JP2013087034A - Method for producing ceramic bonded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a ceramic bonded body in which a ceramic porous body is hardly exfoliated from a ceramic base material and which is excellent in quality stability.SOLUTION: The method for producing the ceramic bonded body 30, in which the ceramic porous body 10 is bonded to the surface of the ceramic base material 20, comprises the steps of: preparing a composition for forming the ceramic porous body, in which the composition contains at least ceramic powder, an organic binder, a water-insoluble organic solvent and water, in which the content of the water in the composition accounts for 1-50 mass% to the total mass of the ceramic powder, the organic binder and the water-insoluble organic solvent; coating the surface of the ceramic base material 20 with the composition; and firing the coated composition to obtain the ceramic bonded body 30 in which the ceramic porous body 10 is bonded to the surface of the ceramic base material 20.

Description

  The present invention relates to a method for producing a ceramic joined body, and a ceramic porous body forming composition used in the production method.

  A ceramic porous body having pores with a large pore diameter (for example, 50 μm or more) is superior in heat resistance and corrosion resistance to resin materials such as plastics and metal materials. Therefore, industrial grindstones, industrial ceramic molds, refractories It is preferably used as a member constituting a setter for firing. In recent years, since liquid or gas permeability is high, it is expected to be used as a functional ceramic member such as a porous substrate for fuel cells, a ceramic filter, and a catalyst carrier.

  Conventionally, in the production of a ceramic porous body, a large amount of pore forming material (for example, carbon) that burns down at high temperature is added to ceramic powder, and after molding into a required shape, the pore forming material is burned off by firing treatment. A method of forming pores is used. There is also a method in which the gap between the raw material powders remains as pores by press-molding ceramic powder at a low density without using a pore-forming material and sintering and solidifying the molded body. Among these, since it is the simplest and inexpensive, a method of forming a low-density molded body of ceramic powder and leaving the particle gaps as pores is often employed. Patent documents 1-6 are mentioned as conventional technology about this kind of ceramic porous body.

Japanese Patent Application Laid-Open No. 06-1673 JP 07-215777 A JP 2006-282419 A Japanese Patent Laid-Open No. 08-12463 JP 09-71482 A JP 09-87704 A

  By the way, a ceramic porous body having pores with a large pore diameter (for example, 50 μm or more) is inferior in mechanical strength to dense ceramics or small pore ceramic porous bodies. It is used after being raised. In order to further improve the strength, the ceramic porous body is often used by being joined (integrated) with a dense or different kind of porous ceramic base material having a relatively small pore diameter. As a method for integrating the ceramic porous body and the ceramic base material, for example, a method of integrally sintering the ceramic porous body and the ceramic base material by firing is used.

  However, when a ceramic porous body having a large pore diameter (for example, 50 μm or more) as described above is to be joined (integrated sintering) on the same kind or different kind of porous ceramic substrate having a relatively small or small pore diameter, Since the pore diameters (and hence the firing shrinkage ratio) of the two are greatly different, the bondability tends to deteriorate. Therefore, there is a problem that the strength of the bonded portion after sintering tends to be low, and the bonded portion easily peels off with a small force. Insufficient strength at the joint is not preferable because it cannot be put into practical use (for example, industrial grindstones, ceramic filters, etc.) where the joint is required to have pressure resistance or load resistance.

  The present invention has been made in view of the above points, and the main object of the present invention is to provide a ceramic joint capable of producing a ceramic joined body having excellent quality stability in which the ceramic porous body and the ceramic base material are not easily separated. It is to provide a body manufacturing method. Another object of the present invention is to provide a composition for forming a porous ceramic body that is suitably used for producing such a ceramic joined body.

  According to the present invention, there is provided a method for producing a ceramic joined body (laminated body) in which a ceramic porous body is joined to the surface of a ceramic substrate. This manufacturing method includes preparing a ceramic porous body-forming composition containing at least a ceramic powder, an organic binder, a water-insoluble organic solvent, and water. Here, the content of water in the composition is an amount corresponding to 1% by mass to 50% by mass with respect to the total mass of the ceramic powder, the binder, and the water-insoluble organic solvent. The manufacturing method also includes applying the composition to the surface of a ceramic substrate. Then, the coated product is fired to obtain a ceramic joined body in which a ceramic porous body is joined (sintered integrally) to the surface of the ceramic substrate.

