JPH046181A - Production of circular opening forming ceramics sintered body - Google Patents

Abstract

PURPOSE:To obtain the circular opening ceramics sintered body without having the sintering residues remaining in the circular openings by embedding metallic materials coated with coating materials consisting of thermally decomposable or sublimatable materials into a ceramics green molding and sintering the resulted metal-inserted composite, then eluting the metallic materials in the sintered body. CONSTITUTION:The metallic materials 1 coated with >= 1 kinds of the coating materials 2 selected form the group consisting of the org. materials which are thermally decomposed at the temp. lower than the thermal decomposition initiation temp. of org. binders, the sublimatable materials which are sublimated at the temp. lower than the thermal decomposition initiation temp. of the org. binders and the evaporatable materials which are decomposed at the temp. higher than the thermal decomposition initiation temp. of the org. binders with the thickness thicker than the size of sintered shrinkage of the ceramics green molding 3 are embedded into the ceramics green molding 3 consisting of a ceramic material and an org. binder, by which the metal-inserted composite is formed. The metal composite sintered body (7: ceramics sintered body, 6: circular opening) is then formed by calcining the metal- embedded composite and further only the metallic materials 1 are eluted from this metal composite sintered body (8: circular opening).

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a sintered pore-forming ceramic body, and more specifically to a method for producing a sintered pore-forming ceramic body in which sintering residues do not remain in the pores. Concerning a method of manufacturing a body.

(Prior art) As a method for manufacturing a pore-forming ceramic sintered body,
For example, there is a method as described in Japanese Patent Application Laid-Open No. 63-99955. This manufacturing method involves forming a pattern with a photopolymerizable photosensitive resin, sandwiching this pattern between ceramic green sheets and laminating them together, and firing this laminate to cause the resin pattern to disappear by thermal decomposition. , a pore-forming ceramic sintered body is obtained.

Furthermore, Japanese Patent Application Laid-Open No. 63-4959 discloses a ceramic inkjet head in which an ink flow path is formed using a photosensitive resin sheet in the same manner as described above.

When producing a pore-forming ceramic sintered body using the above method, the thermal decomposition temperature of the pattern of the cured photopolymerizable photosensitive resin is higher than that of the organic binder of the green sheet. The organic binder in the green sheet will thermally decompose first. If the organic binder in the green sheet is thermally decomposed first in this way, by the time the photosensitive resin pattern is thermally shrunk, the matrix ceramic powder has not yet started sintering shrinkage and is in a very brittle state. Therefore, as the pattern shrinks, the ceramic powder around the pattern is peeled off. Therefore, the resulting pore-forming ceramic sintered body has the problem that sintering residue having the same composition as the matrix ceramic remains inside the pores.For example, in the case of the above ceramic inkjet head, this sintering residue remains. There was a drawback that the ink was easily clogged by the residue.

(Problems to be Solved by the Invention) The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a pore-forming ceramic sintered body in which no sintering residue remains in the pores. 1 target.

(Means for Solving the Problems) The ceramic green molded body used in the present invention is made of a ceramic material and an organic binder, and if necessary, ethyl alcohol, isopropyl alcohol, methyl ethyl alcohol, toluene, etc. After adding an organic solvent and kneading with a kneading machine such as a hall mill or vibration mill, it is formed by a molding method such as casting with a doctor blade, injection molding, extrusion molding, or compression molding.

Examples of the above ceramic materials include aluminum
Powders such as zirconia, magnesia, sialon, spinel, mullite, crystallized glass, silicon carbide, silicon nitride, aluminum nitride, and MgO-302-CaO system, B
2O3-3i02 system, Pb08203 5iC12 system, CaO3i02-CaO31O2- system, PbO-3
Glass frit powders such as i02-8203-CaO-based powders are mentioned, and two or more types of powders are used.

Examples of the organic binder include polyvinyl butyral, polyvinyl alcohol, polymethyl methacrylate-1
- Polymer materials such as polybutyl methacrylate, cellulose, dextrin, polyethylene wax, starch, and casein are used alone or in combination of two or more. Furthermore, a plasticizer such as dioctyl phthalate, dibutyl phthalate, polyethylene glycol, etc. may be added as necessary.

