JP3825116B2 - Ceramic firing method, ceramic firing apparatus and firing jig - Google Patents

Description

【００６２】
焼成後、型１３から取り出すときの荷重、型から取り出した焼成体の状態を表１に示す。また、焼成体とスペーサー２４Ａ、２４Ｂとの反応は、ほとんど見られないか、まったく見られなかった。
【００６３】
次に、上記と同様の手順に従って、比較実験を行った。ただし、図３における吸収体１６、１７、２２は設けず、吸収体１６の位置に、厚さ０．２５ｍｍの柔軟性黒鉛シート（グラファイトホイル）を設置した。また、原料の種類、焼結助剤の種類、焼結助剤の添加量、焼成工程における最高温度、最高温度での保持時間を、表２に示すように変更した。
【００６４】
【表２】

【００６５】
焼結助剤の添加量が３重量％以上である場合には、焼成後、型１３から焼成品を取り出すときの荷重は、いずれも２０トン以上が必要であり、かつ型抜き時にダイスが破損した。また、スリーブと焼成品とが激しく反応しており、かつ型から取り出した焼成品に欠けまたはクラックが見られた。
【００６６】
焼結助剤の添加量が０．１重量％である場合には、焼成後、型１３から焼成品を取り出すときの荷重は１０トン以下であり、焼成品に欠け、クラックが認められなかった。ただし、焼成品とスリーブとが一部反応していたので、スリーブの寿命が短くなることが判った。
【００６７】
【発明の効果】
以上述べたように、本発明によれば、セラミックスの未焼成物を加熱して焼成させるのに際して、未焼成物の加熱中にその外部へと浸出、拡散反応により物質移動してくる助剤成分等の排出物が、スリーブ等の焼成治具やパンチ等と反応するのを、効果的に防止できる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係るホットプレス装置を概略的に示す断面図である。
【図２】本発明の他の実施形態に係り、複数の未焼成物を同時に処理するためのホットプレス装置を概略的に示す断面図である。
【図３】本発明の更に他の実施形態に係り、複数の未焼成物を同時に処理するためのホットプレス装置を概略的に示す断面図である。
【図４】本発明の更に他の実施形態に係り、複数の未焼成物を同時に処理するためのホットプレス装置を概略的に示す断面図である。
【図５】（ａ）、（ｂ）は、図４のホットプレス装置の作用効果を説明するための模式的断面図である。
【図６】（ａ）、（ｂ）は、受け台やスリーブへの排出物、反応物等の付着や破損の状況を説明するための模式図である。
【符号の説明】
１，１１ 上パンチ、 １ａ，１１ａ 上パンチの加圧面、 ２，１２ 受け台、 ２ａ，１２ａ 受け台の加圧面、 ３，１３ 型、 ４Ａ，４Ｂ，１４Ａ，１４Ｂ，２４Ａ，２４Ｂ スリーブ、 ５，５Ａ，５Ｂ スペーサー、 ６，１６ 保持部材側吸収体、 ７，１７ 面状吸収体、 ８，１８Ａ，１８Ｂ，１８Ｃ，２８Ａ，２８Ｂ，２８Ｃ 未焼成物、 ８ａ，８ｂ，１８ａ，１８ｂ，２８ａ，２８ｂ 未焼成物の加圧面、 ８ｃ，１８ｃ，２８ｃ 未焼成物の非加圧面、 ２９ 非加圧面側吸収体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for firing various ceramics.
[0002]
[Prior art]
The press firing method of ceramics by the hot press method has been used for sintering various ceramics such as silicon nitride, silicon carbide, and aluminum nitride. For example, ferrite for magnetic heads, ferroelectric piezoelectric ceramics, transparent It is used to manufacture base materials for electronic materials such as photoceramics and translucent piezoelectric ceramics, and semiconductor manufacturing devices such as ceramic heaters, ceramic electrostatic chucks, ceramic high-frequency electrode devices, and ceramic susceptors.