  According to the production method of the present invention, when a composition for forming a porous ceramic body containing a water-insoluble organic solvent and water is used, the composition is applied to a ceramic base material to be bonded. In addition, the composition is easily adapted to the ceramic substrate. For this reason, the adhesion of the ceramic porous body obtained after firing to the ceramic base material (joining strength contributed by the anchor effect or the like) is improved, and the ceramic porous body and the ceramic base material can be firmly joined. Therefore, according to the present invention, the ceramic porous body and the ceramic base material are difficult to be peeled off, and the ceramic is excellent in quality stability (for example, the peeling between the ceramic porous body and the ceramic base material can be prevented for a longer time). A joined body can be manufactured.

  The content of water in the composition is generally about 1% by mass or more, preferably 5% by mass or more, particularly preferably based on the total mass of the ceramic powder, the binder, and the water-insoluble organic solvent. Is 20% by mass or more. By using the composition having such a water content, a ceramic porous body having extremely high adhesion to the ceramic substrate can be formed. If the water content is too low, the adhesion between the ceramic porous body and the ceramic substrate (bonding strength contributed by the anchor effect, etc.) will be insufficient, and the ceramic porous body will partially lift or peel off from the ceramic substrate. It may be easier. On the other hand, if the content of water is too large, the organic solvent and water are phase-separated, and thus the above-described effects may not be exhibited properly.

  In a preferred embodiment disclosed herein, the mixing ratio of the water-insoluble organic solvent and the water in the composition is preferably in the range of organic solvent: water = 95: 5 to 30:70 by mass ratio, 90:10 to 40:60 is more preferable, and 80:20 to 50:50 is particularly preferable. When the amount of water is less than organic solvent: water = 95: 5, the performance improvement effect (adhesion improvement effect between the ceramic porous body and the ceramic base material) due to the inclusion of water may be insufficient, When the amount of water is larger than organic solvent: water = 30: 70, the organic solvent and water are phase-separated, and thus the above-described effects may not be exhibited properly.

  In a preferred embodiment of the method for producing a ceramic joined body disclosed herein, an average pore diameter based on a mercury intrusion method of the ceramic porous body is 50 μm to 200 μm. Regarding the improvement of the bonding strength between the ceramic porous body and the ceramic substrate by using the ceramic porous body forming composition disclosed herein, the ceramic porous body having a large pore diameter (for example, 50 μm or more) as described above is ceramic. This is particularly effective when joining (integrated sintering) on a substrate.

  In a preferred embodiment of the method for producing a ceramic joined body disclosed herein, the ceramic substrate is dense or porous ceramic having an average pore diameter relatively smaller than that of the ceramic porous body (for example, an average pore diameter of 1 μm or less). It is a substrate. Regarding the improvement of the bonding strength between the ceramic porous body and the ceramic base material by using the ceramic porous body forming composition disclosed herein, the porous ceramic base material as described above is relatively dense or has a relatively small pore diameter. On the other hand, it can be exhibited particularly effectively when the ceramic porous body having the large pore diameter (for example, 50 μm or more) as described above is joined (integrated sintering).

  In a preferred aspect of the ceramic joined body manufacturing method disclosed herein, the ceramic base material and the ceramic porous body are made of the same kind of material. By using such a ceramic substrate made of the same type of material, the anchor effect is more reliably exhibited between the ceramic porous body and the ceramic substrate, and sufficient bonding strength can be ensured.

  In a preferred embodiment of the method for producing a ceramic joined body disclosed herein, the coated product is fired such that the maximum firing temperature is 600 ° C to 900 ° C. As a result, a ceramic joined body in which the ceramic porous body and the ceramic base material are strongly integrally sintered (joined) can be obtained. Therefore, required durability is ensured for the ceramic joined body, and the performance of the ceramic joined body is stabilized.