The metal materials used in the present invention are not particularly limited as long as they can be eluted, and examples include aluminum, copper, iron, silver, chromium, manganese, cobalt, nickel, gold, molybdenum, vanadium, Examples include metals such as titanium, alloys thereof, and the like.The shape thereof is not particularly limited, and for example, it is used in the shape of linearized foil, plate-shaped body, etc. Furthermore, if a specific shape is required, it may be produced by, for example, punching out a foil or a plate-like material, or etching it.

The coating material used in the present invention includes an organic material that thermally decomposes at a temperature lower than the thermal decomposition starting temperature of the organic binder, a sublimable material that sublimes at a lower temperature than the thermal decomposition starting temperature of the organic binder, and the organic binder. One or more types selected from the group consisting of volatile materials that decompose at a higher temperature than the thermal decomposition end temperature of .

The above-mentioned organic material is not particularly limited as long as it is thermally decomposed at a temperature lower than the thermal decomposition start temperature of the organic binder, and examples thereof include paraffin wax, microcrystalline wax, polymethylstyrene 1, positive butylene, and polystyrene. etc. can be mentioned. In particular, when the organic binder is polyvinyl butyral, paraffin wax, microcrystalline wax, etc. are suitable.

The above-mentioned sublimable material is not particularly limited as long as it is a solid that sublimes at a temperature lower than the thermal decomposition initiation temperature of the organic binder, and examples thereof include naphthalene, benzoic acid, anthraquinone, anthranilic acid, isophthalonitrile, 23- Published by Dichloro, 4~naphthoquinone, α-naphthol, p
-phenylphenol p-nitrophenol and the like.

The above-mentioned vaporizable material may be one that thermally decomposes at a higher temperature than the thermal decomposition end temperature of the organic binder described in 1.I, but it is preferable to use a material that decomposes and vaporizes without melting. For example,
Examples include carbon powders such as graphite and glassy carbon, and powders of melamine, polyimide, isophthalic acid, terephthalic acid, and tetrafluoroethylene resin.

Although the above-mentioned coating material is coated with a metal material, a small amount of a polymeric binder may be added to improve the coating strength of the coating material.

The polymer binder is not particularly limited as long as it is thermally decomposed at a lower temperature than the thermal decomposition initiation temperature of the organic binder, and examples thereof include polymethyl methacrylate, polybutyl methacrylate, ethyl cellulose, carboxymethyl cellulose, Examples include polyvinyl alcohol, starch, etc. The amount added depends on the strength of the coating material.
It may be determined as appropriate. If the amount added is too small, the reinforcing effect will be lost, and if it is too large, it will not be easy to decompose and vaporize the coating material.
0.01 to 5 parts by weight is preferred.

Any method may be used to coat the metal material with the coating material. For example, the coating material may be coated with methyl alcohol, ethyl alcohol, butyl alcohol, alcohol, isopropyl alcohol, cyclohexanol, terpineol, methyl ethyl ketone, acetone, or ethyl acetate. , A method in which a metal material is immersed in a coating liquid dissolved or dispersed in a solvent such as toluene, xylene, benzene, hexane, carbon tetrachloride, water, etc., pulled up and then dried, and a method in which the coating liquid is sprayed and then dried. Examples include methods. In addition,
If necessary, the above operation may be repeated multiple times to obtain the desired thickness.

The present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the metal buried composite, and FIG.
FIG. 3 is a cross-sectional view showing the state after the metal buried composite has been degreased, FIG. 3 is a cross-sectional view of the metal composite sintered body obtained by firing, and FIG. FIG. 2 is a cross-sectional view of a pore-formed ceramic sintered body obtained by the above-mentioned method. In FIG. 1, 1 is a metal material, and a coating material 2 is coated around it. 3 is a ceramic green molded body.