[0003]
A ceramic hot press apparatus basically includes a pressurizing mechanism and a heating mechanism, and the pressurizing mechanism usually includes a pressing die and a punch. The material of the pressurizing mechanism is sufficient to withstand a predetermined pressure under a heating condition of the ceramic powder or the molded body, for example, at a temperature of 1000 to 2500 ° C., and the chemical reaction with the ceramic powder or the like. It is required not to cause. As such a material, for example, graphite is used in a vacuum or in an inert gas such as N ₂ or Ar. Further, since the dies and punches are required to have high dimensional accuracy, the manufacturing cost is high and expensive.
[0004]
However, in an actual hot press apparatus, a sleeve for holding a ceramic compact or powder, for example, is in close contact with or reacts with the ceramic raw material or sintering aid at high temperature and high pressure, or an upper punch, lower The punch sometimes adhered or reacted with the ceramic raw material or the sintering aid. In such a case, ceramics or a chemical reaction product thereof strongly reacts with the inner surface of the sleeve, the upper punch, and the lower punch. After hot pressing, a great deal of pressure is applied between the sleeve, upper punch, lower punch, etc., and the ceramics (fired product), so it is difficult to remove the fired product, as described above. Removal of the fired product has become more difficult due to the presence of a strong reaction product.
[0005]
This phenomenon is schematically shown in FIGS. 6A and 6B. For example, when the cradle 31 and the mold 32 are combined, the ceramic powder or the discharge 33 discharged from the molded body, or the reaction product 33 generated by the reaction with the material of the mold 32 is converted into the mold 32. It reacts with the inner surface 32a. Some of these discharges flow down along the inner surface of the mold 32 and reach the surface of the cradle 31 and the gap between the cradle 31 and the mold 32.
[0006]
The discharged product or reactant 33 not only makes it difficult to remove the fired product, but also when the discharged product or reactant 33 is removed, chipping occurs from the sleeve 32A or the cradle 31A as indicated by 34. Sometimes.
[0007]
As a result, when removing the fired product from the sleeve, the upper punch, the lower punch or the like, the sleeve or the like may be locally damaged. Also, chipping may occur when removing reactants such as ceramics and their chemical reaction products that have reacted strongly to the sleeve or the like. In such a case, since it is necessary to replace expensive firing jigs such as a sleeve, an upper punch, a lower punch, etc., this has caused an increase in the manufacturing cost of the fired product.
[0008]
In order to solve this problem, the present applicant, in Japanese Patent Application Laid-Open No. 5-318427, covers the inner surface of the sleeve and the surface in contact with the punch formed body with a heat-resistant foil piece such as graphite foil. Proposed that. This is an extremely effective method for preventing the product of the chemical reaction between the sleeve or punch and the ceramics or the ceramics from firmly attaching to the sleeve or the punches at high temperature and high pressure.
[0009]
[Problems to be solved by the invention]
However, even with this method, it has been found that problems still occur under the types of ceramics and under specific conditions. For example, when an auxiliary material such as Y ₂ O ₃ is contained in the ceramic raw powder or its molded product, the auxiliary agent or auxiliary component diffuses in the hot press sleeve and punch. May cause mass transfer.
[0010]
The auxiliary agent or auxiliary component diffused and transferred in this way reacts with a part of the graphite foil, and further reacts with a firing jig such as a sleeve or a punch, which becomes brittle and shortens the life. There was a thing. In addition, when the reaction between the auxiliary component and the firing jig is remarkable, it becomes difficult to take out the fired product from the firing jig such as a sleeve (unmolding), and in the worst case, the fired product is damaged. Or the punch and sleeve may be damaged.
[0011]
In particular, such a phenomenon is likely to occur when a sintering aid is contained in a raw material of a liquid phase sintered type ceramic such as aluminum nitride ceramics.