  In a preferred embodiment of the method for producing a ceramic joined body disclosed herein, the average thickness of the ceramic porous body is 100 μm or more. While the configuration in which the ceramic porous body is formed into a thick film of 100 μm or more is advantageous for increasing the mechanical strength and durability of the ceramic porous body, when attempting to form the ceramic porous body into a thick film of 100 μm or more, Adhesion between the ceramic porous body and the ceramic base material (bonding strength contributed by the anchor effect or the like) may be insufficient, and the ceramic porous body may partially float or peel off from the ceramic base material. According to the manufacturing method disclosed herein, even when the ceramic porous body is formed into a thick film of 100 μm or more as described above, the ceramic porous body and the ceramic base material can be firmly bonded. Peeling from the ceramic substrate can be prevented for a longer time.

  In a preferred embodiment of the method for producing a ceramic joined body disclosed herein, the coating of the composition is performed by intaglio printing. If an attempt is made to form a ceramic porous body on a ceramic substrate using intaglio printing, the adhesion between the ceramic porous body and the ceramic substrate is weak, and the ceramic porous body tends to peel off from the ceramic substrate. It is particularly useful to apply the invention.

  According to the present invention, there is also provided a ceramic porous body-forming composition that is suitably used in the method for producing a ceramic joined body disclosed herein. That is, it is a composition for forming a porous ceramic body that is used by being applied to the surface of a ceramic substrate, and contains at least ceramic powder, an organic binder, and water in a water-insoluble organic solvent. And the content of the water is an amount corresponding to 1% by mass to 50% by mass with respect to the total mass of the ceramic powder, the binder, and the water-insoluble organic solvent. By using such a composition for forming a ceramic porous body, a ceramic porous body that is firmly bonded (integrated and sintered) to the surface of the ceramic substrate can be formed. Therefore, it is possible to produce a ceramic joined body that is difficult to peel off from the ceramic porous body and the ceramic base material and has excellent quality stability.

  In a preferred embodiment of the ceramic porous body forming composition disclosed herein, the ceramic powder has an average particle size based on a laser scattering method of 50 μm or more (for example, 50 μm to 200 μm). By using ceramic powder having an average particle size of 50 μm or more, gaps between the powders can be effectively left as pores even after firing. For this reason, the pore diameter and porosity of the ceramic porous body can be increased more effectively. The material of the ceramic powder is not particularly limited, and various ceramic powders such as metal oxides, carbides, and nitrides can be employed. For example, a ceramic powder mainly composed of alumina or silica can be preferably used. “Mainly” as used herein means that 50% by mass or more (preferably 75% by mass or more, more preferably 80% by mass to 100% by mass) of the entire ceramic powder is alumina or silica.

  As the water-insoluble organic solvent used in the composition disclosed herein, any organic solvent may be used as long as it is insoluble or hardly soluble in water, but the ceramic powder and the organic binder are well dispersed. It is preferable that they can be mixed. From the viewpoint of suppressing the compatibility with water, the solubility in water at 25 ° C. is preferably 15 (g / 100 ml) or less, and preferably 10 (g / 100 ml) or less. Particularly preferred. Examples of such an organic solvent include 4 carbon atoms such as isobutyl alcohol (IBA), 1-butanol, 2-butanol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, and the like. The above-mentioned (preferably 4-10) alcohol solvent is mentioned.

It is sectional drawing which shows typically the ceramic joined body which concerns on one Embodiment of this invention. It is a figure which shows the manufacture flow of the ceramic joined body manufacturing method which concerns on one Embodiment of this invention. It is a SEM image which shows the peeling surface of the ceramic joined body which concerns on one test example of this invention. It is a SEM image which shows the peeling surface of the ceramic joined body which concerns on one test example of this invention. It is a SEM image which shows the peeling surface of the ceramic joined body which concerns on one test example of this invention.

  Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than matters particularly mentioned in the present specification (for example, a method for producing a ceramic joined body and a composition for forming a ceramic porous body used in the production method) and matters necessary for carrying out the present invention (Such as a method for synthesizing the ceramic raw material powder) can be grasped as a design matter of those skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  The ceramic joined body according to the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing a ceramic joined body 30. As shown in FIG. 1, the ceramic joined body 30 according to the present embodiment is formed by integrally sintering (joining) the ceramic porous body 10 and a predetermined ceramic base material 20 by firing.

  Any material that can be used to form the ceramic porous body 10 can be used without particular limitation as long as it is conventionally used to produce a ceramic porous body by sintering. For example, various ceramic powders such as metal oxides, carbides, and nitrides can be employed. For example, ceramic materials such as α-alumina, γ-alumina, silica, zirconia, silicon nitride, silicon carbide, titania, calcia, and various zeolites can be preferably used. Moreover, the ceramic material formed from these composites or a mixture may be sufficient.