The first step in the present invention is to embed the metal material coated with the above-mentioned coating material in a ceramic green molded body,
This is a process of forming a metal buried composite. The method of embedding the metal material in the ceramic green molded body is not particularly limited, and examples include a method of sandwiching the metal material between multiple ceramic green sheets and bonding them under heat, and a method of embedding the metal material in the ceramic green molded body, and a method of embedding the metal material in a ceramic green molded body, and a method of embedding the metal material in a ceramic green molded body. A method in which a metal material is placed inside and pressure-molded, a casting method in which a metal material is held in a mold such as a plaster mold, and a ceramic slurry is poured around it are employed as appropriate.

The coating thickness of the coating material coated on the metal material is set to be greater than or equal to the sintering shrinkage dimension calculated from the sintering wire shrinkage rate of the ceramic green molded body 3. The upper limit of the coating thickness is not particularly limited, but if it becomes too thick, it becomes difficult to decompose and vaporize the coating material, so it is preferably equal to or smaller than the diameter of the metal material.

That is, in FIG. 1, if the diameter of the metal material 1 is r and the sintering wire shrinkage rate of the ceramic green molded body 3 is 1%,
The relationship between the sintering shrinkage dimension of the ceramic green molded body and the coating thicknesses d5 and d2 in the portion occupied by the coating material 2 is expressed by the following equation.

(dt +d2)≧(r+d, +d2) X (x/
100) Therefore, if r = 80 μm and x = 20%, the thickness of coating material 2 (dl + d2) is 20 μm
Therefore, the upper limit is 80 μm. It is desirable that the coating thickness be made as uniform as possible, and d and d2 are each formed to be approximately equal to 10 μm or more.

The metal buried composite body in which the metal material 1 is buried in the state shown in FIG. 1 is then fired to form a metal composite sintered body. Firing consists of a degreasing process and a firing process, and the coating material 2 disappears through thermal decomposition, sublimation, or decomposition and vaporization during firing, and voids 5 are formed between the ceramic degreased body 4 and the metal material l (
Figure 2).

When the coating material 2 is made of the organic material or sublimable material, the voids 5 are formed by thermal decomposition or sublimation at a temperature lower than the thermal decomposition temperature of the organic binder in the ceramic green molded body 3, that is, during the degreasing process. When the coating material 2 is formed of the vaporizable material, at a temperature higher than the thermal decomposition temperature of the organic binder in the ceramic green molded body 3,
That is, when heated after the degreasing step, the material is decomposed and vaporized to form the voids 5. In either case, the ceramic material in the ceramic green molded body 3 around the void 5 does not invade into the void 5.

The scattering conditions and degreasing conditions for the coating material 2 are appropriately determined depending on the type of organic binder in the coating material 2 and the ceramic green molded body 3, but when the coating material 2 is the above-mentioned organic material or sublimable material, After holding at the thermal decomposition temperature or sublimation temperature of the coating material 2 for 5 to 30 hours to scatter the coating material 2, the temperature is raised to 1 to b and held at that temperature for 1 to 5 hours to degrease. is desirable, and when the coating material 2 is the above-mentioned vaporizable material, 1-b The temperature is raised to 280-700 ° C., and after degreasing by holding at that humidity for 1-10 hours, the decomposition vaporization temperature of the coating material 2, For example, it is desirable to raise the temperature to 850°C and maintain it at that temperature for 5 to 30 hours. Note that this degreasing step may be performed under reduced pressure, and if the oxidation of the metal material 1 progresses and elution of the metal material 1 becomes difficult, degreasing may be carried out in a reducing atmosphere such as nitrogen or alcon.

Next, by firing, a metal composite sintered body containing the metal material 1 is obtained (FIG. 3). The firing conditions are appropriately determined depending on the type of the ceramic material, but are
It is desirable to raise the temperature to 600-1850°C at a heating rate of ~300°C/hr and maintain that temperature for 1-5 hours. Note that even if the firing temperature is higher than the melting point of the metal material 1, it is possible because the molten metal material 1 will solidify upon cooling. However, since the melt of the metal material 1 and its vapor may diffuse into the ceramic during sintering, it is preferable to perform the firing at a temperature lower than the melting point of the metal material 1.