[0012]
The subject of the present invention is that when the ceramic unfired product is heated and fired, the effluent such as an auxiliary component that leaches out and diffuses to the outside during the heating of the unfired product and moves through the substance, It is to be able to effectively prevent a reaction with a firing jig such as a sleeve or a punch.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides:
When the ceramic unfired material is heated and fired, the ceramic material comprises at least one of fiber, felt, and cloth for absorbing the discharged material discharged from the unfired material while the unfired material is heated. A ceramic firing method comprising: an absorbent body having a form ; and a graphite foil, wherein the absorbent body is disposed on a surface in contact with the unfired material, and the graphite foil is disposed on the outside thereof. About.
[0014]
Further, the present invention provides a firing apparatus for heating and firing a ceramic unfired product, a fiber for absorbing exhaust discharged from the unfired product while heating the unfired product, An absorber having a form composed of at least one of felt and cloth; and a graphite foil; the absorber is installed on a surface in contact with the unfired product; and the graphite foil is installed outside the absorber. The present invention relates to a ceramic firing apparatus.
[0015]
The present invention is also a firing jig for the ceramic firing apparatus, wherein the unfired product is held inside the firing jig, and a pressing member can enter along the inner surface of the firing jig. Further, the present invention relates to a firing jig characterized in that a concave portion is provided on the inner surface at a lower portion of the firing jig where the unfired material is not disposed.
[0016]
The “unfired product” described in this patent specification includes all of powders, molded products, and calcined products.
[0017]
The present invention will be further described below with reference to the drawings as appropriate.
FIG. 1 is a cross-sectional view schematically showing an embodiment of a firing apparatus of the present invention. This baking apparatus is for hot pressing. In FIG. 1, sleeves 4 </ b> A and 4 </ b> B having a substantially semicylindrical shape are accommodated so as to contact the inner side surface 3 a of the mold 3. In the present embodiment, the sleeve is divided into two parts so that the fired product can be easily taken out from the mold 3 after firing. The sleeve can also be divided into three or more.
[0018]
The upper punch 1 can be moved toward the uniaxial direction (vertical direction in FIG. 1) along the inner surface 4a of the sleeves 4A and 4B. The cradle 2 is installed and fixed to a furnace body (not shown) below the sleeves 4A and 4B, and the pressurizing surface 1a of the upper punch 1 and the pressurizing surface 2a of the cradle 2 face each other. A space for hot pressing is formed. The upper punch 1 and the cradle 2 are pressing members as referred to in the present invention.
[0019]
A spacer 5 </ b> A is installed inside the pressure surface 1 a of the upper punch 1, and a spacer 5 </ b> B is installed inside the pressure surface 2 a of the cradle 2. The to-be-fired body 8 is accommodated between the spacers 5A and 5B. The body to be fired 8 is preferably a ceramic raw material powder or a pressure-molded body of powder, but may be a degreased body of this molded body.
[0020]
The planar absorbent bodies 7 are respectively installed between the pressure surface 8a and the spacer 5A of the body 8 to be fired and between the pressure surface 8b and the spacer 5B. Moreover, the absorber 6 is installed between the non-pressurized surface 8c of the to-be-fired body 8, and the inner surface 4a of sleeve 4A, 4B.
[0021]
Each of these absorbers 6 and 7 absorbs the auxiliary component and the like discharged from the non-fired product 8 as the sintering of the green product 8 proceeds, and the auxiliary component is directly in the sleeve. Avoid contact with 4A, 4B and spacers 5A, 5B. As a result, each fired product is firmly bonded to a firing jig such as the sleeve 4A, 4B, and the fired product cannot be taken out of the mold, or the sleeve is damaged when the fired product is removed from the sleeve 4A, 4B. Can be prevented.
[0022]
Such a firing method and apparatus can be applied to all ceramics, and particularly applicable to all ceramics containing a sintering aid. Examples of such ceramics include silicon nitride, aluminum nitride, alumina, silicon nitride-based composite material, aluminum nitride-based composite material, and alumina-based composite material. Examples of the sintering aid include rare earth elements such as Y ₂ O ₃ and Yb ₂ O ₃ and IIA group elements such as Ca and Mg.
