JP2013082170A - Method for manufacturing ceramics joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramics joined body that can control causing crack or peeling to the joint after the sintering.SOLUTION: The method for manufacturing ceramics joined body 3 includes: processes (S10, S20) that individually form first and second ceramic formed bodies 1 and 2 that comprise mutually the similar materials; a process (S30) that forms the ceramics joined body 3 by fitting the first and second ceramic formed bodies 1 and 2 by using the isostatic pressing; and a process (S40) that sinters the ceramics joined body 3. Each forming pressure when the first and second ceramic formed bodies 1 and 2 are individually formed is lower than the forming pressure of the isostatic pressing. The forming pressure of the first ceramic formed body 1 when the first and second ceramic formed bodies 1 and 2 are individually formed is lower than the forming pressure of the second ceramic formed body 2. The second ceramic formed body 2 is fitted in the first ceramic formed body 1 and the ceramics joined body 3 is obtained in the isostatic pressing.

Description

  The present invention relates to a method for producing a ceramic joined body, and more particularly to a method for producing a ceramic joined body for forming a ceramic joined body by joining ceramic formed bodies.

  In recent years, the development of ceramics on components of apparatus and devices that are required to be lightweight, heat resistant, and corrosion resistant has been advanced. Applications where ceramics are put into practical use include bearings and engine parts. However, most of the members made of ceramics used for bearings, engine parts, and the like are balls, rollers, ring materials, and the like that have a relatively simple shape. In the future, if complex shapes or large ceramic members can be manufactured, the use is expected to expand further.

  As a method of forming the ceramic powder into a desired shape, various forming methods are adopted depending on the desired shape and the intended use of the product. Examples of the molding method include a mold press method, an injection molding method, an extrusion molding method, and a casting molding method. However, there is a limit to the shape or size that can be manufactured due to manufacturing restrictions. As another forming method, there is a method in which parts manufactured as a sintered product using ceramic powder are joined by brazing or an adhesive. However, in this method, there is a possibility that the strength of the joint portion is reduced due to insufficient strength of the joining agent itself or a difference in thermal expansion coefficient between the base material and the joining agent.

  Further, a method having the following steps has been proposed as a method for manufacturing a ceramic member having a complicated shape. First, a part having a simple shape is produced by dividing the whole into a plurality of parts. A ceramic member is formed in a predetermined shape by combining and joining parts having simple shapes. Then, the ceramic member is sintered. In this way, a ceramic member having a complicated shape is manufactured.

  As the above method, for example, in JP-A-2-236205 (Patent Document 1), a plurality of molded bodies are joined via a slurry composed of a powder material that generates a liquid phase during sintering, a polymer binder, and a solvent. In this state, a method of joining a plurality of molded bodies by sintering a powder material has been proposed. Since this method is only bonding and no pressure treatment is applied, the strength of the bonded portion after sintering is reduced.

  Further, for example, in JP-A-5-254947 (Patent Document 2) and JP-A-2002-254420 (Patent Document 3), the molded bodies are mutually connected via a slurry having the same composition or main components as the molded bodies. Has been proposed which is sintered in a state in which is bonded by pressing or CIP (cold isostatic pressing) molding. In the method described in Japanese Patent Application Laid-Open No. 5-254947, cold isostatic pressing for bonding molded bodies to each other is performed under a molding pressure of each molded body. Moreover, in the method described in Unexamined-Japanese-Patent No. 2002-254420, the molded object is joined by pressurization, without using cold isostatic pressing. In the methods described in JP-A-5-254947 and JP-A-2002-254420, since the molded bodies are bonded to each other through a slurry having the same composition or the same main component, the strength of the bonded portion is increased. It is expected to have a strength close to that of the molded body as the base material.

JP-A-2-236205 JP-A-5-254947 JP 2002-254420 A

  However, there are the following problems even when the molded bodies are joined to each other via a slurry having the same composition or the same main component, so that the strength of the joint is close to that of the molded body as the base material. In other words, when the compacts are joined to each other at a molding pressure equal to or lower than the compacting pressure, even if the compacts are formed of the same material, due to the difference in sintering shrinkage depending on the molding method or molding conditions of each joined member, There is a problem that cracks or peeling occurs in the joint after sintering.

  This invention is made | formed in view of the said subject, The objective is to provide the manufacturing method of the ceramic joined body which can suppress that a crack or peeling arises in the junction part after sintering.

  The method for manufacturing a ceramic joined body according to the present invention includes a step of individually molding the first and second ceramic molded bodies made of the same kind of material, and isotropic pressure molding of the first and second ceramic molded bodies. The method includes a step of forming a ceramic joined body by fitting and a step of sintering the ceramic joined body. The respective molding pressures when the first and second ceramic molded bodies are individually molded are lower than the molding pressure of isotropic pressure molding. The molding pressure of the first ceramic molded body when molding the first and second ceramic molded bodies individually is lower than the molding pressure of the second ceramic molded body. During the isotropic pressure forming, the second ceramic molded body is fitted to the first ceramic molded body to obtain a ceramic joined body. Here, the same kind of material means a material having the same main component.

  The inventors set the molding pressure when molding a plurality of ceramic compacts to be joined to a molding pressure lower than the molding pressure at the time of isotropic pressure molding for the purpose of joining, and molding the plurality of ceramic compacts differently. Isotropic pressure molding by bonding by isotropic pressure molding to a molded body in which a ceramic molded body molded at high molding pressure is fitted to a ceramic molded body molded at low pressure and molded at low molding pressure It has been found that when the bonded body is sintered, it is possible to suppress the occurrence of cracks or peeling at the fitting portion (bonding portion) or the like. As a result, a complex or large-sized sintered body having substantially uniform characteristics can be obtained.