  The porosity of the ceramic porous body 10 based on the mercury intrusion method is generally in the range of 10% to 60%, and preferably in the range of 30% to 40%. The average pore diameter (based on the mercury intrusion method) is generally in the range of 50 μm to 200 μm, preferably 60 μm to 150 μm, particularly preferably 80 μm to 120 μm. Such a ceramic porous body having a large pore diameter and a large porosity can be suitably used for applications such as industrial grindstones and ceramic filters. Although the thickness of the ceramic porous body 10 can be determined as appropriate according to the application, it is generally about 100 μm to 1000 μm, preferably 100 μm to 500 μm, and particularly preferably 100 μm to 400 μm. When the thickness of the ceramic porous body 10 is within the predetermined range, the mechanical strength and durability of the ceramic porous body 10 can be sufficiently secured.

  Any material that can be used to form the ceramic substrate 20 can be used without particular limitation as long as it has been conventionally used for joining (integrated sintering) to a ceramic porous body by sintering. For example, ceramic materials such as α-alumina, γ-alumina, silica, zirconia, silicon nitride, silicon carbide, titania, calcia, and various zeolites can be preferably used. Moreover, the ceramic material formed from these composites or a mixture may be sufficient. From the viewpoint of improving the bonding property with the ceramic porous body 10, it is desirable that the material is the same type as the ceramic porous body.

  The ceramic substrate 20 may be dense or porous, but the pore diameter of the ceramic substrate 20 is preferably smaller than the pore diameter of the ceramic porous body 10. For example, it is preferable to use a ceramic substrate having an average pore size of 10 μm or less (for example, 0.1 μm to 10 μm), more preferably 5 μm or less (for example, 0.1 μm to 5 μm), and particularly preferably 1 μm or less (for example, 0.1 μm or less). 1 μm to 1 μm). The porosity is generally 20% or less, preferably 5% or less. By bonding the ceramic porous body 10 having the large pore diameter (for example, 50 μm or more) as described above to the ceramic base material 20 having a relatively small pore diameter and porosity, the mechanical strength of the ceramic porous body 10 is increased. Can be reinforced. Therefore, in applications such as ceramic structural materials and functional ceramics, it can be suitably used as a highly porous member.

  Subsequently, with reference to FIG. 2, a method for manufacturing the ceramic joined body 30 according to the present embodiment will be described. FIG. 2 is a diagram showing a manufacturing flow of the ceramic joined body 30.

  As shown in FIG. 2, the ceramic joined body 30 according to the present embodiment can be manufactured through a composition preparation step (step S10), a coating step (step S20), and a firing step (step S30). The composition preparation step includes preparing a ceramic porous body forming composition containing at least a ceramic powder, an organic binder, a water-insoluble organic solvent, and water. Here, the content of water in the composition is an amount corresponding to 1% by mass to 50% by mass with respect to the total mass of the ceramic powder, the binder, and the water-insoluble organic solvent. In addition, the coating step includes coating the composition on the surface of the ceramic substrate. Further, the firing step includes firing the coated material to obtain a ceramic joined body in which a ceramic porous body is joined (integratedly sintered) to the surface of the ceramic substrate. Hereinafter, each process will be described in detail.

<Composition preparation process>
In the composition preparation step, a ceramic porous body forming composition is prepared in which at least ceramic powder, an organic binder, and water are dispersed in a water-insoluble organic solvent.

<Ceramic powder>
As the ceramic powder to be used, the powder made of the material constituting the ceramic porous body 10 described above can be used without particular limitation. The shape (outer shape) of the ceramic powder to be used is not particularly limited, and not only a spherical shape or a shape close thereto, but also a powder that is an aggregate of irregularly shaped particles prepared by, for example, roll milling or stamp milling is also preferably used. can do. From the viewpoint of suppressing densification (migration of ceramic particles) during firing, an irregularly shaped (for example, needle-like or plate-like) ceramic powder can be preferably used.