[0023]
The present invention is particularly suitable for ceramics that undergo liquid phase sintering, such as aluminum nitride ceramics. Aluminum nitride ceramics undergo a sintering process called so-called liquid phase sintering. That is, a process in which the aluminum nitride particles once react with the auxiliary component and liquefy, then solidifies in the cooling process.
[0024]
In the aluminum nitride powder, usually 5% by weight or less of a sintering aid, for example, yttria is added and heated. At this time, the aluminum oxide phase on the surface of the aluminum nitride raw material powder reacts with a sintering aid such as Y ₂ O ₃ to produce yttrium aluminate, and liquid phase sintering proceeds. When carbon is used for the firing jig and fired in nitrogen for a long time, mass transfer occurs relatively easily due to the reduction and nitridation reaction by the carbon gas. Therefore, oxide is formed from the center of the sintered body toward the surface. It moves and is discharged from the inside of the sintered body to the outside.
[0025]
The amount of discharge of such sintering aids is quite large. For this reason, when only a non-reactive coating such as graphite foil is used, a considerable amount of sintering aid reacts toward the foil and the foil Seems to be easily broken. The present invention relates to a sintering process such as hot pressing by using an absorber disposed in the vicinity of the unfired product or in contact with the unfired product with a considerable amount of the sintering aid discharged from the unfired product. As it progresses, it is characterized by active absorption.
[0026]
Hereinafter, more specific embodiments will be described. The absorber used in the present invention is preferably made of a material that has a melting point equal to or higher than the firing temperature of the ceramic and does not substantially react with the ceramic. Such materials are preferably refractory metals that do not melt at the firing temperature, such as boron nitride and carbon, as well as molybdenum, tungsten, tantalum, niobium and hafnium.
[0028]
Moreover, the form of an absorber may be a fiber, felt, or cloth. Since the refractory metal powder is troublesome to handle, a flat plate made of a powder sintered body is preferable. In particular, an absorber made of a carbon material is preferable in that it has low reactivity with an aluminum nitride ceramic and is less likely to be an impurity, and carbon fiber, carbon felt, or carbon cloth is more preferable.
[0029]
As the holding member side absorbent body provided between the inner side surface of the holding member such as a sleeve and the non-pressurized surface 8c of the unfired product 8, any of powder, fiber, felt, and cloth can be used. On the other hand, as the absorber provided between the pressing surfaces 8a and 8b of the holding member 8 and the spacer, since powder is difficult to handle, fibers, felts, and cloth are preferable.
[0030]
When using a felt porous molded product, the bulk density is preferably 0.05 to 0.5 g / cm ³ . Moreover, it is preferable that the thickness shall be 0.5-20 mm.
[0031]
However, it is preferable to change the thickness of the felt according to the place of use and the amount of discharged matter.
[0032]
Specifically, when the amount of discharged matter is small, first, the felt wound around the outer periphery of the unfired body is dealt with, and the thickness can be reduced to 1 to 2 mm. At this time, particularly in the case of the furnace material configuration shown in FIGS. 1 to 3, it is preferable that the thickness of the felt is as thin as 1 to 2 mm from the viewpoint of reducing the generation of burrs. This may be a cross.
[0033]
If the amount of emissions is large and cannot be dealt with by this felt, the thickness of the felt can be increased. In this case, however, burrs may occur.
[0034]
When it is desired to prevent the generation of burrs, or when the thickness of the felt wound around the outer periphery of the green body cannot be dealt with even if the thickness is greater than 2 mm, the following (1) and (2) It is preferred to carry out one or both.
[0035]
(1) The furnace material configuration shown in FIG. 4 is adopted. In the case of the furnace material configuration of FIG. 4, since the generation of burrs can be suppressed, the thickness of the felt may be increased to 5 to 10 mm. (2) Place felt on top and bottom of the green product.