In this firing step as well, if oxidation of the metal material 1 progresses, it is preferable to perform the firing in a reducing atmosphere as in the case of the degreasing step.

By the way, as is clear from the above, the void 5 shown in FIG. 2 has a size larger than the sintering shrinkage dimension of the ceramic degreased body 4 (ceramics green molded body 3). Accordingly, the void 5 decreases and a void 6 is formed. If the size of the void 5 and the sintering shrinkage dimension are matched, the void 5 will disappear and the void 6 will not be formed, but at least the surface of the ceramic sintered body 7 in contact with the metal material 1 is Since the unevenness is comparable to that of a primary particle, the voids 6 exist, although they are small.

Next, after cooling the ceramic sintered body 7 containing the metal material 1, the metal material 1 is eluted to obtain the ceramic sintered body 7 having holes 8 (FIG. 4). Although any method may be used for this elution, it is preferable to elute using a metal solution that can dissolve the metal material 1.

As the metal solution for eluting the metal material described in 2.2, a solution having solubility for the metal material used may be appropriately selected from solutions such as acids, alkalis, cyanide salts, and peroxides. For example, Hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, aqua regia, selenic acid, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous sodium cyanide solution, aqueous potassium cyanide solution, hydrogen peroxide solution, etc. (single or two or more) Both are used together.

Suitable combinations of the metal material 1 and the metal solution include, for example, an aqueous solution of aluminum and sodium hydroxide, a mixed acid of copper, sulfuric acid, and nitric acid, iron and hydrochloric acid, etc. If necessary, heat, pressurize, Auxiliary means such as ultrasonic vibration may also be used.

In addition, in the elution step, the metal-degrading solution enters into the void 6 and dissolves the linear metal material 1.

(Function) Since the method for manufacturing the pore-forming ceramic sintered body of the present invention is as described above, when a coating material consisting of an organic material and a sublimable material is used, the organic binder in the ceramic green molded body is Before thermal decomposition begins, the coating material thermally decomposes or sublimates to form voids, so at this point the ceramic material is strongly bound by the organic binder, and the ceramic material around the voids collapses, forming voids. It doesn't go inside. In addition, when a coating material made of a vaporizable material is used, the coating material decomposes and vaporizes after the thermal decomposition of the organic binder in the ceramic green molded body and voids are formed, so the ceramic material is fixed at this point. A ceramic degreased body is formed that is in a state of
The ceramic material around the void will not collapse and enter the void. Therefore, if the metal material in the metal composite sintered body is eluted after firing, it is possible to obtain a pore-formed ceramic sintered body in which no sintered residue of the ceramic material remains in the pores in any case.

When using the above metal material as a core material for forming pores, if the metal material is processed into a desired shape by punching, etching, etc., pores of any shape and size can be formed. .

In addition, when only the above-mentioned metal material is buried in a ceramic gellin molded body, degreased, and fired, the ceramic material contracts during sintering, whereas the metal material expands thermally, so the resulting metal composite sintered body is cracked. However, if the metal material is covered with a coating material, the sintering shrinkage of the ceramic material can be compensated for by the voids formed by the decomposition and vaporization of the coating material, so metal composite sintering without a crank is possible. You can get a solid body.

The reason for leaving voids in the metal composite sintered body is to allow the metal solution to easily penetrate into the metal composite sintered body when the metal material is eluted with a metal solution, and as a result, the metal material elution is prevented. done efficiently.

(Example) Hereinafter, an example of the method for manufacturing a pore-forming ceramic sintered body of the present invention will be described.

Note that "parts" means "parts by weight."

Example 1 Alumina powder (average particle size 3 μm) 40 parts P b
o S r 02 B203 System strength glass frit powder 60 parts (uniform particle size 5 μm, yield point 479°C) Polyvinyl butyral 12 parts Dioctyl phthalate 4.5 parts Methyl ethyl ketone 24 parts Toluene
18 parts isopropyl alcohol
18 parts of the above ceramic composition was kneaded in an alumina ball mill for 24 hours and coated on a polyethylene terephthalate film to produce a ceramic green sheet with a thickness of 400 μm.