  As such ceramic powder, those having an average particle diameter (based on the laser scattering method) of approximately 50 μm to 200 μm are suitable, those having an average particle diameter of 50 μm to 150 μm are suitable, and those having an average particle diameter of 60 μm to 120 μm. Are more preferable, and those having a thickness of 80 μm to 100 μm are particularly preferable. By using ceramic powder having an average particle size of 50 μm or more, gaps between the powders can be effectively left as pores even after firing. For this reason, a ceramic porous body rich in pores having a pore size suitable for applications of ceramic structural materials (for example, industrial grindstones) and functional ceramics (for example, porous substrates for fuel cells, ceramic filters, catalyst carriers) is manufactured. Can do. On the other hand, if the average particle size is too larger than 200 μm, the pore size and porosity of the produced ceramic porous body will be too large, and the mechanical strength and durability may tend to decrease. From the viewpoint of achieving both high porosity and mechanical strength, approximately 50 μm to 200 μm (preferably 50 μm to 100 μm) is appropriate. The ratio of the ceramic powder in the composition is generally 10% by mass to 90% by mass, and preferably 50% by mass to 80% by mass.

<Organic binder>
The organic binder is for bonding the ceramic powder to maintain the shape, and the material constituting the organic binder is the same material as that used for manufacturing a conventionally known ceramic porous body. obtain. For example, cellulose resins such as ethyl cellulose and nitrocellulose, and acrylic resins such as methyl methacrylate are used. Alternatively, homopolymers or copolymers such as polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, and cellulose may be used. Among these, in consideration of decomposition and volatility in the firing step, it is more preferable to use a cellulose binder such as ethyl cellulose. These binders may be used alone or in combination of two or more. As a ratio of the binder in the said composition, it is 0.1 mass%-5 mass% in general, Preferably it is 0.5 mass%-1.5 mass%.

<Water-insoluble organic solvent>
As the water-insoluble organic solvent, any organic solvent may be used as long as it is insoluble or hardly soluble in water. However, the ceramic powder and the organic binder described above can be well dispersed and mixed. It is preferable. From the viewpoint of appropriately suppressing the compatibility between the organic solvent and water, the solubility in water at 25 ° C. is preferably 15 (g / 100 ml) or less, and preferably 10 (g / 100 ml) or less. It is particularly preferable that Examples of such organic solvents include isobutyl alcohol (IBA), 1-butanol, 2-butanol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, and the like having 4 or more carbon atoms ( Preferably, an alcohol solvent of 4 to 10) is used. Of these, the use of isobutyl alcohol (IBA) is preferred. Or, aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene, xylene, diethylbenzene, and styrene, aliphatic hydrocarbon solvents such as hexane, heptane, and octane, and ether solvents such as dimethyl ether, diethyl ether, and methyl ethyl ether. It can also be used. These organic solvents may be used individually by 1 type, and may be used in combination of 2 or more types. When using in combination of 2 or more types, it is preferable that a liquid mixture forms a single continuous phase. The proportion of the water-insoluble organic solvent in the composition is generally 50% by mass to 95% by mass, and preferably 75% by mass to 95% by mass.

<Water content>
The composition for forming a ceramic porous body according to the present embodiment further contains a predetermined amount of water in addition to the above-described ceramic powder, organic binder, and water-insoluble organic solvent. The content of water in the composition is appropriately about 1% by mass to 50% by mass, preferably 5% by mass with respect to the total mass of the ceramic powder, the binder and the water-insoluble organic solvent. % To 50% by mass, particularly preferably 20% to 50% by mass. According to the composition having such a water content, when the composition is applied to the ceramic substrate, the composition is easily adapted to the ceramic substrate, so that the ceramic porous body obtained after firing adheres to the ceramic substrate. (Bonding strength contributed by anchor effect and the like) can be improved. If the water content is too low, the adhesion between the ceramic porous body and the ceramic substrate (bonding strength contributed by the anchor effect, etc.) will be insufficient, and the ceramic porous body will partially lift or peel off from the ceramic substrate. It may be easier. On the other hand, if the content of water is too large, the organic solvent and water are phase-separated, and thus the above-described effects may not be exhibited properly. From the viewpoint of suppressing phase separation between the organic solvent and water, the water content is generally 50% by mass or less, preferably 40% by mass or less, and particularly preferably 25% by mass or less.