  That is, the molding pressure when molding a plurality of ceramic compacts to be joined is set to a molding pressure lower than the molding pressure at the time of isotropic pressure molding for the purpose of joining, so that the isotropic pressure for the purpose of joining. A plurality of ceramic molded bodies that are processed under pressure molding by molding are molded bodies that are substantially equivalent to molded bodies obtained by isotropic pressure molding for bonding purposes. As a result, the entire bonded body has a substantially uniform pressure distribution. Since the entire joined body has a uniform pressure distribution, the shrinkage characteristics during sintering are also uniform. At the same time, the ceramic compact of low molding pressure shrinks more than the ceramic compact of high molding pressure by isostatic pressing for the purpose of joining. Crimped to the ceramic body. Therefore, it can suppress that a crack or peeling arises in a fitting part etc. when sintering. As a result, a complex or large-sized sintered body having substantially the same physical properties including the fitting portion can be obtained.

  According to the method for manufacturing a ceramic joined body of the present invention, the ceramic joined body is formed by fitting the first and second ceramic formed bodies using isotropic pressure forming, and the first and second ceramic formed bodies are formed. The molding pressure when molding the body individually is lower than the molding pressure of isotropic pressure molding. The molding pressure of the first ceramic molded body when the first and second ceramic molded bodies are individually molded is lower than the molding pressure of the second ceramic molded body, and the first ceramic molded body is subjected to isostatic pressure molding. The ceramic molded body is obtained by fitting the second ceramic molded body to one ceramic molded body. For this reason, the 1st and 2nd ceramic compact is joined by the forming pressure in the case of isotropic pressure forming by isotropic pressure forming. As a result, the entire ceramic joined body is molded at a molding pressure reached by isostatic pressing. Therefore, since the entire ceramic joined body has a uniform pressure distribution, the shrinkage characteristics during sintering are also uniform. At the same time, the first ceramic molded body having a low molding pressure is pressure-bonded to the second ceramic molded body having a high molding pressure at the fitting portion. Therefore, it can suppress that a crack or peeling arises in a fitting part etc. when sintering.

  Preferably, in the above method for manufacturing a ceramic joined body, each of the molding pressures when the first and second ceramic molded bodies are individually molded is 5 MPa or more, and 2/3 of the molding pressure of isotropic pressure molding. It is as follows. The respective molding pressures when the first and second ceramic molded bodies are individually molded may be lower in principle than the molding pressure at the isotropic pressure molding for the purpose of joining. However, if the molding pressure when molding the first and second ceramic molded bodies individually exceeds 2/3 of the molding pressure at the isotropic pressure molding, isotropic pressure molding for the purpose of joining is performed. The effect of correcting to a molded body equivalent to the obtained molded body is hardly obtained. As a result, the shrinkage characteristics of the ceramic joined body during sintering in the joint portion are not uniform, resulting in a decrease in strength in the joint portion. Therefore, the isotropic pressure for the purpose of joining is obtained by setting the molding pressure when molding the first and second ceramic molded bodies individually to 2/3 or less of the molding pressure at the isotropic pressure molding. The effect of correcting to a molded body equivalent to the molded body obtained by molding can be reliably obtained.

  In addition, if the molding pressure when molding the first and second ceramic compacts individually is less than 5 MPa, it is difficult or impossible to retain the shape of each compact. There is a possibility of breakage during isostatic pressing for the purpose of joining. Therefore, each of the first and second ceramic molded bodies can be easily retained by setting the respective molding pressures when individually molding the first and second ceramic molded bodies to 5 MPa or more. . Moreover, it can suppress that the 1st and 2nd ceramic molded object is damaged at the time of isotropic pressure forming.

  Preferably, in the above method for manufacturing a ceramic joined body, a difference in molding pressure between the first and second ceramic compacts when the first and second ceramic compacts are individually molded is 10% or more. . If the difference in molding pressure between the first and second ceramic molded bodies when molding the first and second ceramic molded bodies individually is less than 10%, isotropic pressure molding for the purpose of joining Sometimes, the shrinkage difference due to the molding pressure difference between the first and second ceramic molded bodies is small, so that the crimping action of the fitting portion does not occur sufficiently. In particular, when a gap is provided in the fitting portion so that the fitting can be easily performed and the first and second ceramic molded bodies are combined, the gap remains even after isotropic pressure forming for the purpose of joining. The strength is significantly reduced. Therefore, the first and second ceramics are formed by setting the difference in molding pressure between the first and second ceramic compacts to 10% or more when individually molding the first and second ceramic compacts. By increasing the shrinkage difference caused by the molding pressure difference of the molded body, the crimping action of the fitting portion can be sufficiently generated.

  In the method for manufacturing a ceramic joined body, preferably, the first and second ceramic formed bodies include either oxide ceramics or non-oxide ceramics. Thereby, either oxide ceramics or non-oxide ceramics can be applied to the material of the first and second ceramic molded bodies.

  In the above-described method for manufacturing a ceramic joined body, the main components of the first and second ceramic molded bodies are preferably the same. Here, the main component means a component having the largest content ratio. Thereby, even if additive materials, such as a sintering auxiliary agent and a dispersion reinforcement, differ a little, the ceramic joined body which can suppress that a crack or peeling arises by a fitting part etc. can be obtained when sintered.

