JP2001278672A - Method for manufacturing ceramic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic material whose element is easily changed into any shape and composition. SOLUTION: The method comprises conjugation, curing, drying, degreasing and sintering process. A curable ceramic slurry containing one or more kinds of ceramics is conjugated in the conjugation process. A conjugated slurry is cured in a wet form in the curing process. Then the cured material is dried, degreased and sintered in order in drying, degreasing and sintering process, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic material in which various elements of the ceramic are controlled, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, attempts have been made to control the pore size, porosity, pore structure, etc. of pores, which are one of the important elements of ceramic materials. For example, as a method of manufacturing a ceramic material capable of controlling these,
There are three methods below. The first method is a method in which a ceramic powder (on the order of μm) is incompletely fired to form a porous ceramic body having pores of the size of the powder. In this method, the firing is set at a low temperature and in a short time in a firing process for producing a dense body. According to this method, the pore diameter can be controlled to some extent by the powder size of the raw material. The pore size that can be controlled is
It is about μm at most.

A second method is a method of mixing an organic substance into a ceramic powder raw material or a ceramic slurry and removing the organic substance in a degreasing and firing process. In this method, the porosity can be controlled by the amount of the organic substance contained, and the pore diameter can be controlled to some extent by the size of the organic substance, but it is difficult to control the pore diameter distribution. The third method is a method in which a three-dimensional network structure is formed of an organic substance (generally a urethane resin), and a ceramic slurry is impregnated with the organic substance and fired to obtain a porous body.

[0004]

However, in these methods, the controllability of the form of pores, the formability, the strength of the obtained ceramic, and the like are not always sufficient. In recent years, in particular, by controlling various elements such as the composition, structure, pore structure, heat resistance, and heat conductivity of the ceramic material, the characteristics required by the application have been imparted, and a more practical ceramic material has been provided. Is being demanded. In particular, by controlling the above-mentioned various elements of the ceramic material and complexing the material, a material having a tilted function has been demanded. In addition, it is also required that a near net-shaped sintered body be obtained in order to exhibit functions according to the application.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for producing a ceramic material which can easily control the ceramic elements. It is another object of the present invention to provide a ceramic material in which the elements of the ceramic are highly controlled.

[0006]

Means for Solving the Problems The present inventors obtain an uncured laminate by laminating ceramic slurries having curability, and further cure the laminate to obtain a desired ceramic element. Have been found, and the present invention has been completed. That is, the present invention relates to a method of manufacturing a ceramic material, comprising the steps of: joining a ceramic slurry having curability; and curing the joined body of the ceramic slurry obtained in the step in a water-retaining state to cure water retention. A method comprising the steps of obtaining a body, drying this cured body, degreased dried cured body, and firing the degreased cured body is provided. According to this method, by the joining step,
Various shapes can be given to the joined body of the ceramic slurry. Further, by using two or more types of ceramic slurries capable of providing different ceramic elements, a joined body in which the ceramic elements are combined can be obtained. By curing these bonded bodies in a water-retaining state, a cured body in which the shape and element distribution of the bonded bodies are maintained is obtained, and as a result,
A fired body in which the shape and element distribution of the joined body are maintained can be obtained.

The present invention also relates to a method for producing a ceramic material, which comprises a step of bonding one or more ceramic slurries having a hardening ability and capable of imparting a change of a predetermined ceramic element to the ceramic material; The step of curing the joined body in a water-retentive state to obtain a water-retained cured body, the step of drying the cured body, the step of degreasing the dried cured body, and the step of firing the degreased cured body, Providing a method comprising: According to this manufacturing method, it is possible to obtain a joined body in which a desired ceramic element is continuously or intermittently changed by joining a ceramic slurry having a hardening ability so that a change in the ceramic element can be given, A ceramic material (fired body) in which the change of the ceramic element is maintained can be obtained.

In these inventions, when the ceramic slurry has air bubbles, a porous ceramic material can be obtained. Further, when the ceramic element has pores, a ceramic material having inclined pores can be obtained. Further, when using the bubble-containing ceramic slurry, the pores of the ceramic material are changed by using two or more kinds of ceramic slurries having different bubble-holding ability and / or a set curing time of the bubble-containing ceramic slurry. A ceramic material can be obtained.

In these methods, in the hardening step, a ceramic material having two or more areas having different ceramic elements can be obtained by applying different hardening conditions to two or more areas of the joined body. it can. In particular, when using a bubble-containing ceramic slurry, it is possible to obtain a ceramic material having two or more phases different in pore diameter and porosity (amount) by applying different curing conditions to two or more regions of the joined body. it can. Preferably, the two or more phases of the joined body each correspond to the joined slurry.