  In a preferred embodiment disclosed herein, the mixing ratio of the water-insoluble organic solvent and water in the composition is preferably in the range of organic solvent: water = 95: 5 to 30:70 by mass ratio, 90: 10:40:60 is more preferable, and 80: 20-50: 50 is particularly preferable. When the amount of water is less than organic solvent: water = 95: 5, the performance improvement effect (adhesion improvement effect between the ceramic porous body and the ceramic base material) due to the inclusion of water may be insufficient, When the amount of water is larger than organic solvent: water = 30: 70, the organic solvent and water are phase-separated, and thus the above-described effects may not be exhibited properly.

<Other ingredients>
The ceramic porous body-forming composition is used in the production of general ceramic porous bodies in addition to the above-described ceramic powder, organic binder, water-insoluble organic solvent, and water as long as the effects of the present invention are exhibited. One or more materials that can be made can be included as required. For example, for the purpose of stabilizing the porous structure, various sintering aids, plasticizers, dispersants, etc., or any conventionally known additive can be added as appropriate.

<Kneading>
These various components can be mixed (kneaded) using a general kneading means such as a ball mill, a homodisper, a jet mill, an ultrasonic disperser, or a planetary mixer. Although not particularly limited, when mixing ceramic powder, organic binder, water-insoluble organic solvent and water, first mix the ceramic powder, organic binder and water-insoluble organic solvent before adding water. And knead well using a ball mill or the like. Next, it is preferable to add water to the obtained kneaded product and knead again. By adding water in this way, it is possible to prepare a ceramic porous body forming composition in which ceramic powder, a binder, and water are uniformly dispersed. Preferably, the kneading conditions (kneading speed, kneading time, etc.) are set so that the kneaded product becomes clouded (emulsified).

<Coating process>
When the composition for forming a ceramic porous body is thus prepared, the composition is applied to the surface of the ceramic substrate. The operation of applying the composition to the surface of the ceramic substrate can be used without any particular limitation on conventional general coating means and ceramic material forming means. For example, it can be applied by applying an appropriate coating means (for example, intaglio printing method) and coating a predetermined amount of the composition to a uniform thickness on one surface of the ceramic substrate. At that time, by using a ceramic porous body-forming composition containing a water-insoluble organic solvent and water, the composition can be easily adapted to the ceramic substrate when the composition is applied to the ceramic substrate. Become. Therefore, the composition can be stably applied to a uniform thickness without being repelled on the surface of the ceramic substrate. Other known coating means include a metal mask printing method, a screen printing method, a dip coating method, a spin coating method, a doctor blade method, and the like, and these can also be applied.

<Baking process>
When the composition is applied to the surface of the ceramic substrate in this way, the coated material is fired in the air, and the ceramic porous body is bonded (integrated sintered) to the surface of the ceramic substrate. A body is obtained (step S30). In the method for manufacturing a ceramic joined body disclosed herein, the coated product is fired so that the maximum firing temperature is 600 ° C to 900 ° C. As a result, a ceramic joined body in which the ceramic porous body and the ceramic base material are strongly integrally sintered (joined) can be obtained. Therefore, required durability is ensured for the ceramic joined body, and the performance of the ceramic joined body is stabilized.

  The maximum firing temperature at the time of the firing may be determined in the range of, for example, 600 ° C to 900 ° C (preferably 600 ° C to 800 ° C, more preferably 600 ° C to 700 ° C). If the firing temperature is too high or too low than such a range, it becomes difficult to obtain a ceramic joined body that satisfies the above characteristics. The time for maintaining the firing temperature (maximum firing temperature) depends on the firing temperature, but is generally about 0.5 to 2 hours, preferably about 1 to 1.5 hours. When the holding time is longer than the above range, it becomes difficult to obtain a ceramic joined body that satisfies the above characteristics. For example, the average pore size tends to be smaller than the desired size or the pore size distribution tends to be broad. The atmosphere in which the firing is performed is not limited to the air atmosphere described above, and may be an oxygen atmosphere richer in oxygen than the air, a nitrogen gas atmosphere, an inert gas atmosphere, or the like as necessary.