  Preferably, in the above-described method for manufacturing a ceramic joined body, the steps of individually forming the first and second ceramic compacts include a die press, a uniaxial rubber press, a cold isostatic press, extrusion molding, injection molding, and A step of forming at least one of the first and second ceramic molded bodies by one or more selected from the group consisting of slip casting. Thereby, a wide shaping | molding method is employable when shape | molding the 1st and 2nd ceramic molded object separately. Further, the first and second ceramic molded bodies can be molded by different molding techniques.

  In the above method for producing a ceramic joined body, preferably, the first and second ceramic molded bodies are bonded together with a bonding material in the isostatic pressing. Since the first and second ceramic molded bodies are bonded to each other with a bonding material, the first and second ceramic molded bodies can be accurately combined.

  In the method for manufacturing a ceramic joined body, preferably, the joining material is made of a slurry having the same main component as the main components of the first and second ceramic molded bodies. Thereby, the intensity | strength of a junction part can be made into the intensity | strength equivalent to the 1st and 2nd ceramic molded object.

  In the above method for manufacturing a ceramic joined body, preferably, the isotropic pressure forming is wet cooling in which the first and second ceramic compacts are joined by pressurizing the first and second ceramic compacts with a pressurized liquid. It is isostatic pressing. Since the first and second ceramic molded bodies are pressurized with a pressurized liquid, a mold or jig matching the shape of the joined body is not necessary. Therefore, productivity can be improved.

  In the above method for manufacturing a ceramic joined body, the first and second shielding films are preferably disposed between the pressurized liquid and the first and second ceramic compacts during wet cold isostatic pressing. With the ceramic molded body covered, the first and second ceramic molded bodies are joined by pressing the first and second ceramic molded bodies with a pressurized liquid through the shielding film. For this reason, the first and second ceramic molded bodies can be protected from the pressurized liquid by the shielding film.

  Preferably, in the above method for manufacturing a ceramic joined body, the shielding film is formed in a bag shape having one end where the opening is opened, the first and second ceramic molded bodies are accommodated in the shielding film, and one end is sealed. In this state, the internal space of the shielding film is decompressed. Thereby, the shaping | molding defect by the gas enclosed by internal space and the failure | damage of a shielding film can be suppressed.

  Preferably, in the above method for producing a ceramic joined body, the shielding film is formed of a film formed by either dip coating or spraying of a material that becomes rubberized by either drying or heating. Since the coating adheres along the outer shape of the first and second ceramic molded bodies, the shielding film can be applied to a more complicated shape.

  Preferably, in the method for manufacturing a ceramic joined body, the first and second ceramic molded bodies have the first and second coatings in a state in which the joint is covered with a protective member so that the coating does not enter the joint portions of the first and second ceramic molded bodies. It is formed on the second ceramic molded body. Thereby, the penetration of the coating film into the joint can be prevented.

  As described above, according to the method for manufacturing a ceramic joined body of the present invention, it is possible to suppress the occurrence of cracks or peeling at the joined portion after sintering.

It is a figure which shows the outline of the manufacturing method of the ceramic joined body in one embodiment of this invention. It is sectional drawing which shows the outline of the process of shape | molding the 1st ceramic molded object in one embodiment of this invention. It is sectional drawing which shows the outline of the process of shape | molding the 2nd ceramic molded object in one embodiment of this invention. It is sectional drawing which shows the outline of the process of shape | molding a ceramic joined body by joining the 1st and 2nd ceramic molded body in one embodiment of this invention. It is sectional drawing which shows the outline of the process of sintering the ceramic joined body in one embodiment of this invention. It is a schematic sectional drawing which shows a mode that the 1st and 2nd ceramic molded object in one embodiment of this invention is covered with a shielding film. It is a schematic sectional drawing which shows the state by which the 1st and 2nd ceramic molded object in one embodiment of this invention was covered with the shielding film. It is a schematic sectional drawing which shows a mode that the material of a shielding film is dip-coated on the 1st and 2nd ceramic molded object in one embodiment of this invention. It is a schematic sectional drawing which shows the state by which the 1st and 2nd ceramic molded object in one embodiment of this invention was covered with the shielding film which consists of a film. It is a schematic sectional drawing which shows a mode that the material of a shielding film is injected to the 1st and 2nd ceramic molded object in one embodiment of this invention. It is a schematic plan view which shows the state by which the junction part of the 1st and 2nd ceramic molded object in one embodiment of this invention was covered with the protection member. It is a schematic sectional drawing which shows a mode that the film was formed in the state in which the junction part of the 1st and 2nd ceramic molded object in one embodiment of this invention was covered with the protection member. It is a schematic perspective view which shows the state before the 1st and 2nd ceramic molded object of the Example of this invention is joined. It is a schematic perspective view which shows the ceramic joined body to which the 1st and 2nd ceramic molded body of the Example of this invention was joined. It is a schematic perspective view which shows the state before the 1st and 2nd ceramic molded body of another shape of the Example of this invention is joined. It is a schematic perspective view which shows the ceramic joined body to which the 1st and 2nd ceramic molded object of the other shape of the Example of this invention was joined. It is a schematic sectional drawing which shows the fitting part of the ceramic joined body of the other shape of the Example of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Initially, the manufacturing method of the ceramic joined body of one embodiment of the present invention is explained.

  With reference to FIG. 1, the outline | summary of the manufacturing method of the ceramic joined body of one embodiment of this invention is demonstrated. In the method of manufacturing a ceramic joined body according to one embodiment of the present invention, first, a step of individually forming a first ceramic molded body and a second ceramic molded body made of the same kind of material is performed. That is, the first ceramic molded body molding step (S10) and the second ceramic molded body molding step (S20) are performed separately.