The present invention also provides a method for producing a ceramic material, which comprises firing a water-retentive cured body of a ceramic raw material in which the raw material composition and / or the particle diameter of the raw material continuously or intermittently change. Also, the raw material composition, the particle size of the raw material,
A method for producing a ceramic material, comprising firing at least one type of ceramic element selected from the group consisting of raw material particle form, pore diameter, and porosity, a water-retentive cured body of a ceramic raw material that changes continuously or intermittently. provide. According to these inventions, the raw material composition, the particle size of the raw material,
It is possible to obtain a ceramic material in which at least one of the particle morphology, pore diameter, and porosity of the raw material is inclined.

Further, the present invention provides a ceramic material obtained by firing a cured body of a ceramic raw material in which the raw material composition and / or the particle diameter of the raw material continuously or intermittently change. Further, two or more ceramic raw material phases in which at least one type of ceramic element selected from the group consisting of a raw material composition, a raw material particle diameter, a raw material particle form, a pore diameter, and a porosity are joined and fired. Provide ceramic materials. These ceramic materials can also have one or more boundaries at which the ceramic elements change.

[0012]

Embodiments of the present invention will be described below in detail. Any of the methods for manufacturing a ceramic material disclosed in the present specification, a ceramic slurry having curability is joined, cured in a state where moisture is held in the joined body, dried, degreased, and fired. Is the way. The ceramic material disclosed in the present specification is manufactured by the above-described method for manufacturing a ceramic material, and is a material having a desired shape and / or ceramic element distribution.

(Preparation Method of Ceramic Material) (Preparation of Ceramic Slurry Having Hardening Ability) The ceramic slurry contains a ceramic powder, a dispersion medium of the ceramic powder, and a component capable of imparting hardening ability to the slurry. . Further, preferably, a dispersant for uniformly dispersing the ceramic powder is contained.

The ceramic component of the ceramic powder is not particularly limited, and may be a known oxide or non-oxide ceramic or clay mineral.
More than one species can be used in combination. The form of the particles constituting the powder is not particularly limited. Examples of the oxide-based ceramics include alumina-based, mullite-based, and zirconia-based ceramics, and examples of the non-oxide-based ceramics include silicon carbide-based, silicon nitride-based, aluminum nitride-based, boron nitride-based, and graphite-based ceramics. Can be mentioned. An oxide ceramic is preferred, and an alumina is particularly preferred. The average particle size is not particularly limited, but is preferably 0.1 μm or more and less than 10 μm.
If a ceramic having an average particle size in this range is used, the dispersibility is good, and the strength of a sintered body obtained by sintering is easily 25 Mpa or more. The average particle size is more preferably 0.1 μm or more and 5 μm or less. More preferably, it is 0.1 μm or more and 1 μm or less, and most preferably 0.1 μm or more and 0.6 μm or less.

The dispersion medium of the ceramic powder is not particularly limited, and water, an organic solvent, a mixed solvent thereof or the like can be used. Preferably, it is water. As a dispersant,
Conventionally known various dispersants can be selected and used in consideration of the ceramic component and other components contained in the slurry. Typically, an ammonium polycarboxylate dispersant (anionic dispersant) can be used.

Examples of the component capable of imparting curability to the slurry include ordinary gelling agents and polymerizable materials including monomers and oligomers. When a gelling agent is used, the slurry can be hardened by temperature control, pH control, or the like. Examples of the gelling agent include known gelling agents such as starch, collagen, gelatin, agarose, agar, and natural or synthetic polymers such as sodium alginate. Such gelling agents can be used alone or in combination of two or more.

When a polymerizable material is used, the slurry can be hardened by polymerization of the monomer. In the case where a polymerizable material is used, a polymer formed by these materials is formed after curing. As the polymerizable material, a combination of a monomer or the like and a polymerization initiator or a curing agent capable of producing a synthetic resin curable in a water-retaining state can be selected from various known synthetic resin materials. For example, the polymerizable material may be a material containing a thermosetting resin such as an acrylic resin or a urethane resin, a thermoplastic resin such as polyethylene, polystyrene, or polyvinyl chloride, or a material containing a monomer capable of producing a photocurable resin. it can. In this case, preferably, the polymerization is a radical polymerization.

As the monomer of the polymerizable material, a monomer having one functional group or two or more functional groups can be exemplified. Preferably, a monomer having one or more vinyl groups or allyl groups can be used. In addition, 2
The functional monomer functions as a crosslinking agent. When the slurry is composed of water or an aqueous solvent, it is preferable to use a mono- or bifunctional polymerizable monomer. When the slurry is composed of an organic solvent, it is preferable to use a bifunctional polymerizable monomer. In particular, when the slurry is prepared using water as a solvent, preferably, at least one monofunctional acrylamide and at least one bifunctional acrylamide are used in combination. When the slurry is prepared with an organic solvent, preferably, at least two kinds of bifunctional acrylic acid are used in combination.