  Thus, the ceramic joined body 30 in which the ceramic porous body 10 and the ceramic base material 20 are integrally sintered (joined) can be obtained. According to the method for producing a ceramic joined body of the present embodiment, the composition is applied to the ceramic substrate 20 by using a ceramic porous body forming composition containing a predetermined amount of water in a water-insoluble organic solvent. When processed, the composition is easily adapted to the ceramic substrate 20. Therefore, the adhesion (bonding strength contributed by the anchor effect) of the ceramic porous body 10 obtained after firing to the ceramic base material 20 is improved, and the ceramic porous body 10 is lifted or peeled off from the ceramic base material 20. You can avoid the situation. Therefore, according to the present embodiment, the ceramic porous body 10 and the ceramic base material 20 are difficult to peel off and excellent in quality stability (for example, the ceramic porous body 10 and the ceramic base material 20 are peeled off for a longer time). The ceramic joined body 30 that can be prevented can be manufactured stably and easily.

  In practicing the present invention, the ceramic porous body 10 and the ceramic substrate are formed by using the ceramic porous body forming composition containing a predetermined amount of water in the water-insoluble organic solvent disclosed herein. Although it is not necessary to elucidate the mechanism for improving the adhesion (bonding strength) to 20, the following may be considered. That is, the ceramic substrate 20 has some OH groups due to hydration of a part of its surface. When a composition for forming a porous ceramic body in which water molecules are present in a water-insoluble organic solvent is applied to the surface of the ceramic substrate 20, the water molecules in the composition are OH groups present on the surface of the ceramic substrate 20. Therefore, the composition becomes easy to conform to the ceramic substrate 20. Therefore, it is considered that the adhesion between the ceramic porous body 10 obtained after firing and the ceramic base material 20 is improved, and the ceramic porous body 10 and the ceramic base material 20 can be joined more firmly.

  Since the ceramic joined body 30 obtained by any of the manufacturing methods disclosed herein can firmly join the ceramic porous body 10 and the ceramic base material 20, pressure resistance and load resistance are required at the joint. Applications such as industrial grindstones, industrial ceramic molds, refractories, firing setters, and other ceramic structural materials, ceramic filters, porous substrates for fuel cells, and functional ceramics such as catalyst carriers Can be. Accordingly, as one aspect of the present invention, ceramic structural materials (for example, industrial grindstones, industrial ceramic molds, refractories, firing setters, etc.) and functional ceramic porous members (for example, porous substrates for fuel cells, ceramic filters) Further, there are provided a method for producing a ceramic joined body suitably used as an application of a catalyst support and the like, and a ceramic joined body obtained by the method.

  Hereinafter, some examples relating to the present invention will be described, but the present invention is not intended to be limited to those shown in the examples.

<Production and evaluation of ceramic joined body>
[Sample 1]
Silica powder (ceramic powder) having an average particle size of 55 μm is mixed with a vehicle in which ethyl cellulose (EC) as a binder and isobutyl alcohol (IBA) as a water-insoluble organic solvent are mixed at a mass ratio of 9:91. Was added and kneaded so that the mass ratio of to the vehicle was 15: 5. A predetermined amount of water was added to the kneaded product and kneaded again to prepare a ceramic porous body-forming composition. The content of water in the composition was 5% by mass with respect to the total mass of EC, IBA, and silica powder (that is, by external addition). The obtained ceramic porous body-forming composition was intaglio-printed on the surface of a ceramic substrate (a porous alumina substrate having an average pore diameter of 0.1 μm and a thickness of about 0.5 mm), and a thickness of about A 100 μm coated product (thin film) was formed. The coated material was fired at about 600 ° C. in the atmosphere to obtain a ceramic joined body in which the ceramic porous body was integrally sintered (joined) on the ceramic substrate.

[Samples 2 to 5]
The content of water in the composition was 25% by mass (sample 2), 50% by mass (sample 3), 75% by mass (sample 4), and 0% by mass (sample 5; no addition of water). A ceramic joined body was produced in the same manner as in Sample 1 except that.

[Sample 6]
A ceramic joined body was produced in the same manner as in Sample 1 except that terpineol was added instead of water in the above composition.

[Sample 7]
A ceramic joined body was prepared in the same manner as in Sample 1 except that ethyl carbitol was added in place of water in the above composition.