  Next, the process (S30) which shape | molds a ceramic joined body by fitting a 1st and 2nd ceramic molded object using isotropic pressure forming is implemented. Next, a step (S40) of sintering the ceramic joined body is performed. And each shaping | molding pressure at the time of shape | molding a 1st and 2nd ceramic molded object separately is lower than the shaping pressure of isotropic pressure forming. The molding pressure of the first ceramic molded body when molding the first and second ceramic molded bodies individually is lower than the molding pressure of the second ceramic molded body. During the isotropic pressure forming, the second ceramic molded body is fitted to the first ceramic molded body to obtain a ceramic joined body.

  Next, a method for manufacturing a ceramic joined body according to an embodiment of the present invention will be described in more detail.

First, referring to FIG. 2 and FIG. 3, in the first ceramic molded body molding step (S10) and the second ceramic molded body molding step (S20), the first ceramic molded body is formed by, for example, a die press The first and second ceramic molded bodies 2 are molded. That is, when the ceramic powder is pressed by the upper mold 11, the lower mold 12, and the side mold 13, the first ceramic molded body 1 and the second ceramic molded body 2 are molded. The first ceramic molded body 1 is formed in a cylindrical shape, for example. The second ceramic molded body 2 is formed in a cylindrical shape, for example. The first ceramic molded body 1 is formed so that the second ceramic molded body 2 can be fitted on the inner peripheral side. The respective molding pressures when the first ceramic molded body 1 and the second ceramic molded body 2 are individually molded are lower than the molding pressure of isotropic pressure molding. The molding pressure of the first ceramic molded body 1 when the first ceramic molded body 1 and the second ceramic molded body 2 are individually molded is lower than the molding pressure 2 of the second ceramic molded body. Each molding pressure at the time of individually molding the first ceramic molded body 1 and the second ceramic molded body 2 before the isotropic pressure molding is preferably 5 MPa or more. In addition, the difference in molding pressure between the first ceramic molded body 1 and the second ceramic molded body 2 when the first ceramic molded body 1 and the second ceramic molded body 2 are individually molded is 10% or more. It is preferable that ,
The first ceramic molded body 1 and the second ceramic molded body 2 contain either oxide ceramics or non-oxide ceramics. That is, oxide ceramics such as alumina and zirconia and non-oxide ceramics such as silicon nitride, silicon carbide, and aluminum nitride can be applied to the materials of the first ceramic molded body 1 and the second ceramic molded body 2.

  Moreover, it is preferable that the main component of the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 is the same. The first ceramic molded body 1 and the second ceramic molded body 2 may have an auxiliary for sintering (sintering auxiliary) in addition to the main component. Further, the first ceramic molded body 1 and the second ceramic molded body 2 may have a dispersion strengthening material. Further, the first ceramic molded body 1 and the second ceramic molded body 2 have inevitable impurities.

  Each of the first ceramic molded body 1 and the second ceramic molded body 2 can be molded by a die press, a uniaxial rubber press, a cold isostatic press, extrusion molding, injection molding, slip casting, or the like. The first ceramic molded body 1 and the second ceramic molded body 2 may be molded by different molding methods.

  Next, referring to FIG. 4, in the step of forming the ceramic joined body (S30), the first ceramic molded body 1 and the second ceramic molded body 2 are joined by isotropic pressure molding. Cold isostatic pressing such as wet cold isostatic pressing, dry cold isostatic pressing and rubber mold cold isostatic pressing can be applied as isostatic pressing, but wet cold isostatic pressing is applicable. Is preferred. The first ceramic molded body 1 and the second ceramic molded body 2 disposed in a space surrounded by the upper member 21, the lower member 22, and the side member 23 are pressurized by a pressurized liquid 24 that is a pressure medium. Is done. By being uniformly pressurized by the pressurized liquid 24, the first ceramic molded body 1 and the second ceramic molded body 2 are bonded to form the ceramic bonded body 3. During the isostatic pressing, the second ceramic molded body 2 is fitted to the first ceramic molded body 1 to obtain the ceramic bonded body 3.

  That is, the second ceramic molded body 2 is fitted to the first ceramic molded body 1 by sandwiching the periphery of the second ceramic molded body 2 with the first ceramic molded body 1. The first ceramic molded body 1 and the second ceramic molded body 2 are fitted so that the cylindrical second ceramic molded body 2 penetrates the cylindrical first ceramic molded body 1. The entire circumference around the second ceramic molded body 2 is covered with the inner peripheral side of the cylindrical first ceramic molded body 1.

  It is preferable that the molding pressure when molding the first ceramic molded body 1 and the second ceramic molded body 2 individually is 2/3 or less of the molding pressure of isotropic pressure molding.

  Further, it is preferable that the first ceramic molded body 1 and the second ceramic molded body 2 are bonded in a state where they are bonded to each other by the bonding material 4 during the isotropic pressure forming. The bonding material 4 is preferably made of a slurry having the same main component as the main components of the first ceramic molded body 1 and the second ceramic molded body 2. The bonding material 4 may be a polymer adhesive that is thermally decomposed during sintering.

  Moreover, it is preferable that the shielding film 5 is disposed between the pressurized liquid 24 and the first ceramic molded body 1 and the second ceramic molded body 2 during wet cold isostatic pressing. The shielding film 5 is for protecting the first ceramic molded body 1 and the second ceramic molded body 2. Then, in a state where the first ceramic molded body 1 and the second ceramic molded body 2 are covered with the shielding film 5, the first ceramic molded body 1 and the second ceramic molded body 2 are interposed through the shielding film 5. It is preferable that the first ceramic molded body 1 and the second ceramic molded body 2 are joined by pressurization with the pressurized liquid 24.