[0036]
As in (2), when felt is inserted between the spacer and the unfired material, and the unfired material is an embedded product such as an electrode (electrostatic chuck, plasma electrode built-in susceptor), use If the felt thickness is large, the thickness of the product film after firing is likely to vary, so the felt thickness is preferably 1 to 2 mm.
[0037]
If the discharge cannot be dealt with by these, the concave portion of the sleeve can be filled with felt. In this case, the thickness of the felt used is preferably 10 to 20 mm from the viewpoint of workability. This is because it can be set more easily than when thin felts are stacked.
[0038]
When using cross, having a basis weight better ones ^{150g / m 2 ~300g / m 2} , thickness 0.3~1mm is preferred. About use, what is necessary is just to handle like the said felt. In the case of cloth, although the absorption power is lower than felt, it does not pulverize even when loaded with a surface pressure of about 200 kg / cm ^2, so compared to felt pulverized with a surface pressure of about 30 g / cm ² , after firing It is easier to remove the product.
[0039]
FIG. 2 is a cross-sectional view schematically showing a hot press apparatus according to another embodiment of the present invention. Sleeves 14A and 14B are provided so as to contact the inner side surface 13a of the mold 13 of this apparatus. The inner surface 13a of the mold 13 is provided with a certain taper, and the inner surfaces 14a of the sleeves 14A and 14B extend straight from the upper side to the lower side in FIG.
[0040]
The cradle 12 is fixed to the lower side of the mold 13 and the sleeves 14A and 14B. In the sleeves 14A and 14B, four spacers 5 and three unfired products 18A, 18B, and 18C are accommodated between the upper punch 11 and the cradle 12. The spacer 5 is in contact with the pressure surface 11 a of the upper punch 11 and the pressure surface 12 a of the cradle 12.
[0041]
Between each spacer 5 and each pressing surface 18a, 18b of each unfired product 18A, 18B, 18C, a planar absorbent body 17 is interposed. Holding member side absorbers 16 are provided between the non-pressurized surfaces of the spacers 5 and the non-pressurized surfaces 18c of the unfired products and the sleeves 14A and 14B, respectively.
[0042]
According to such a hot press apparatus, in addition to the above-described effects of the present invention, a large number of fired products can be manufactured by a single hot press operation.
[0043]
However, when the firing process is actually carried out with this hot press apparatus, it has been found that there are the following problems. That is, when a plurality of, in some cases, 10 or more unfired materials are stacked and simultaneously subjected to hot pressing, a large amount of discharge such as the above-mentioned sintering aid is generated inside the mold. Most of these effluents or volatiles are absorbed by the absorbers 16 and 17, but under the condition that a large pressure is applied, the exhausts that could not be absorbed are the sleeves 14A and 14B and the unfired and It sometimes flowed down between the spacers and reached the cradle 12. This is because a large number of unfired materials are stacked and processed in a lump so that the amount of discharged matter is large.
[0044]
For this reason, the present inventor, in a firing jig (sleeve etc.) in which at least one pressing member (upper punch or lower punch etc.) can enter, It was conceived to provide a recess on the inner surface of the firing jig. And in this recessed part, the absorber for absorbing the discharge | emission discharged | emitted from an unbaked thing while heating an unbaked thing was installed.
[0045]
3 and 4 are sectional views schematically showing a hot press apparatus according to this embodiment of the present invention. However, the same members as those shown in FIG.
[0046]
In the apparatus of FIG. 3, step portions or recesses 21 are formed in the lower portions of the inner surfaces 24a of the sleeves 24A and 24B that do not contact the unfired product. Each recess 21 is close to the cradle 12. Each concave portion 21 is filled with an absorber 22, and each concave portion absorber 22 is in contact with the holding member side absorber 16.
[0047]
Exhaust discharged from each unfired material, flowing down the gaps between the sleeves 24A, 24B, each unfired material and the spacer 5, and not absorbed by the holding member side absorber 16 is absorbed by the absorbent 22 in the recess. The Accordingly, it is possible to prevent the discharged material from directly contacting and reacting with the cradle 12.