When using a polymerizable material,
The polymerization rate may change depending on the type and amount of the polymerization initiator. The polymerization initiator is usually inactive at room temperature in many cases, but it is not always necessary to use the polymerization initiator simultaneously with the monomer material to prepare a ceramic slurry. If necessary, it is added separately from the monomer. As the polymerization initiator, conventionally known various polymerization agents can be used. Which polymerization initiator is used is selected depending on the type of the monomer and how the curing is performed. When a monofunctional monomer or a bifunctional monomer is used, it is preferably ammonium persulfate or potassium persulfide. When a functional monomer having two or more functional groups is used, preferably, an organic peroxide, a hydrogen peroxide compound, or an azo or diazo compound is used. Preferably, it is benzoyl peroxide.

If a polymerization catalyst is added, the time of the curing step can be adjusted by the curing temperature and the amount added. Usually, when a polymerization catalyst is added, gelation (polymerization) is started immediately at around room temperature. Therefore, when it is desired to adjust the length of the curing step or when preparing a bubble-containing slurry, the use and type of the polymerization catalyst are selected as necessary.
Examples of the polymerization catalyst include N, N, N ', N'-tetramethylenediamine and the like.

The ceramic slurry includes a known lubricant,
Thickeners, sizing agents and the like can also be added. Examples of thickeners and sizing agents include methylcellulose, polyvinyl alcohol,
Saccharose, molasses, xanthan gum and the like can be exemplified.
Thickeners, sizing agents, and the like are suitable for stably holding the introduced bubbles when preparing a bubble-containing slurry, as described later. Further, a metal or ceramic fiber material or a metal or ceramic chip material which imparts properties such as strength to the obtained ceramic material can be added. Further, a trace amount of an inorganic compound which promotes sintering of the porous ceramic body can be added. In particular, when preparing a bubble-containing slurry, a surfactant can be added. The surfactant facilitates the introduction of air bubbles and retains the air bubbles. Also, a foaming agent can be added. The surfactant and the foaming agent will be described later.

The order of addition of each component of the ceramic slurry described above can be set as required. In particular, when preparing a ceramic slurry containing bubbles, it is preferable to add the gelling agent or the monomer material to the ceramic slurry before introducing the bubbles. Once
This is because if a hardening material is further added after the bubbles are introduced into the slurry, the bubbles may disappear or decrease. In addition, it is preferable to defoam the ceramic slurry which does not particularly contain bubbles before curing,
When adjusting the bubble-containing slurry, it is preferable to defoam the slurry before introducing the bubbles.

(Preparation of ceramic slurry containing bubbles)
Various methods can be employed to introduce bubbles into the ceramic slurry to obtain a bubble-containing ceramic slurry. Bubbles can be generated by a chemical reaction or the like. For example, this is a case where foaming conditions of a predetermined foaming agent (foaming agent) are given. As the foaming agent, a protein-based foaming agent, a surfactant-based foaming agent, and the like can be used. In addition, by stirring the slurry, blowing gas into the slurry, or the like, a gas can be introduced from the outside to introduce bubbles into the slurry. The method of introducing bubbles from the outside is preferable in that it is simple and the impurities in the slurry can be reduced as much as possible. When air bubbles are introduced from the outside, introduction of air bubbles is facilitated by adding a surfactant, and the introduced air bubbles can be stably held.

Examples of the surfactant include alkylbenzene sulfonic acid and higher alkyl amino acids. Specifically, dodecylbenzene sulfonic acid, polyoxyethylene sorbitan monolaurate, polyoxyethylene monooleate, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, and the like.

When a polymerizable material is used as the curing material, the slurry to which the monomer material has been added is used in advance.
It is preferable to add a polymerization initiator or a combination of a polymerization initiator and a polymerization catalyst during or after introducing bubbles. This is because when the curing is started, it is difficult to control the formation of bubbles.

Such a ceramic slurry or a bubble-containing ceramic slurry may be provided with a desired ceramic element change factor to be applied to a ceramic material finally obtained by joining the slurry. For example, when it is desired to change the ceramic composition, slurries having different ceramic compositions can be prepared. Here, different compositions include the case where the same raw material is used but the mixing ratio is different, and the case where the combination of raw materials is different. Further, when the combination of raw materials is different, it means that at least one kind of raw material is different. Therefore, a case where some raw materials match, a case where completely different raw materials are used, and the like are included. When the compositions are different, it is preferable that the compositions be such that the thermal expansion coefficients of the fired ceramic materials obtained based on the respective compositions are close to each other. This is to ensure the integrity after firing. In addition, it is preferable that slurries in which a part of the raw materials match or in which the same raw materials are used but the mixing ratios are different are joined.

When it is desired to change the particle size or shape of the ceramic powder, different ceramic slurries can be prepared for one or both of them.