  Next, referring to FIG. 5, in the step of sintering the ceramic joined body (S <b> 40), the ceramic joined body 3 is heated inside the sintering furnace 31. Thereby, the ceramic joined body 3 is sintered. The ceramic joined body is heated with the shielding film 5 removed.

  As said shielding film 5, a vinyl bag and bag-shaped rubber | gum can be applied. In these cases, the shielding film 5 is preferably packed under reduced pressure in order to prevent molding defects and bag damage due to the encapsulated gas. Referring to FIGS. 6 and 7, shielding film 5 is formed in a bag shape having one open end, and first ceramic molded body 1 and second ceramic molded body 2 are accommodated in shielding film 5. . Then, the internal space 6 of the shielding film 5 is decompressed in a state where one end is sealed. Note that natural rubber (NR), nitrile rubber (NBR), or the like can be used as the material for the bag-shaped rubber.

  8 to 10, the shielding film 5 may be formed of a coating 51 formed by either dip coating or spraying of a material 42 that is made rubber by drying or heating. As the material 42 to be rubberized by either drying or heating, latex, liquid rubber, or the like can be applied. Silicon rubber, urethane rubber, or the like can be applied as a raw material for the material 42 that is made rubber by either drying or heating.

  Referring to FIG. 8, the first ceramic molded body 1 and the second ceramic molded body 2 bonded by the bonding material 4 are rubberized by either drying or heating accommodated in a container 41. Soaked in. Thereby, the material 42 is uniformly applied to the surfaces of the first ceramic molded body 1 and the second ceramic molded body 2. Referring to FIG. 9, the first ceramic molded body 1 and the second ceramic molded body 2 are moved out of the container 41, whereby a film 51 is formed by the material 42 applied to the surface. Thereby, the shielding film 5 made of the coating 51 is formed.

  Subsequently, with reference to FIG. 10, a mist-like material 42 is sprayed onto the surfaces of the first ceramic molded body 1 and the second ceramic molded body 2 bonded by the bonding material 4. Thereby, the film 51 similar to FIG. 9 is formed by the material 42 sprayed on the surface. Therefore, the shielding film 5 made of the coating 51 is formed.

  In addition, referring to FIGS. 11 and 12, when material 42 to be rubberized by either drying or heating is dipped and sprayed, the first ceramic molded body 1 and the second ceramic molded body are protected by a protective member. It is desirable to prevent the penetration of the material 42 into the two mutual joint portions (fitting portions) 7. Therefore, as shown mainly in FIG. 11, the protective member prevents the coating 51 formed of the material 42 from entering the joint portion 7 of the first ceramic molded body 1 and the second ceramic molded body 2. 8 is covering the joint 7. In this state, as shown mainly in FIG. 12, a film 51 is formed on the first ceramic molded body 1 and the second ceramic molded body 2. Thereby, the penetration of the material 42 into the joint portion 7 is prevented.

  Next, the effect of the manufacturing method of the ceramic joined body of one embodiment of the present invention will be described.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the ceramic joined body 3 is formed by fitting the first ceramic molded body 1 and the second ceramic molded body 2 using isotropic pressure molding. Each of the molding pressures when the first ceramic molded body 1 and the second ceramic molded body 2 are individually molded is lower than the molding pressure of isotropic pressure molding. The molding pressure of the first ceramic molded body 1 when molding the first ceramic molded body 1 and the second ceramic molded body 2 individually is lower than the molding pressure of the second ceramic molded body 2 and During the isostatic pressing, the second ceramic molded body 2 is fitted to the first ceramic molded body 1 to obtain the ceramic bonded body 3. For this reason, the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 are joined by the molding pressure at the time of isotropic pressure forming by isotropic pressure forming. As a result, the entire ceramic joined body 3 is molded at a molding pressure reached by isotropic pressure molding. Therefore, since the entire ceramic joined body 3 has a uniform pressure distribution, the shrinkage characteristics during sintering are also uniform. At the same time, the first ceramic molded body 1 having a low molding pressure is pressure-bonded to the second ceramic molded body 2 having a high molding pressure at the fitting portion. Therefore, it can suppress that a crack or peeling arises in a fitting part etc. when sintering.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the respective molding pressures when individually molding the first ceramic molded body 1 and the second ceramic molded body 2 are 5 MPa or more, And it is 2/3 or less of the molding pressure of isotropic pressure molding. The purpose of joining is to reduce the molding pressure when molding the first ceramic molded body 1 and the second ceramic molded body 2 individually to 2/3 or less of the molding pressure during isotropic pressure molding. Thus, it is possible to reliably obtain the effect of correcting the molded body equivalent to the molded body obtained by the isotropic pressure molding. And the 1st ceramic molded object 1 and the 2nd ceramic molded object by making each forming pressure at the time of forming the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 into 5 Mpa or more individually Each of the two can be easily retained. Moreover, it can suppress that the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 are damaged at the time of isotropic pressure forming.