  About the ceramic joined body of each obtained sample, the ceramic porous body was peeled off from the ceramic substrate. Then, the surface from which the ceramic porous body was peeled was observed with a scanning electron microscope (SEM), and the “bonded state” was evaluated according to the state of the bonded surface. The results are shown in Table 1. In Table 1, when the porous ceramic body is not peeled off from the ceramic base material and the uneven bonding surface is observed, the bonding state is good (O), and the porous ceramic body is peeled off from the ceramic base material smoothly and smooth. What the joining surface was observed was described as poor (x) in the joining state. Surface SEM images of the bonding surfaces of Samples 2, 5, and 6 are shown in FIGS.

  As is apparent from the results of Table 1 and FIGS. 3 to 5, the ceramic joined bodies of Samples 5 to 7 in which water was not added to the composition were smooth because the ceramic porous body was peeled cleanly from the ceramic substrate. A good bonding surface was observed. On the other hand, in the ceramic joined bodies of Samples 1 to 3 in which water was added to the composition, the porous ceramic body was not peeled off from the ceramic base material, and uneven joint surfaces were observed. From this, it was confirmed that the bonding strength between the ceramic porous body and the ceramic base material was improved by adding water to the composition. In addition, although water was added to the composition, the ceramic porous body of Example 4 in which the water content was 75% by mass was not suitable for production because water and IBA were phase-separated. From the viewpoint of suppressing phase separation, the content of water in the composition is desirably 50% by mass or less (preferably 25% by mass or less).

  From the above results, according to this test example, the bonding strength between the ceramic porous body and the ceramic base material is improved by using the ceramic porous body forming composition containing water in a water-insoluble organic solvent. I was able to. Therefore, according to this configuration, it is possible to realize a ceramic joined body having excellent quality stability in which the ceramic porous body and the ceramic base material are hardly separated.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

DESCRIPTION OF SYMBOLS 10 Ceramic porous body 20 Ceramic base material 30 Ceramic joined body

Claims (12)

A ceramic porous body forming composition used by coating on the surface of a ceramic substrate,
Contains at least ceramic powder, organic binder, water-insoluble organic solvent and water,
The composition for forming a ceramic porous body, wherein the water content is an amount corresponding to 1% by mass to 50% by mass with respect to a total mass of the ceramic powder, the binder, and the water-insoluble organic solvent.   The composition according to claim 1, wherein the water content is an amount corresponding to 5% by mass to 25% by mass with respect to a total mass of the ceramic particles, the binder, and the water-insoluble organic solvent.   The composition of Claim 1 or 2 whose mixing ratio of the said water-insoluble organic solvent and the said water is organic solvent: water = 95: 5-30: 70 by mass ratio.   The composition according to any one of claims 1 to 3, wherein the ceramic powder has an average particle size based on a laser scattering method of 50 µm to 200 µm.   The composition according to any one of claims 1 to 4, wherein the water-insoluble organic solvent is an alcohol solvent.   The composition according to claim 1, wherein the ceramic powder is mainly composed of alumina or silica. A method for producing a ceramic joined body in which a ceramic porous body is joined to a surface of a ceramic substrate,
Preparing a ceramic porous body-forming composition containing at least a ceramic powder, an organic binder, a water-insoluble organic solvent, and water, wherein the water content in the composition is the ceramic powder and the An amount corresponding to 1% by mass to 50% by mass with respect to the total mass of the binder and the water-insoluble organic solvent;
Applying the composition to the surface of a ceramic substrate; and
Firing the coated product to obtain a ceramic joined body in which a ceramic porous body is joined to the surface of the ceramic substrate;
A method for producing a ceramic joined body.   The manufacturing method of Claim 7 whose average pore diameter based on the mercury intrusion method of the said ceramic porous body is 50 micrometers-200 micrometers.   The manufacturing method according to claim 7 or 8, wherein the ceramic base material is a porous ceramic base material that is dense or has an average pore diameter relatively smaller than that of the ceramic porous body.   The manufacturing method as described in any one of Claims 7-9 whose thickness of the said ceramic porous body is 100 micrometers or more.   The manufacturing method according to claim 7, wherein the coating of the composition is performed by intaglio printing.   The manufacturing method according to any one of claims 7 to 11, wherein the baking of the coated product is performed such that a maximum baking temperature is 600 ° C to 900 ° C.