[0048]
Also in the apparatus of FIG. 4, the spacers 5 and the unfired products 28 </ b> A, 28 </ b> B, 28 </ b> C are alternately stacked, and the pressurization surfaces of the spacers 5 are the pressurization surfaces of the unfired products 28 </ b> A, 28 </ b> B, 28 </ b> C. 28a and 28b are in contact. In the present embodiment, the size of each green product 28A, 28B, 28C is made smaller than the size of each spacer 5, and the non-pressurized surface 28c of each green product 28A, 28B, 28C and the holding member side absorber 16 are set. A space was formed between them. And in this space, the non-pressurized surface side absorber 29 was installed so that each unbaked thing might be surrounded.
[0049]
The effects obtained by such a configuration will be described. In the apparatus as shown in FIG. 2 and FIG. 3, the dimensions of the spacers 5 and the dimensions of the unfired products are substantially the same. When each unfired product is fired under these conditions, so-called “burrs” may occur at the corners of the fired product.
[0050]
For example, as schematically shown in FIG. 5, the size of the unfired product 18A (18B, 18C) substantially coincides with a virtual line A indicating the size of a spacer (not shown). In this state, when the pressure is applied in the vertical direction in FIGS. 2 and 3, the components constituting the unfired product are plastically deformed together with the shrinkage when the temperature is higher than the liquid phase generation temperature in the firing process, and a part of the unfired product is formed. It is pushed out toward the corner. As a result, “burrs” or small protrusions 30a are generated at the corners of the fired product 30 shown in FIG.
[0051]
On the other hand, as shown in FIG. 4, by providing the non-pressurized surface side absorbent body 29 in the space between each unfired product 28A, 28B, 28C and the absorbent body 16, the “burr” as described above. We have succeeded in effectively preventing the occurrence of This is because, as schematically shown in FIG. 5B, the dimensions of the unfired products 28A, 28B, and 28C (represented by imaginary line B) are smaller than the dimensions of the spacer (represented by imaginary line A). An absorber 29 is installed in a space generated by the difference.
[0052]
At the time of hot pressing, when the unfired product reaches the liquid phase generation temperature or higher in the firing process, it is plastically deformed with shrinkage and spreads toward the sleeves 24A and 24B to produce a fired product 30A. That is, the size of the fired product 30A is larger than the size of the unfired product, and approaches the virtual line A. However, the expansion of the dimension in the radial direction is stopped by the action of the absorber 29 in the gap, and the constituent material of the unfired material does not enter the gap between the non-pressurized surface of the spacer 5 and the inner side surface 24a of the sleeve 24A, 24B. Therefore, the occurrence of “burrs” is prevented.
[0053]
【Example】
Hereinafter, more specific experimental results will be described.
(Experiment 1)
Firing experiments were performed using the hot press apparatus shown in FIG. As a ceramic raw material, a disk-shaped formed body 8 of aluminum nitride powder containing 5% by weight of yttria with respect to 100% by weight of AlN was used. This molded body had a diameter of 45 mm and a thickness of 30 mm. The pressure surface 2a of the cradle 2 has a diameter of 50 mm, and a graphite foil having a thickness of 0.25 mm is placed thereon via a spacer 5B. A carbon felt sheet having a thickness of 0.7 mm is placed on the graphite foil as the absorber 7. The disc-shaped molded body 8 was placed on the absorber 7.
[0054]
A sheet of carbon felt having a thickness of 2 mm is placed on the disk-shaped molded body 8 as the absorbent body 7, and a graphite foil having a thickness of 0.25 mm is placed thereon, and the upper punch 1 is placed thereon via a spacer 5 </ b> A. I put it.