  According to the method for manufacturing a ceramic joined body according to one embodiment of the present invention, the first ceramic molded body 1 and the second ceramic molded body 1 and the second ceramic molded body 1 are separately molded. The difference in molding pressure between the ceramic molded bodies 2 is 10% or more. A difference in molding pressure between the first ceramic molded body 1 and the second ceramic molded body 2 when the first ceramic molded body 1 and the second ceramic molded body 2 are individually molded is set to 10% or more. By this, the shrinkage | contraction difference resulting from the shaping | molding pressure difference of the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 can be enlarged, and the crimping effect | action of a fitting part can fully be generate | occur | produced.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the first ceramic molded body 1 and the second ceramic molded body 2 contain either oxide ceramics or non-oxide ceramics. Thereby, either oxide ceramics or non-oxide ceramics can be applied to the materials of the first ceramic molded body 1 and the second ceramic molded body 2.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the main components of the first ceramic molded body 1 and the second ceramic molded body 2 are the same. Thereby, even if additive materials, such as a sintering auxiliary agent and a dispersion reinforcement, differ a little, the ceramic joined body which can suppress that a crack or peeling arises by a fitting part etc. can be obtained when sintered.

  According to the method for manufacturing a ceramic joined body according to one embodiment of the present invention, the steps of individually forming the first ceramic molded body 1 and the second ceramic molded body 2 include a die press, a uniaxial rubber press, Forming at least one of the first ceramic molded body 1 and the second ceramic molded body 2 by one or more selected from the group consisting of isostatic pressing, extrusion molding, injection molding, and slip casting. It is out. Thereby, when forming the 1st ceramic molded object 1 and the 2nd ceramic molded object 2 separately, a wide shaping | molding method is employable. Further, the first ceramic molded body 1 and the second ceramic molded body 2 can be molded by different molding techniques.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the first ceramic molded body 1 and the second ceramic molded body 2 are bonded to each other with the bonding material 4 during the isotropic pressure forming. Are joined together. Since the first ceramic molded body 1 and the second ceramic molded body 2 are bonded to each other with the bonding material 4, the first ceramic molded body 1 and the second ceramic molded body 2 can be accurately combined.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the joining material 4 is made of a slurry having the same main component as the main components of the first ceramic molded body 1 and the second ceramic molded body 2. Become. Thereby, the intensity | strength of the junction part 7 can be made into the intensity | strength equivalent to the 1st ceramic molded object 1 and the 2nd ceramic molded object 2. FIG.

  According to the method of manufacturing a ceramic joined body according to the embodiment of the present invention, the isotropic pressure forming is performed by pressurizing the first ceramic molded body 1 and the second ceramic molded body 2 with the pressurized liquid 24. 1 is a wet cold isostatic pressing method in which a ceramic molded body 1 and a second ceramic molded body 2 are joined. Since the first ceramic molded body 1 and the second ceramic molded body 2 are pressurized with a pressurized liquid, a mold or jig matching the shape of the joined body is not required. Therefore, productivity can be improved.

  According to the method for manufacturing a ceramic joined body according to one embodiment of the present invention, the pressure liquid 24, the first ceramic molded body 1 and the second ceramic molded body 2 are subjected to wet cold isostatic pressing. In a state where the first ceramic molded body 1 and the second ceramic molded body 2 are covered by the shielding film 5 disposed therebetween, the first ceramic molded body 1 and the second ceramic molded body are interposed through the shielding film 5. By pressurizing the body 2 with the pressurized liquid 24, the first ceramic molded body 1 and the second ceramic molded body 2 are joined. For this reason, the first ceramic molded body 1 and the second ceramic molded body 2 can be protected from the pressurized liquid 24 by the shielding film 5.

  According to the method for manufacturing a ceramic joined body according to one embodiment of the present invention, the first ceramic molded body 1 and the second ceramic molded body 2 are formed in a bag shape having one end where the shielding film 5 is opened. Is housed in the shielding film 5 and the inner space 6 of the shielding film 5 is decompressed in a state where one end is sealed. Thereby, it is possible to suppress molding defects due to the gas contained in the internal space 6 and damage to the shielding film 5.

  According to the method for manufacturing a ceramic joined body according to one embodiment of the present invention, the shielding film 5 includes the coating 51 formed by either dip coating or spraying of a material that becomes rubber by either drying or heating. . Since the coating 51 adheres along the outer shape of the first ceramic molded body 1 and the second ceramic molded body 2, the shielding film 5 can be applied to a more complicated shape.

  According to the method for manufacturing a ceramic joined body of one embodiment of the present invention, the protective member 8 prevents the coating from entering the joint portion 7 of the first ceramic molded body 1 and the second ceramic molded body 2. Then, the coating 51 is formed on the first ceramic molded body 1 and the second ceramic molded body 2 in a state where the joint portion 7 is covered. Thereby, the penetration of the coating 51 into the joint portion 7 can be prevented.

Examples will be described below.
First, members 1 to 26 were created under the molding conditions shown in Table 1, respectively.

For each member, silicon nitride ceramics, alumina ceramics, or zirconia ceramics were used. Silicon nitride ceramics (90 mass% Si ₃ N ₄ -5 mass% Y-5 mass% Al, 90 mass% Si ₃ N ₄ -5 mass% La-5 mass% Al) have a main component of 90 mass% Si ₃ N ₄ (silicon nitride) and the auxiliary agent is 5 mass% Y (yttrium) -5 mass% Al (aluminum) or 5 mass% La (lanthanum) -5 mass% Al. The main component of alumina ceramics (100% by mass Al ₂ O ₃ ) is 100% by mass Al ₂ O ₃ (aluminum oxide). The main component of zirconia ceramics (95 mass% ZrO ₂ -5 mass% Y) is ZrO ₂ (zirconium oxide), and the auxiliary is 5 mass% Y.