This green sheet was heated to 640°C at a rate of 25°C/hr.
After being held for 2 hours, the sintered wire was cooled and the shrinkage rate of the sintered wire was measured and found to be 11.6%.

Next, paraffin wax (melting point 6) was added to 90 parts of benzene.
An aluminum wire with a length of 50 mm and a diameter of 250 μm is immersed in the coating liquid obtained by dissolving 8°C) on a 40°C hot water bath, and the aluminum wire is pulled out and dried. A paraffin wax coating with a total thickness of 40 μm was formed.

Said green sheet (50x 50 x 0.5 y
10 aluminum wires coated with the above paraffin wax are arranged at intervals of 2n+m on top of the above paraffin wax, and the mixed wire of the ceramic composition is applied thereon, dried, and then cut in a direction perpendicular to the aluminum wires to coat them. Metal buried complex with built-in aluminum wire (50 x 3 x 1 m
m) was obtained.

This metal buried composite was supplied to a heating furnace and heated to a temperature of 2.5'C/
The temperature was raised to 175°C at a heating rate of 2.5°C/h and held for 10 hours to decompose the paraffin wax film.
The temperature was raised to 450° C. at a heating rate of r and held for 2 hours to degrease. Further, the temperature was raised to 640°C at a rate of 50°C/hr and held for 2 hours to obtain a metal composite sintered body containing an aluminum wire.

Next, this metal composite sintered body was cooled to room temperature, immersed in a 6N sodium hydroxide solution for 48 hours, then taken out, and further immersed in a mixed acid consisting of 300 ml of hydrochloric acid, 300 ml of distilled water, and 20 ml of hydrogen peroxide, This was heated to 40° C. and the aluminum wire was eluted while applying ultrasonic vibration to obtain a pore-forming ceramic sintered body.

The obtained pore-formed ceramic sintered body has 10 pores with a diameter of 254 to 258 μm communicating from one surface to the other opposing surface.
The pores were fully formed, and no sintering residue remained in these pores.

Example 2 Naphthalene was pulverized and fed to an alumina ball mill, and to the alumina ball mill, 100 parts of naphthalene was mixed with 20 parts of benzene, 10 parts of ethanol, 10 parts of terpineol, and 0.0 parts of polymethyl methacrylate (Mw: 80,000). One part was added and kneaded for 48 hours, and the viscosity was increased to 2,600 cps while the solvent was scattered at 40°C to obtain a coating liquid.

Next, an aluminum wire with a length of 50 mm and a diameter of 25 C) 4 m was immersed in the coating solution, pulled up and dried to form a naphthalene coating with a total thickness of 60 μm around the aluminum wire.

Next, in the same manner as in Example 1, a metal buried composite (50 x 3 x 1 mm) containing a coated aluminum wire was obtained.

This metal buried composite was supplied to a heating furnace at 20°C and 0.5°C.
After holding at 5 Torr for 20 hours, 20°C, 0, I
Hold U1■ at Torr for 10 o'clock, then further heat at 20℃ for 10
The naphthalene film was sublimated by holding it in Tart for 5 hours and raising the temperature to 60°C at a heating rate of 10°C/hr.
After raising the humidity to 00℃ and holding it for 2 hours to degrease, it was heated to 50℃.
The temperature was raised to 640° C. at a heating rate of /hr and held for 2 hours to obtain a metal composite sintered body having an aluminum wire built therein.

Next, a pore-formed ceramic sintered body was obtained in the same manner as in Example 1. This pore-forming ceramic sintered body has −
Ten holes with a diameter of 272 to 276 μm communicating from one surface to the other opposing surface were formed, and no sintering residue remained in these holes.

Example 3 PbO-3i02-B20 as glass frit powder
3-CaO system (average particle size 5/J m, yield point 684°C
) was used in the same manner as in Example 1 to a thickness of 50 mm.
A 0 μm ceramic green sheet was produced.