Further, when it is desired to change the pores, it is possible to prepare in advance slurries having different amounts of introduced bubbles and different bubble diameters. The amount of bubbles introduced into the slurry and the diameter of the bubbles can be adjusted by the type and amount of the surfactant, or the temperature and concentration of the slurry. In addition, it is also possible to prepare slurries having different curing times of the slurry and different slurry holding capacities, and change the amount of bubbles and the diameter of bubbles in the step of curing the slurry. This is because, if the curing time of the slurry is long, the aggregation of bubbles proceeds during the curing step, and large bubbles are likely to be generated. In addition, the smaller the bubble holding ability, the more easily the same length of curing time, the more the bubbles are aggregated, so that large bubbles are easily generated.

The curing time of the slurry can be changed depending on the type and amount of the curing material and the temperature of the slurry. When changing the type and amount of the curing material, the monomer material and the polymerization initiator, each type of catalyst and each amount of addition can be changed, but preferably, the amount of the polymerization initiator and the amount of catalyst added are changed. Is preferred. This is because the control of the curing time is easy. It can also be changed by the type, amount and pH of the gelling agent. When a photocurable resin material is used as the curing material, the curing time can be controlled by adjusting the intensity of light irradiation and the like.

Further, the lower the temperature of the slurry, the lower the polymerization reaction rate usually and the longer the curing time. Therefore, the pores can be changed by changing the temperature of the slurry to be joined.

The ability of the slurry to retain air bubbles can be adjusted by the type and amount of the surfactant used. Preferably, the bubble retention ability is adjusted depending on the type of the surfactant.

(Joining of Ceramic Slurry) Next, the ceramic slurry thus prepared is joined. When two slurries are to be joined, the first and second slurries are brought into contact with the first slurries having a shape retention property enough to substantially maintain the contact interface with the second slurries. . The state of the first slurry is a state before it is completely cured. The first slurry, regardless of whether curing has begun or has begun,
What is necessary is just to have hardness or viscosity which can maintain the contact interface with the slurry of the above. That is, such a state may be provided by curing, or may be provided depending on the state of the slurry before the start of curing. Preferably, such a state of the first slurry is set as a bondable state,
This is the state at the time when the contact interface with the second slurry can be maintained or as close as possible.
If the joining is performed in such a state, the two slurries are brought into contact with each other for as long as possible until the curing is completed, so that a joining state with higher integrity can be obtained.
The progress of the curing is adjusted as necessary in order to obtain a preferable bonding timing and a preferable length of hardening time for obtaining a good bonding state.

The ceramic slurries can be sequentially joined in this way. The joining is, specifically,
It can be carried out by laminating by successively introducing and stacking slurry in a mold. Further, a mold having a movable partition wall that can temporarily partition the region into which the slurry is introduced and another region until the slurry can be joined can be used. Introducing the slurry into one area of such a mold, introducing the slurry to the next area adjacent to this area, and removing the partition separating the two areas when the slurry is ready for joining. For example, the slurry can be brought into contact with and joined to the slurry. According to this mold, various types of bonding interfaces can be formed.

In the production method of the present invention, since the resin is cured in a water-retaining state, the mold is provided with a molding surface made of a material that does not transmit the slurry medium. Further, it is preferable to use a mold in which the evaporation of the slurry medium is suppressed or the slurry medium cannot be evaporated.

(Curing) The obtained joined body is cured in a water-retaining state to obtain a water-retaining cured body. Incidentally, the start of curing, for example, in the case of a slurry in which polymerization is started by the addition of a polymerization initiator, at the time of preparing a slurry obtained by adding a polymerization initiator, or
In the case where curing is performed when a temperature condition is applied, the curing is started at the time when the temperature condition is applied. That is, the time at which the curing starts substantially differs depending on the type of the curing ability of the slurry. Therefore, the curing step of the present invention includes a case where curing is started for the first time in the curing step, and a case where the curing step is started before joining or at the time of preparing the slurry.

When a gelling agent is used as a curing material, the composition is cured by temperature control and / or pH control (adjusted at or before the bubble introduction step). Conditions for curing (temperature, pH, etc.) vary depending on the type of gelling agent, gel concentration, ionic strength in slurry, ceramic content, and the like. The slurry temperature and pH can be set in consideration of these parameters, and the time for curing can be adjusted accordingly. Such curing time control may be performed at the time of preparation of each slurry before joining, although temperature conditions can be given during curing.

In the case of curing using a polymerizable material, the curing is started when polymerization initiation conditions such as a polymerization initiator are given. The time for curing can be adjusted at the time of slurry preparation, depending on the type of monomer, the type of polymerization initiator, the type of solvent, the presence or absence of a polymerization catalyst, and the slurry temperature. At the time of curing, the curing time can be controlled by giving a temperature condition. In addition,
In the case of curing by radical polymerization, since the polymerization is inhibited by oxygen, the operation from the introduction of bubbles to the completion of curing is preferably performed in a nitrogen atmosphere.