  As a molding method of each member, a die press, a uniaxial rubber press, a cold isostatic press, extrusion molding, injection molding, and slip casting were used. The molding pressure (MPa) is the molding pressure of each member. The relative pressure (%) is the ratio of the molding pressure of each member to the pressure (300 MPa) of isotropic pressure molding at the time of joining described later. Whether or not molding is possible indicates that each member could be molded, and × indicates that each member could not be molded. The member 1 could not be molded because of a low molding density. On the other hand, members 2 to 26 could be molded.

  Next, the test piece will be described. For comparison, a test piece integrally formed by cold isostatic pressing (CIP) was prepared. Test pieces were prepared using silicon nitride ceramics, alumina ceramics, and zirconia ceramics, respectively.

  Next, comparative examples and examples of the present invention were created using the above-described members under the molding conditions shown in Table 2. After joining each said member by isostatic pressing, it sintered and the comparative example and the Example were created. That is, with reference to FIG. 13 and FIG. 14, the member A is the second ceramic molded body 2, and the member B is the first ceramic molded body 1. A slurry is used as the bonding material 4. The members A and B were joined through the slurry to produce a ceramic joined body 3. A cylindrical second ceramic molded body 2 is fitted to the inner peripheral side of the cylindrical first ceramic molded body 1.

  As a bonding method, a slurry having the same main component as the main components of the first ceramic molded body 1 and the second ceramic molded body 2 is applied, and the first ceramic molded body 1 and the second ceramic molded body 2 are applied. And glued together. A vinyl bag was used as the shielding film. The film thickness of the vinyl bag is 0.05 to 0.1 mm. The internal space of the vinyl bag was depressurized. Wet cold isostatic pressing (WET-CIP) was adopted for isostatic pressing. The pressure applied in wet cold isostatic pressing was 300 MPa. “Yes” indicates that the member A and the member B can be joined, and “x” indicates that the member A and the member B cannot be joined. Δ indicates that member A and member B could not be joined sufficiently.

  In Examples 1 to 3 in which the molding pressures of the members A and B before joining are lower than the molding pressure of isotropic pressure molding and the molding pressures of the members A and B before joining are different, the members A and B can be joined. It was. This is because a substantially uniform forming pressure is applied to a plurality of ceramic molded bodies processed under pressure forming by isotropic pressure forming for bonding, and is low by isotropic pressure forming for bonding at the fitting portion. This is thought to be due to the fact that the compact of the molding pressure has a larger volume shrinkage than the compact of the high molding pressure.

  In Comparative Example 1 in which the molding pressures of the members A and B before joining were less than 5 MPa, they could not be joined because they were damaged during isotropic pressurization. Further, in Comparative Example 2 in which the molding pressure of the members A and B before joining exceeds 2/3 of the molding pressure of isotropic pressure molding, the member A was easily pulled out from the member B after the isotropic pressure molding. This is because the pressure deviation and the directionality of the pressure that occur during the molding of the members A and B could not be corrected by the pressure at the time of joining, so they were joined in appearance but were not integrated. It is thought that.

  Further, in Example 4 in which the difference in molding pressure between the members A and B before joining was 10% or more, the members A and B could be joined. On the other hand, in Comparative Example 3 in which the difference in molding density between the members A and B before joining was 5%, the member A was easily pulled out from the member B after isotropic pressure molding. This is probably because the shrinkage difference due to the molding pressure difference did not sufficiently occur at the fitting portion during isotropic pressure molding, and the crimping action of the fitting portion did not occur sufficiently.

  In Examples 1 to 6, in which the main components of the members A and B are alumina and zirconia, which are oxide ceramics, and silicon nitride, which is a non-oxide ceramic, the members A and B can be joined together. Similar results can be obtained if the main components of members A and B are oxide ceramics such as alumina and zirconia, and non-oxide ceramics such as silicon nitride, silicon carbide and aluminum nitride.

  Further, in Comparative Examples 4 to 6 in which the main raw materials of the members A and B were different and the main components were different, the members A and B could not be joined. The reason for this is thought to be because the shrinkage characteristics of members A and B differ during sintering. Further, in Example 7 in which the auxiliary components of the members A and B before joining were different but the main components were the same, the members A and B could be joined.

  Further, in Examples 8 to 17 in which the difference in molding pressure between the members A and B before joining is 10% or more, a die press, a uniaxial rubber press, a cold isostatic press, extrusion molding, injection molding, The members A and B could be joined by molding methods with different slip casting.

  Next, the shape of the members A and B, the bonding method, and the shielding film were varied, and the possibility of joining and the strength of the column portion were examined. Comparative examples and examples of the present invention were prepared under the molding conditions shown in Table 3.

  The shapes of the comparative example and the example were the shapes shown in FIG. 14 and the shapes shown in FIGS. Referring to FIGS. 15 to 17, member A is the second ceramic molded body 2, and member B is the first ceramic molded body 1. A slurry is used as the bonding material 4. The members A and B were joined through the slurry to produce a ceramic joined body 3. A wedge-shaped second ceramic molded body 2 is fitted to the surfaces of the two annular first ceramic molded bodies 1 facing each other.

  As a bonding method, the members A and B were bonded with an adhesive or a slurry without a bonding material. As the shielding film, a vinyl bag or a film formed by dip coating was used. The inner space of the vinyl bag was reduced. In Example 19 and Example 21, the joint was sealed with a protective member. Wet cold isostatic pressing (WET-CIP) was adopted for isostatic pressing. After joining each member by isostatic pressing, it sintered and produced the comparative example and the Example. Whether or not joining is possible indicates that ◯ can join the members A and B, and × indicates that the members A and B cannot be joined. Δ indicates that member A and member B could not be joined sufficiently. The column portion strength (%) is a relative strength with respect to 100% strength of the machined part as a comparison target. The column strength (%) was measured as follows. In FIG. 16, the member 1 is grasped and pulled in the axial direction. The breaking strength at this time was defined as the column portion strength.

