that the strength of the honeycomb sintered body after the reaction step tends to decrease.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the content of the pore former in the wet mixture is preferably 20 to 60% by weight, and more preferably 30 to 50% by weight.
A honeycomb sintered body having a high porosity and sufficient strength can be obtained.
When the content of the pore former in the wet mixture is less than 20% by weight, it becomes difficult to obtain a honeycomb sintered body having a high porosity. On the other hand, if the content of the pore former in the wet mixture exceeds 60% by weight, the content of silicon carbide constituting the honeycomb sintered body after the reaction step becomes too small, so that the strength of the honeycomb sintered body is sufficient. It becomes difficult to obtain.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the organic binder contained in the wet mixture is not particularly limited, and examples thereof include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and polyethylene glycol. Of these, methylcellulose is desirable. It is preferable that the compounding quantity of an organic binder is 1-10 weight part normally with respect to 100 weight part of the powder and pore former containing a carbon particle.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, the wet mixture may contain at least one of a plasticizer and a lubricant.
It does not specifically limit as a plasticizer, For example, glycerol etc. are mentioned.
The lubricant is not particularly limited, and examples thereof include polyoxyalkylene compounds such as polyoxyethylene alkyl ether and polyoxypropylene alkyl ether.
Specific examples of the lubricant include polyoxyethylene monobutyl ether and polyoxypropylene monobutyl ether.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, when preparing a wet mixture, a dispersion medium liquid may be used. Examples of the dispersion medium liquid include water, an organic solvent such as benzene, Examples thereof include alcohols such as methanol.
Furthermore, a molding aid may be added to the wet mixture.
The molding aid is not particularly limited, and examples thereof include ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol and the like.

Examples of the inorganic binder contained in the adhesive paste and the outer periphery coating material paste include silica sol and alumina sol. These may be used alone or in combination of two or more. Among inorganic binders, silica sol is desirable.

Examples of the organic binder contained in the adhesive paste and the outer periphery coating material paste include polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and the like. These may be used alone or in combination of two or more. Among organic binders, carboxymethylcellulose is desirable.

Examples of the inorganic particles contained in the adhesive paste and the outer periphery coating material paste include carbide particles and nitride particles. Specific examples include silicon carbide particles, silicon nitride particles, and boron nitride particles. These may be used alone or in combination of two or more. Among the inorganic particles, silicon carbide particles having excellent thermal conductivity are desirable.

Examples of the inorganic fibers and / or whiskers contained in the adhesive paste and the outer periphery coating material paste include inorganic fibers and / or whiskers made of silica-alumina, mullite, alumina, silica, and the like. These may be used alone or in combination of two or more. Among inorganic fibers, alumina fibers are desirable. The inorganic fiber may be a biosoluble fiber.

Furthermore, pore forming agents such as balloons, spherical acrylic particles, and graphite, which are fine hollow spheres containing oxide ceramics, may be added to the adhesive paste and the outer periphery coating material paste as necessary. The balloon is not particularly limited, and examples thereof include an alumina balloon, a glass micro balloon, a shirasu balloon, a fly ash balloon (FA balloon), and a mullite balloon. Of these, alumina balloons are preferred.

In the method for manufacturing a honeycomb structured body according to the embodiment of the present invention, a catalyst for purifying exhaust gas may be supported on the cell walls of the honeycomb sintered body constituting the manufactured honeycomb structured body.
As the catalyst to be supported, for example, a noble metal such as platinum, palladium, or rhodium is desirable. As other catalysts, for example, alkali metals such as potassium and sodium, alkaline earth metals such as barium, zeolite, and the like can be used. These catalysts may be used alone or in combination of two or more.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the shape of the honeycomb structure to be manufactured is not limited to a columnar shape, but an arbitrary column shape such as an elliptical column shape, a long column shape, or a polygonal column shape. If it is.

Further, in the method for manufacturing a honeycomb structure according to the embodiment of the present invention, when the manufactured honeycomb structure is used as a filter, the average pore diameter of the honeycomb sintered body constituting the honeycomb structure is 5 to 30 μm. It is desirable that
When the average pore diameter of the honeycomb sintered body is less than 5 μm, the honeycomb sintered body is likely to be clogged. On the other hand, when the average pore diameter of the honeycomb sintered body exceeds 30 μm, the particulates pass through the pores of the honeycomb sintered body, and the honeycomb sintered body cannot collect the particulates. It cannot function as a filter.
The pore diameter can be measured by a mercury intrusion method that is a conventionally known method.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the cell density in the cross section of the honeycomb sintered body constituting the honeycomb structure to be manufactured is not particularly limited, but a desirable lower limit is 31.0 cells / cm ^2. (200 / inch ² ), desirable upper limit is 93.0 / cm ² (600 / inch ² ), more desirable lower limit is 38.8 / cm ² (250 / inch ² ), more desirable upper limit Is 77.5 / cm ² (500 / inch ² ).