In the joined slurry, when the ceramic element is changed (when the particle diameter, shape, bubble holding ability, curing time, etc. are changed), or when the ceramic element is hardened so as to change. In the case where the change in the hardening time is mainly given, such a joined body has a phase having a unique ceramic element in the hardened portion of each slurry, and the change of the ceramic element is controlled. The obtained cured product is obtained.

(Control of pore diameter, pore distribution, etc.) When the bubble-containing slurry is cured, the bubbles existing in the slurry are also stored in the cured product. As a result, the cured body becomes porous. In the curing step of the bubble-containing slurry, bubbles are decomposed and aggregated. Utilizing this, in the curing process,
The bubble diameter can be controlled. Therefore, when the bubble-containing slurry is at least one kind of slurry to be joined, the bubble diameter can be controlled in the bubble-containing slurry portion. Further, as described above, the longer the curing time of the slurry, the larger the bubble diameter. Therefore, when the curing times of the bubble-containing slurries to be joined are different, the bubble diameters are different in the cured portions of the respective slurries. Also, since the bubble diameter becomes smaller as the bubble holding capacity of the slurry is larger, when the bubble holding capacity is different in the slurries to be joined, the cured portion of each slurry has a different bubble diameter. Due to the difference in curing time and the size of the bubble holding ability, the size of the change in the bubble diameter can be easily imparted to the slurry to be joined. Further, the distribution of the bubble diameter can be easily controlled by the thickness and shape of the slurry to be joined.

When the curing of the present invention is utilized, unlike the conventional slip casting method, there is no orientation of the ceramic powder as a raw material, and the ceramic powder is uniformly dispersed and held to obtain a uniform matrix. Therefore, a uniform matrix can be obtained without the orientation of the raw material powder. Further, in the method of the present invention, the formation of bubbles can be controlled in a state where the raw material particles are uniformly held without being oriented by controlling the bubble holding ability and / or the curing time of the slurry. Further, since the control of the bubble holding ability and the curing time can be easily controlled, the degree of freedom of the bubble control is high. Further, since the solidification is performed while holding the medium component, a molded body having a smooth surface and reduced cracks and roughness can be obtained. In addition, because the matrix is supported by a gelling agent or a polymer, the cured product has higher strength than conventional cast moldings, and is convenient for handling in the process up to firing, Are unlikely to occur.

The use of the cured product is advantageous in obtaining a large-sized ceramic material having a complicated shape because of lack of orientation, good moldability, and high strength. Is good. Furthermore, since the present cured body passes through the joined body, a complicated shape can be easily selected, and the change of the ceramic element is highly controlled. In particular, a complicated three-dimensional shape is easily provided by laminating and joining the slurries.

(Drying, Degreasing, Firing) After obtaining a cured product in a desired form in this way, if necessary, it is demolded, dried, degreased, and fired. In the method of the present invention, since a water-impermeable molding die is used as the molding die, it is easy to release and, since it is a water-retentive cured product, the cured product is not easily damaged during release. Drying is performed so as to evaporate water and a solvent contained in the cured product. Drying conditions (temperature,
Humidity, time, etc.) are appropriately adjusted depending on the type of solvent used for preparing the slurry and the component (gelling agent or polymer) constituting the skeleton portion of the cured product. In particular, in the present method, in the drying step, it is preferable to prevent the movement of pores and the occurrence of decomposition and aggregation by drying. That is, it is preferable that the drying step is performed while holding the pores in the molded body. By drying in this manner, the orientation of the ceramic powder present in the matrix at the time of curing is preserved.

In the case of curing from an aqueous slurry, the usual drying temperature is 20 ° C. or more, preferably 25 ° C. to 80 ° C., more preferably 25 ° C. to 40 ° C.
It is as follows. Also, it is usually one hour or more. Preferably, it is at least 8 hours, more preferably at least 24 hours.
In addition, it is more preferable to dry at a temperature of 20 ° C. or more and 30 ° C. or less, preferably about 25 ° C. for about 24 hours to about 200 hours, while controlling the humidity (relative humidity) so as to gradually decrease. 95% RH relative humidity
To 60% RH. Also, 5
It is preferable to reduce by 10% RH / day. Such drying is particularly suitable for drying a molded body using water as a medium. For example, in the case of a gel-like porous molded body prepared from a slurry using water as a medium and methacrylamide and N, N'-methylenebisacrylamide as monomers, the humidity is increased from 95% to 60% RH at 25 ° C.
Dried at 〜１０10% / day and dried for about one week.
In the case of a molded article from an organic solvent-based slurry, usually 40
C. or higher, preferably 110 ° C. or higher.