[0055]
High-purity carbon powder having an average particle size of 500 μm and an ash content of 20 ppm or less is filled between the non-pressurized surface 8c of the disk-shaped molded body 8 and the inner surface 4a of the sleeves 4A and 4B so as to have a thickness of about 2.5 mm. And it was set as the holding member side absorber 6. FIG. In this example, high-purity carbon was used. However, when there is no influence on the product, carbon containing about 0.1% ash may be used.
[0056]
In this state, the compact was hot pressed. At this time, it was held for 4 hours while applying a pressure of 200 kg / cm ² at a maximum temperature of 1850 ° C. under a nitrogen atmosphere of 1.5 atm.
[0057]
As a result, no yttria component leached into the sleeve or the like, and the fired product could be easily taken out from the mold 3. The carbon powder 6 filled around the molded body absorbed yttria and was baked and hardened, but the reaction of the yttria component to the sleeve side was not reached. The average strength of the fired body thus obtained was 420 MPa, the average bulk density was 3.36 g / cc, and good results were obtained.
[0058]
(Experiment 2)
Using the hot press apparatus shown in FIG. 3, a firing experiment was performed. The molded body had a diameter of 240 mm and a thickness of 50 mm. The inner diameters of the sleeves 24A and 24B were 244 mm. However, the inner diameter of the sleeve recess 21 was 257 mm. The diameter of the pressing surface 12a of the cradle 12 and the diameter of the spacer 5 were 244 mm.
[0059]
A felt having a thickness of 2 mm was used as each planar absorber 17. As the absorber 22 in the recess 21, a ring-shaped felt having an outer diameter of 57 mm, an inner diameter of 244 mm, and a thickness of 6.5 mm was used. The type of the holding member side absorber 16 was changed as shown in Table 1.
[0060]
Ten unfired products 18A and the like were stacked. The raw material of each unfired product, the sintering aid, and the addition amount of the sintering aid were changed as shown in FIG. The firing pressure was 200 kg / cm ² , and the maximum temperature in the firing step and the holding time at the maximum temperature were changed as shown in Table 1, respectively.
[0061]
[Table 1]

[0062]
Table 1 shows the load when taking out from the mold 13 after firing, and the state of the fired body taken out from the mold. Further, the reaction between the fired body and the spacers 24A and 24B was hardly seen or not seen at all.
[0063]
Next, a comparative experiment was performed according to the same procedure as described above. However, the absorbers 16, 17 and 22 in FIG. 3 were not provided, and a flexible graphite sheet (graphite foil) having a thickness of 0.25 mm was installed at the position of the absorber 16. In addition, as shown in Table 2, the type of raw material, the type of sintering aid, the addition amount of the sintering aid, the maximum temperature in the firing step, and the holding time at the maximum temperature were changed.
[0064]
[Table 2]

[0065]
When the amount of sintering aid added is 3% by weight or more, the load when taking out the fired product from the mold 13 after firing must be 20 tons or more, and the die breaks during die cutting. did. Further, the sleeve and the fired product reacted vigorously, and the fired product taken out from the mold was chipped or cracked.
[0066]
When the additive amount of the sintering aid was 0.1% by weight, the load when the fired product was taken out from the mold 13 after firing was 10 tons or less, the fired product was chipped, and no cracks were observed. . However, since the fired product and the sleeve partially reacted, it was found that the life of the sleeve was shortened.
[0067]
【The invention's effect】
As described above, according to the present invention, when an unsintered ceramic product is heated and fired, the auxiliary component leaches out to the outside during the heating of the unsintered product and moves through a diffusion reaction. It is possible to effectively prevent the discharge product such as a sleeve from reacting with a firing jig such as a sleeve or a punch.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a hot press apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically showing a hot press apparatus for simultaneously processing a plurality of unfired products according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view schematically showing a hot press apparatus for simultaneously processing a plurality of unfired products according to still another embodiment of the present invention.
FIG. 4 is a cross-sectional view schematically showing a hot press apparatus for simultaneously processing a plurality of unfired products according to still another embodiment of the present invention.