  In Comparative Example 9 in which the members A and B were bonded without a bonding material, bonding could not be performed. In Comparative Example 10 in which the members A and B were bonded with an adhesive, the member A was easily pulled out from the member B after isotropic pressure molding. On the other hand, in Example 18 in which the slurry containing the same main component as the members A and B was applied to the bonding surface, the members A and B could be bonded. The reason for this is considered to be that by using the slurry containing the same main component as the members A and B, the members and the bonding interface were integrated, and the same strength as that of the integrally molded product was obtained.

  Moreover, it was not able to join in the comparative example 11 which does not give a pressure reduction process. The reason for this is considered to be that if the decompression process is not performed, the vinyl bag appropriately follows the shape of the base of the column portion, and the entire member is not uniformly pressurized. In Example 20 in which the shielding films were formed by adhering the members A and B with a slurry and then immersed in a silicon rubber forming solution, they could be joined by performing WET-CIP treatment after drying (silicon rubber conversion). Separation of the joint surface was observed in some samples. The reason for this is considered to be that bonding is insufficient because the silicon rubber forming solution has permeated into the bonded portion (bonded surface). The thickness of the shielding film made of silicon rubber is 0.5 to 2.0 mm.

  On the other hand, in Example 19 and Example 21 in which a sealing tape (protective member) was wound around the joining surface and immersed in the silicon rubber forming solution, joining was possible, and no joining failure was observed. This is probably because the sealing tape prevented the silicon rubber forming solution from penetrating into the sample.

Further, in Comparative Example 12, the members A and B could not be sufficiently joined.
In Example 20, the column strength was 58.2%, and in Example 21, the column strength was 99.9%.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be particularly advantageously applied to a method for manufacturing a ceramic joined body in which a ceramic joined body is formed by joining ceramic shaped bodies.

  DESCRIPTION OF SYMBOLS 1 1st ceramic molded object, 2nd 2nd ceramic molded object, 3 Ceramics joined body, 4 Joining material, 5 Shielding film, 6 Internal space, 7 Joining part (fitting part), 8 Protection member, 42 Material, 51 Coating.

Claims (13)

Individually molding the first and second ceramic molded bodies made of the same kind of materials;
Forming a ceramic joined body by fitting the first and second ceramic shaped bodies using isotropic pressure molding; and
A step of sintering the ceramic joined body,
The molding pressure when molding the first and second ceramic molded bodies individually is lower than the molding pressure of the isotropic pressure molding, and the first and second ceramic molded bodies are molded individually. The molding pressure of the first ceramic molded body is lower than the molding pressure of the second ceramic molded body, and the second ceramic molding is applied to the first ceramic molded body during the isotropic pressure molding. A method for producing a ceramic joined body, wherein the ceramic joined body is obtained by fitting a body.   2. The molding pressure according to claim 1, wherein the molding pressure when molding the first and second ceramic molded bodies individually is 5 MPa or more and 2/3 or less of the molding pressure of the isotropic pressure molding. Manufacturing method of ceramic joined body.   The ceramic according to claim 1 or 2, wherein a difference in molding pressure between the first and second ceramic compacts when the first and second ceramic compacts are individually molded is 10% or more. Manufacturing method of joined body.   The manufacturing method of the ceramic joined body in any one of Claims 1-3 in which the said 1st and 2nd ceramic molded object contains either oxide ceramics or non-oxide ceramics.   The manufacturing method of the ceramic joined body in any one of Claims 1-4 whose main components of a said 1st and 2nd ceramic molded object are the same.   The step of individually molding the first and second ceramic molded bodies is one selected from the group consisting of a die press, a uniaxial rubber press, a cold isostatic press, extrusion molding, injection molding, and slip casting. The manufacturing method of the ceramic joined body in any one of Claims 1-5 including the process of shape | molding at least any one of the said 1st and 2nd ceramic molded object by the above.   The method for manufacturing a ceramic joined body according to any one of claims 1 to 6, wherein the first and second ceramic compacts are joined together with a joining material during the isostatic pressing.   The method for manufacturing a ceramic joined body according to claim 7, wherein the joining material is made of a slurry having the same main component as that of the first and second ceramic molded bodies.   The isotropic pressure forming is wet cold isostatic pressing in which the first and second ceramic compacts are joined by pressing the first and second ceramic compacts with a pressurized liquid. Item 9. A method for producing a ceramic joined body according to any one of items 1 to 8.   During the wet cold isostatic pressing, the first and second ceramic compacts are covered with a shielding film disposed between the pressurized liquid and the first and second ceramic compacts. The first and second ceramic molded bodies are bonded to each other by pressing the first and second ceramic molded bodies with the pressurized liquid through the shielding film in a state. Manufacturing method of ceramic joined body.   The shielding film is formed in a bag shape having one end opened, the first and second ceramic molded bodies are accommodated in the shielding film, and the one end is sealed, and the inside of the shielding film The method for producing a ceramic joined body according to claim 10, wherein the space is decompressed.   The method for manufacturing a ceramic joined body according to claim 10, wherein the shielding film is formed of a film formed by either dip coating or spraying of a material that is rubberized by either drying or heating.   In a state where the joint portion is covered with a protective member so that the coating film does not enter the joint portion between the first and second ceramic molded bodies, the coating film is on the first and second ceramic molded bodies. The manufacturing method of the ceramic joined body of Claim 12 formed in this.

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