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the thickness of the cell wall of the honeycomb sintered body constituting the honeycomb structure to be manufactured is not particularly limited, but is 0.1 to 0.00. 4 mm is desirable.
If the cell wall thickness is less than 0.1 mm, the cell wall thickness becomes too thin, and the strength of the honeycomb sintered body cannot be maintained. On the other hand, when the thickness of the cell wall exceeds 0.4 mm, the pressure loss of the honeycomb structure tends to increase.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the thickness of the outer peripheral wall of the honeycomb sintered body constituting the honeycomb structure to be manufactured may be the same as the thickness of the cell wall. However, from the viewpoint of the strength of the honeycomb sintered body, it is desirable that the thickness be larger than the cell wall thickness.
When the thickness of the outer peripheral wall of the honeycomb sintered body is larger than the thickness of the cell wall, the thickness of the outer peripheral wall is desirably 1.3 to 3.0 times the thickness of the cell wall.

In the method for manufacturing a honeycomb structure according to the embodiment of the present invention, the shape of the cross section perpendicular to the longitudinal direction of the honeycomb sintered body of each cell of the honeycomb sintered body constituting the honeycomb structure to be manufactured is particularly limited. For example, any shape such as a circle, an ellipse, a quadrangle, a pentagon, a hexagon, a trapezoid, and an octagon may be used. Various shapes may be mixed.

In the method for manufacturing a honeycomb structured body of the present invention, a honeycomb formed body preparing step for preparing a honeycomb formed body including carbon particles and in which a large number of cells are arranged in parallel in the longitudinal direction with a cell wall therebetween, and the honeycomb formed body described above In addition, a reaction step for producing a porous silicon carbide honeycomb sintered body by reacting molten silicon is an essential component. Moreover, in the honeycomb structure of the present invention, it is an essential component that the honeycomb structure is manufactured by the method for manufacturing a honeycomb structure of the present invention.
The essential components include various configurations detailed in the first embodiment of the present invention and the other embodiments (for example, types and contents of powders containing carbon particles, types and contents of pore formers). The desired effect can be obtained by appropriately combining the presence / absence and conditions of the sealing step, the presence / absence and conditions of the degreasing step, and the conditions of the reaction step.

10 honeycomb formed body 11, 111, 211 cell 12, 112, 212 cell wall 13, 113 outer peripheral wall 100, 200 honeycomb structure 101 adhesive layer 102, 202 outer peripheral coat layer 103, 203 ceramic block 110 honeycomb sintered body 114, 214 Sealant G Exhaust gas

Claims (8)

A honeycomb formed body preparing step of preparing a honeycomb formed body including carbon particles and having a number of cells arranged in parallel in the longitudinal direction across the cell wall;
A degreasing step of degreasing the honeycomb formed body;
After the degreasing step, by reacting the carbon particles and the molten silicon, we saw including a reaction step of preparing a porous silicon carbide honeycomb sintered body,
The method for manufacturing a honeycomb structure , wherein the carbon particles include two or more kinds of particles having different average particle diameters and include amorphous coke having an average particle diameter of 10 to 20 μm . The method for manufacturing a honeycomb structure according to claim 1 , wherein the carbon particles include carbon black having an average particle diameter of 40 to 80 nm. The carbon particles, and the amorphous coke, a method for manufacturing a honeycomb structure according to claim 1 comprising a carbon black having a smaller average particle diameter than the average particle diameter of the amorphous coke. Wherein in the reaction step, the method for manufacturing a honeycomb structure according to any one of claims 1 to 3 for impregnating the molten silicon in the honeycomb molded body. Wherein in the honeycomb formed body preparing step, the method for manufacturing a honeycomb structure according to any one of claims 1 to 3 for preparing a honeycomb molded body containing the carbon particles and silicon particles. In the reaction step, the method for manufacturing a honeycomb structure according to claim 4 or 5, melting the silicon by flux of an alkali metal. The method for manufacturing a honeycomb structured body according to claim 6 , wherein the alkali metal is sodium. The honeycomb structure according to any one of claims 1 to 7 , further comprising a sealing step of filling a sealing material paste so that any one end of the cells of the honeycomb formed body is sealed. Production method.