Next, in order to remove organic components from the dried cured product, heating is performed at a higher temperature. The temperature and time for degreasing are adjusted according to the amount and type of organic components used. For example, a cured product prepared from a slurry using methacrylamide and N, N-methylenebisacrylamide as materials for gelling was degreased at 700 ° C. for 2 days.

After the degreasing, a firing step is performed. Conditions for firing are set in consideration of the type of ceramic powder used and the like. In particular, when a ceramic powder having an average particle diameter of submicron (0.1 μm to 0.6 μm) is used, the matrix can be densified by sintering at a high temperature.

Through the above steps, a ceramic material is obtained. ADVANTAGE OF THE INVENTION According to this invention, a desired three-dimensional shape, especially a complicated three-dimensional shape can be given to a ceramic material by joining slurry, and the change of a ceramic element can also be given at the same time. Further, the ceramic material of the present invention can be obtained by the above steps. The ceramic material of the present invention is obtained from the bonded slurry.
A joined body of the above ceramic matrix phase is obtained. Further, two or more matrices may be completely the same, or some or all of the ceramic elements may be different. When matrices are derived from ceramic slurries of different matrix elements, matrix boundaries are provided between these matrices.

In the case where the obtained matrix has a different pore diameter or pore volume, a particularly distinct boundary surface is provided.
In particular, when only the pores change at the bonding interface as the ceramic element, the matrix is completely the same even if the boundary surface is detected, so that the ceramic material has extremely high integrity.

Since the ceramic material obtained by the method of the present invention is not oriented, shrinkage during firing also occurs isotropically. As a result, the dimensional accuracy is improved, and there is no crack or the like. In addition, the cured product has no orientation of the raw materials and is uniform, and the release of the molded product is easy,
Also, since the strength of the molded body is sufficient, the molded body is hardly damaged or distorted, and the sintered body is hardly defective. As a result, the manufacturing method is such that a ceramic material having high strength can be obtained. Further, according to the present method, a sintered body having a smooth surface can be obtained. In addition, since a sintered body faithful to the shape of the molded body can be obtained, it is easy to obtain a large-sized or complicated shaped sintered body.

The method for producing a ceramic material of the present invention comprises:
In particular, since the distribution of pore diameter and volume can be easily and controlled,
It is possible to obtain a material with a highly controlled pore distribution or a gradient material for pores. Therefore, the method of the present invention is suitable as a method for manufacturing a dust collecting filter, a gas filter, and a filter for water treatment, and particularly suitable as a method for manufacturing these filters used at high temperatures. Further, the ceramic material of the present invention is suitable as these filter materials.

[0050]

According to the present invention, it is possible to provide a ceramic material capable of easily controlling ceramic elements.

[0051]

The present invention will be specifically described below with reference to examples. (Preparation of ceramic slurry) Showa Denko easily sinterable alumina (AL-160SG)
-4 *, average particle size: 0.47 μm). Nonionic K20 is used as a surfactant for introducing bubbles.
4 (polyoxyethylene lauryl ether) and lapizole A80 (sodium dioctyl sulfosuccinate). It has been found that the two surfactants differ in the stability of the introduced bubbles in the slurry having the composition of this example. As a dispersant, a polycarboxylic acid ammonium salt (Celna D-305, manufactured by Chukyo Yushi) was used, methacrylamide was used as a monomer, and N, N ′ was used as a crosslinking agent.
Methylene bisacrylamide, as catalyst N, N,
N ′, N′-tetramethylethylenediamine (all manufactured by Wako Pure Chemical Industries, Ltd.) was used.

A total of 830 g of zirconia balls (diameter 25 mm and diameter 5 mm) were placed in a 1 L pot. In this pot, 24.4 g of methacrylamide and 6.10 g of N, N'-methylenebisacrylamide were dissolved in 134.5 g of distilled water, and 5.06 g of ammonium polycarboxylate dispersant was added. Was used as a dispersion solvent. Then, 830 g of alumina was added to the dispersion solvent.
The mixture was charged in batches and mixed in a constant temperature water bath (25 ° C.) for 48 hours by a wet ball mill (60 rpm) to prepare a ceramic slurry. The composition ratio of this slurry was a solid concentration (alumina: 83 wt%, dispersant: 0.5 wt%, methacrylamide: 2.24 wt%, N, N'-methylenebisacrylamide: 0.61 wt%). The slurry was further filtered through a 200-mesh filter, and then subjected to vacuum degassing (8 minutes) in combination with an ultrasonic generator, in order to suppress evaporation of water. , Ice water was used.