5A and 5B are schematic cross-sectional views for explaining the operational effects of the hot press apparatus of FIG.
FIGS. 6A and 6B are schematic diagrams for explaining the state of attachment and breakage of discharged substances, reactants, and the like to the cradle and the sleeve. FIGS.
[Explanation of symbols]
1,11 upper punch, 1a, 11a upper punch pressure surface, 2,12 cradle, 2a, 12a cradle pressure surface, 3,13 type, 4A, 4B, 14A, 14B, 24A, 24B sleeve, 5, 5A, 5B Spacer, 6, 16 Holding member side absorber, 7, 17 Planar absorber, 8, 18A, 18B, 18C, 28A, 28B, 28C Unfired product, 8a, 8b, 18a, 18b, 28a, 28b Pressurized surface of green product, 8c, 18c, 28c Non-pressurized surface of green product, 29 Non-pressurized surface side absorber

Claims (13)

When the ceramic unfired material is heated and fired, the ceramic material comprises at least one of fiber, felt, and cloth for absorbing the discharged material discharged from the unfired material while the unfired material is heated. A ceramic firing method comprising: an absorbent body having a form ; and a graphite foil, wherein the absorbent body is disposed on a surface in contact with the unfired material, and the graphite foil is disposed on the outside thereof. .   2. The ceramic firing method according to claim 1, wherein the absorber is made of a material having a melting point equal to or higher than a firing temperature of the ceramic and does not substantially react with the ceramic. 3. The ceramic firing method according to claim 2, wherein the absorber is made of at least one material selected from the group consisting of carbon fiber, carbon felt, and carbon cloth . In a firing apparatus for heating and firing a ceramic unfired material, at least one of fibers, felts, and cloth for absorbing discharge discharged from the unfired material while heating the unfired material A ceramic comprising: an absorber exhibiting a form composed of seeds; and a graphite foil, wherein the absorber is installed on a surface in contact with the unfired product, and the graphite foil is installed outside the absorber. Firing equipment. A firing apparatus for firing the green product by pressurizing and heating, a pair of pressing members for pressurizing the green product, and a holding member for holding the green product A holding member into which at least one of the pressurizing members can enter along the inner side surface of the holding member, and between the inner side surface of the holding member and the non-pressurized surface of the unfired material. The ceramic firing apparatus according to claim 4 , wherein a holding member side absorber is provided as the absorber . The ceramic firing apparatus according to claim 5, wherein the holding member side absorber has a thickness of 0.3 mm to 2 mm. In the lower part of the holding member where the unfired product is not disposed, a concave portion is provided on the inner side surface, and an in-recessed absorbent body is provided as the absorbent body in the concave portion. The ceramic firing apparatus according to claim 5 or 6 . The ceramic firing apparatus according to claim 7, wherein the thickness of the absorber in the recess is 10 to 20 mm. A plurality of the unfired materials are accommodated in the holding member, and a planar absorbent body is interposed between the unfired materials as the absorbent body. The ceramic firing apparatus according to claim 1. 10. The ceramic firing apparatus according to claim 9, wherein a thickness of the planar absorber is 0.3 mm to 2 mm. Among the holding members, the unfired material and the spacer are alternately laminated, and the planar absorbent body is interposed between each unfired material and each spacer, and each of the spacers holds the holding material. A gap is provided between the non-pressurized surface of each unfired product and the holding member-side absorber, and is in contact with the member-side absorbent body. The ceramic firing apparatus according to claim 9 or 10 , wherein a side absorber is provided.   The ceramic firing apparatus according to claim 11, wherein the non-pressurized surface side absorber has a thickness of 5 to 10 mm. A firing jig for a ceramic firing apparatus according to any one of claims 7 to 12 , wherein the unfired product is held inside the firing jig and applied along an inner surface of the firing jig. A firing jig, wherein a pressing member can enter, and a concave portion is provided on the inner surface at a lower portion of the firing jig where the unfired material is not disposed.

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