JPH0559078B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a ceramic-polysilazane bonded molded product and a bonded ceramic molded product, and more specifically, the present invention relates to a ceramic-polysilazane bonded molded product and a bonded ceramic molded product. The present invention relates to a novel bonded ceramic molded body of oxide and non-oxide materials obtained by bonding and sintering in the presence of a solvent.

[Prior art]

Generally, obtaining ceramic molded products requires the following steps: powder treatment, molding, degreasing, firing, and processing.The parts are first manufactured by cutting a sintered body, and then screwed, bonded, etc. By this method, complex-shaped joined products were obtained, and by methods such as bowling, hollow bodies were obtained. However, there were some shapes that could not be obtained using these methods. In addition, molded products made by these methods have a very large decrease in strength at the joints, so they have had to be used without taking advantage of the inherent characteristics of ceramics.

Furthermore, manufacturing only simple-shaped products such as rods and plates was cited as one of the reasons for inhibiting the development of the ceramics industry. Furthermore, when it is possible to obtain ceramics with complicated shapes or hollow ceramics, the products become extremely expensive and lose their industrial and industrial value.

[Problem to be solved by the invention]

The problem to be solved by the present invention is to solve the difficulties in conventional ceramic molded products and their production, and to provide a new method for manufacturing ceramic molded products having complex shapes and hollow bodies by taking advantage of the inherent characteristics of ceramics. That's true.

[Means and actions for solving the problem]

The present invention involves manufacturing a ceramic-polysilazane bonded molded product by bonding two or more molded products made of a composition containing powdered or fibrous ceramics and polysilazane in the presence of a solvent for the polysilazane; Such a molded body is fired to form a ceramic molded body (herein, this ceramic molded body is referred to as a "bonded ceramic molded body").
That's what it means. ).

The ceramic material in the composition includes:
Si ₃ N ₄ , SiC, A ₂ O ₃ , SiO ₂ , B ₂ O ₃ , B ₄ C,
BN, A ₄ C ₃ , AN, TiO ₂ , TiC, TiN,
Examples include ZrO ₂ , ZrC, and graphite.

The polysilazane has the formula (A) has a repeating unit of formula (B) (Here, R is each independently hydrogen, carbon number 1
-6 alkyl group, alkoxy group having 1 to 6 carbon atoms, substituted or unsubstituted vinyl group, substituted or unsubstituted allyl group, aryl group having 6 to 10 carbon atoms, alkyl group having 1 carbon atom ~6 tri- or di-alkylsilyl groups or dialkylamino groups having 1 to 6 carbon atoms, and n represents an integer greater than 1. ) It consists of a plurality of precursor residues connected to each other by Si ₂ N ₂ bridges.

The polysilazane is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-226890.
It can be produced by the method described in the publication. In this method, anhydrous ammonia is reacted with RSiHX ₂ in solution to produce a cyclic or linear precursor, which has the ability to deprotonate hydrogen from the nitrogen atom adjacent to the silicon atom. An organic silazane polymer is produced by reacting in the presence of a basic catalyst to form a Si ₂ N ₂ bridge.
For example, methyldichlorosilane is cooled in diethyl ether and ammonia gas is blown into it to cause ammonolysis, the resulting ammonium chloride precipitate is filtered out, and the ether is distilled off from the liquid under reduced pressure to obtain the formula (C): We obtain a precursor represented by a repeating skeletal structure.
Since this compound has a number average molecular weight of about 300, it is considered to be a cyclic compound with approximately five repeating skeleton structures on average. When this precursor is dropped into a tetrahydrofuran solution in which potassium hydride (KH) is suspended and stirred, polymerization occurs while generating hydrogen gas. According to the inventor, Seyferth et al. The reaction first generates an amide functional group, and then pairs of such functional groups combine to form a four-membered Si ₂ N ₂ ring to regenerate the metal hydride.

After this reaction is completed, methyl iodide ( _CH3
When I) is added to the reaction system, the amide functional group reacts with methyl iodide to precipitate potassium iodide, The potassium iodide is removed by centrifugation and the solvent is distilled off to obtain a white powdery polymer.
Based on the results of proton type NMR and elemental analysis, this polymer has approximately (CH ₃ SiHNH) _0.39 (CH ₃ SiHNCH ₃ ) _0.04 (CH ₃
It was found to have a composition of SiN) _0.57 (G). This means that it can be roughly expressed by the following model.

The number inside is the precursor residue unit.

Therefore, in this process, when a precursor is polymerized using a metal hydride as a catalyst, the crosslinking reaction may proceed excessively, and the resulting polymer may become insolubilized and gelled into a jelly-like state. This method not only makes it difficult to control the molecular weight and has poor reproducibility, but also the resulting polymer is unstable.
Crosslinking progresses over time and the product becomes insolubilized, resulting in poor storage stability.Furthermore, if the polymerization reaction is carried out at, for example, the reflux temperature of tetrahydrofuran (66°C), it will turn into a gel in a very short time, so it must be carefully carried out at low temperatures (below 30°C). There are problems such as a long time required to obtain a desired molecular weight.