This green sheet was heated at a rate of 25℃/hr to 850℃.
After being held at a temperature of 2 hours, the sintered wire was cooled and the shrinkage rate of the sintered wire was measured and found to be 13.0%.

Next, carbon paste (manufactured by Fujikura Kasei Co., Ltd., trade name;
After adding 20 parts of terpineol to 100 parts of
A coating liquid was obtained by increasing the viscosity to 0 cps.

Next, a copper wire with a length of 50 mm and a diameter of 250 μm was immersed in the coating liquid, pulled out and dried at 120°C. The above operation was repeated once more to form a carbon film with a total thickness of 70 μm around the copper wire.

The above green sheet was cut into 50 x 50 mm pieces, four of them were stacked, and then two carbon-coated copper wires were added.
10 green sheets were arranged at tnm intervals, and 4 more green sheets were stacked on top of them, and this was held at 160°C for 2 hours and heated to 30°C.
After crimping with a pressure of 0 kg/cm2, the wire was cut perpendicularly to the copper wire to create a buried metal composite with a built-in coated copper wire (
50X 3
The temperature was raised to 2 o'clock (Holded and degreased. Further 50'
The temperature was raised to 850° C. at a rate of C/hr and held for 2 hours to obtain a metal composite sintered body having a built-in copper wire.

Next, after cooling this metal composite sintered body, sulfuric acid 200
ml, 140 ml of nitric acid, and 660 n+1 of distilled water, heated to 50°C, subjected to ultrasonic vibration for 10 minutes every hour, and held for ]0 hours to elute the copper wire. A pore-forming ceramic sintered body was obtained.

In the obtained pore-formed ceramic sintered body, pores with a diameter of 276 to 280 μm were formed that communicated from one surface to the other opposing surface, and no sintering residue remained in these pores. .

(Effects of the Invention) In the method for producing a pore-forming ceramic sintered body of the present invention, the decomposition and vaporization of the coating material occur before the start of thermal decomposition of the organic binder in the ceramic gellin molded body or after the end of the thermal decomposition, resulting in void formation. is formed, the walls of the ceramic material around the voids do not collapse, and as a result, it is possible to obtain a void-formed ceramic sintered body in which no sintering residue of the ceramic material remains within the voids, and the desired By using a metal material that can be processed into any shape and size as the core material for forming pores, there is a remarkable advantage that pores of any shape and size can be formed in the ceramic sintered body.

[Brief explanation of the drawing]

The drawings illustrate an example of the present invention in the order of its steps, and FIG. 1 is a cross-sectional view of a metal-embedded composite in which a metal material is embedded in a ceramic green molded body, and FIG. 2 is a cross-sectional view of the metal-embedded composite described above. Cross-sectional view showing the state after degreasing the body, 3rd
The figure is a cross-sectional view of the metal composite sintered body obtained by firing.
The figure shows a cross-sectional view of a pore-forming ceramic sintered body obtained by eluting a metal material. 1- Metal material, 2- Coating material, 3 Ceramics green molding 4- Ceramics degreasing 4 pieces
5-. Void, 7- Ceramic sintering r ---- Diameter of metal material, d,, d2 Void, Void coating thickness.

Claims (1)

[Scope of Claims] 1. An organic material that thermally decomposes at a lower temperature than the thermal decomposition starting temperature of the organic binder in a ceramic green molded body consisting of a ceramic material and an organic binder, and a thermal decomposition starting temperature of the organic binder. One or more coating materials selected from the group consisting of a sublimable material that sublimes at a lower temperature and a vaporizable material that decomposes at a higher temperature than the thermal decomposition temperature of the organic binder have a sintering shrinkage dimension equal to or higher than the sintering shrinkage dimension of the ceramic green molded body. a step of forming a metal buried composite by burying a metal material coated with a thickness of , a step of forming a metal composite sintered body by firing the metal buried composite; A method for producing a pore-forming ceramic sintered body, comprising the steps of eluting only a metal material from the body.