(Introduction of Bubbles and Bonding of Ceramic Slurry) Hereinafter, the operation was performed in a nitrogen atmosphere until the hardening of the ceramic slurry was completed. (Test Example 1) 300 g of the defoamed slurry was weighed into 500 ml beakers. 0.5 ml of Nonion K204 was added to one slurry, and 0.5 ml of Lapisol A80 was added to the other slurry, and air bubbles were introduced by mechanical stirring (hand mixer, 5 minutes). Slurries 1 and 2 were prepared. Subsequently, 0.05 g of ammonium persulfate dissolved in 0.4 g of distilled water and 0.2 ml of a catalyst (N, N, N ', N'-tetramethylethylenediamine) were added to each slurry as a polymerization initiator, Stirring was further performed for mixing. The temperature of each of the slurries 1 and 2 was 22 ° C. Next, as shown in FIG. 2, a cell-containing ceramic slurry 1 is formed into a molding die (disc type: 70 m in diameter).
m, made of Teflon (registered trademark)), and after 1 to 2 minutes, the bubble-containing ceramic slurry 2 was poured thereon, and the slurry was joined in a laminated state. After joining,
It was left in a glove box (room temperature) for 1.5 hours to cure.

In the curing process, the aggregation of bubbles is suppressed in the slurry 1 having high bubble stability, and the aggregation of bubbles is promoted in the slurry 2 having low bubble stability as compared with the slurry 1. The bubbles of the hardened phase derived from the slurry 2 became larger than the bubbles of the hardened phase derived from the slurry 1.
In the process from joining to curing, the interface at the time of lamination was stably maintained.

The water-retained cured product obtained from the joined body of the slurries 1 and 2 was released from the mold. The cured product had good integrity. This cured product was heated at 25 ° C. H. 95% to 60
% While drying at a humidity of 10% / day. further,
The cured product was heated at 700 ° C. for 8 hours to degrease it, and then baked at 1550 ° C. for 2 hours to obtain a ceramic material 10. Note that the inside of each furnace was in an oxidizing atmosphere.

As shown in FIG. 3, the obtained ceramic material 10 was a porous ceramic material having a distinctly different ceramic phase in terms of pore diameter and porosity. The joining interface was clearly visible between these ceramic phases having different pore diameters and porosity, while the two matrix phases were well integrated at the joining interface.
The bonding interface was substantially along the horizontal direction during curing. The porosity of the ceramic phase derived from the slurry 1 is 5
5%, ceramic phase derived from slurry 2 has porosity of 7
0%, and the average porosity of the ceramic material 10 is 66%.
%Met.

(Test Example 2) 300 g of defoamed slurry
Each was weighed into a 500 ml beaker.
To each of the slurries was added Nonion K 2040.5 ml, and each was mechanically stirred (hand mixer, 5
), Bubbles were introduced to prepare bubble-containing ceramic slurries 3 and 4. Subsequently, 0.25 g of ammonium persulfate dissolved in 0.4 g of distilled water as a polymerization initiator and a catalyst (N, N, N ', N'-) were added to the slurry 3.
0.2 ml of tetramethylethylenediamine)
On the other hand, slurry 4 contained 0.02 g of ammonium persulfate dissolved in 0.4 g of distilled water and catalyst (N, N, N ′,
(N′-tetramethylethylenediamine) 0.1 ml was added and further stirred for mixing. The temperature of each of the slurries 3 and 4 was 22 ° C. Next, as shown in FIG. 4, the cell-containing ceramic slurry 3 is poured into a molding die (disc type: 70 mm in diameter, made of Teflon), and after 1-2 minutes, the cell-containing ceramic slurry 4 is poured thereon and laminated. The slurry was joined in this state. After joining, 1. in a glove box (room temperature).
It was left to cure for 5 hours. Next, the cured bodies of the joined bodies of the slurries 3 and 4 were released. The cured product had good integrity. The cured product was dried, degreased, and fired in the same manner as in Test Example 1 to obtain a ceramic material 20.

In the curing process, the slurry 3 containing a larger amount of the polymerization initiator cures faster than the slurry 4, and as a result, the cured product has a smaller size in the cured phase derived from the slurry 3. Air bubbles were retained. In the process from joining to curing, the interface at the time of lamination was stably maintained. As shown in FIG. 5, the ceramic material 20 obtained from such a cured body was a porous ceramic material having a ceramic phase that was clearly different in terms of pore diameter and porosity. The joining interface was clearly visible between these ceramic phases having different pore diameters and porosity, while the two matrix phases were well integrated at the joining interface. The bonding interface was substantially along the horizontal direction during curing. The porosity of the ceramic phase derived from the slurry 3 was 54%, the porosity of the ceramic phase derived from the slurry 4 was 65%, and the average porosity of the ceramic material 20 was 62%.

(Test Example 3) 300 g of defoamed slurry
Each was weighed into a 500 ml beaker, and the slurry temperature was adjusted to 35 ° C. and 6.5 ° C. using a water bath. While maintaining the respective slurry temperatures, 0.54 ml of Nonion K204 was added to each of the slurries, and bubbles were introduced by mechanical stirring (hand mixer, 5 minutes), and the bubbles-containing ceramic slurry 5 (slurry temperature 35 ° C.) ) And 6 (slurry temperature 6.5 ° C) were prepared. Subsequently, while maintaining the slurry temperature, 0.05 g of ammonium persulfate dissolved in 0.4 g of distilled water as a polymerization initiator and a catalyst (N, N,
N ', N'-tetramethylethylenediamine) 0.2 m
were added and each was further stirred for mixing. Next, as shown in FIG. 6, the cell-containing ceramic slurry 5 is poured into a molding die (disc type: 70 mm in diameter, made of Teflon), and after 1-2 minutes, the cell-containing ceramic slurry 6 is poured thereon and laminated. The slurry was joined in this state. After joining, 1. in a glove box (room temperature).
It was left to cure for 5 hours. Next, the cured bodies of the joined bodies of the slurries 5 and 6 were released from the mold. The cured product had good integrity. The cured product was dried, degreased, and fired in the same manner as in Test Example 1 to obtain a ceramic material 30.

In the curing process, the slurry 5 having a higher slurry temperature cures faster than the slurry 6 having a lower temperature. As a result, the slurry 5
, Smaller bubbles were retained in the cured phase. In the process from joining to curing, the interface at the time of lamination was stably maintained.

As shown in FIG. 7, the ceramic material 30 obtained from such a cured body was a porous ceramic material having a ceramic phase that was clearly different in terms of pore diameter and porosity. The joining interface was clearly visible between these ceramic phases having different pore diameters and porosity, while the two matrix phases were well integrated at the joining interface. The bonding interface was substantially along the horizontal direction during curing. The porosity of the ceramic phase derived from the slurry 5 was 58%, the porosity of the ceramic phase derived from the slurry 6 was 82%, and the average porosity of the ceramic material 30 was 65%.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a manufacturing process of a ceramic material of the present invention.

FIG. 2 is a diagram showing joining to curing in Example 1.

FIG. 3 is a view showing a phase structure of the ceramic material obtained in Example 1.

FIG. 4 is a diagram showing bonding to curing in Example 2.

FIG. 5 is a view showing a phase structure of the ceramic material obtained in Example 2.

FIG. 6 is a diagram showing bonding to curing in Example 3.

FIG. 7 is a view showing a phase structure of the ceramic material obtained in Example 3.

[Explanation of symbols]

 1,2,3,4,5,6 ceramic slurry 10,20,30 ceramic material

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makio Naito 2-4-1 Rokuno, Atsuta-ku, Nagoya City, Aichi Prefecture Inside the Fine Ceramics Center (72) Inventor Hiroya Abe Rokuno, Atsuta-ku, Nagoya City, Aichi Prefecture (4-1) Fukui Takehisa Fukui 2-4-1 Rokuno, Atsuta-ku, Nagoya-shi, Aichi Japan Fine Ceramics Center (72) Inventor Kaoru Aino Nagoya, Aichi 2-4-1 Rokuno, Atsuta-ku Fine Ceramics Center F term (reference) 4G030 AA36 GA16 GA18 GA20 4G052 AB24 AB30 AB42 AB51 4G055 AA08 AC01 CA01

Claims (6)

[Claims] 1. A method for producing a ceramic material, comprising: a step of joining a ceramic slurry having curability; and a step of curing a joined body of the ceramic slurry obtained in the step in a water-retaining state to form a water-retaining cured body. Obtaining a cured product, drying the cured product, degreasing the dried cured product, and firing the degreased cured product. 2. A method for producing a ceramic material, comprising: a step of joining one or more types of ceramic slurries having a hardening ability and capable of imparting a change of a predetermined ceramic element to the ceramic material; A method of curing in a water-retaining state to obtain a water-retained cured body, a step of drying the cured body, a step of degreased the dried cured body, and a step of firing the degreased cured body. . 3. The method according to claim 1, wherein a ceramic slurry containing bubbles is used as the ceramic slurry. 4. The method according to claim 3, wherein two or more types of ceramic slurries having different cell holding ability and / or curing time of the cell-containing ceramic slurry are used. 5. Water retention of a ceramic raw material in which at least one type of ceramic element selected from the group consisting of raw material composition, raw material particle size, raw material particle form, pore diameter, and porosity changes continuously or intermittently. A method for producing a ceramic material, in which a hardened material is fired. 6. Two or more ceramic raw material phases different in at least one type of ceramic element selected from the group consisting of a raw material composition, a raw material particle diameter, a raw material particle form, a pore diameter, and a porosity are joined and fired. Is a ceramic material.