The above-mentioned problems arise in this technique because there are too many cross-linking reaction sites in the precursor. Therefore, by reducing the number of crosslinking reaction sites in the precursor, the above-mentioned problems can be overcome. As a method, firstly, the reaction point in the precursor is (The meaning of R ¹ shown here will be explained later.) A part of is expressed as below () (The meanings of R ² , R ³ and R ⁴ shown here will be explained later.) By reacting with the silazane represented by the following formula () There is a method to inactivate it by changing it to the structure shown in .

Second, when producing the precursor, in addition to R ¹ HSiX ₂ (where X is a halogen atom), R ⁵ R ⁶
There is a method of using a mixture of SiX ₂ (the meanings of R ⁵ and R ⁶ shown here will be described later).

A third method is to use the first and second methods together. Therefore, the preferred polysilazane used in the present invention is at least one of the following polysilazane (a), (b) and (c).

The polysilazane is expressed by the following formula () It has a skeletal structure consisting of repeating units represented by the following formula () A plurality of precursors consisting of repeating units represented by are partially expressed by the following formula () Along with the silazane represented by the following formula () Forms a structural unit represented by the following formula (), and also partially between the precursors: It is constructed by forming structural units shown in and connecting them to each other.

(Here, R ¹ , R ² and R ³ are hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group) group, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a tri- or di-alkylsilyl group having an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
represents a dialkylamino group, R ⁴ is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group, or a C 6 alkyl group. ~10 substituted or unsubstituted aryl groups or alkyl groups representing tri- or di-alkylsilyl groups having 1 to 6 carbon atoms, even if R ¹ , R ² , R ³ and R ⁴ are the same as each other; They can be different. ) The polysilazane has the following formula () It has a skeletal structure consisting of repeating units represented by the following formulas () and (). Multiple precursors consisting of repeating units represented by are mutually expressed by the following formula () It is constructed by forming structural units shown in and connecting them to each other.

(Here, R ¹ represents the same meaning as above, R ⁵
and R ⁶ is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group,
Represents a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a tri- or dialkylsilyl group having an alkyl group having 1 to 6 carbon atoms, and a dialkylamino group having an alkyl group having 1 to 6 carbon atoms. , R ¹ , R ⁵ and R ⁶ may be the same or different. ) The polysilazane is expressed by the following formula () It has a skeletal structure consisting of repeating units represented by the following formulas () and (). A plurality of precursors consisting of repeating units represented by are partially expressed by the following formula () Along with the silazane represented by the following formula () and also partially between the precursors, the following formula () It is constructed by forming structural units shown in and connecting them to each other.

(Here, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ have the same meanings as above and may be the same or different.) It is preferable to include a sintering aid in addition to the ceramic or fibrous ceramic and the polysilazane. As the sintering aid, known materials such as Y ₂ O ₃ , A ₂ O ₃ , magnesia, AN, CaO, La ₂ O ₃ and the like can be used.

To make a molded body from the composition, powder molding,
It is possible to perform CIP treatment after compaction or by injection molding. At this time, in order to bring the composition into a fluid or plasticized state, the composition may contain a solvent for polysilazane, or the composition may be heated to melt the polysilazane.

In order to join the initial molded bodies obtained in this way in the presence of a polysilazane solvent, each surface of the initial molded body to be joined is coated or sprayed with a solvent, or each surface is immersed in a solvent, and then Just attach them to each other before the sides are dry.

The solvent used in the present invention may be any solvent that dissolves polysilazane, which is a ceramic precursor, such as gasoline, kerosene, petroleum ether, light oil, heavy oil, n-decane, 2-methylbutane, 2-methylpentane, dodecane, hexane,
Heptane, pentane, nonane, trimethylhexane, dodecene, heptene, hexene, 1-nonene, aviation lubricant, machine oil, turbine oil, n-tridecane, isooctane, n-octane, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, Acetylacetone, ethyl acetoacetate, methyl acetoacetate, acetonitrile, acetone, methanol, ethanol, allyl alcohol, isoamyl alcohol, isopropyl alcohol, isopropyl ether, isobutyric acid, diethyl ether, 2-ethylhexanol, ethylene glycol, diethylene glycol, ethyl acetate, acetic acid Isopropyl, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, butyraldehyde, isobutanol, tetrahydrofuran, methylfuran, tetrahydropyran, 1,2-dibutoxyethane,
Acetal, pentanone, hexanone, diisobutylketone, propylene carbonate, nitroethane, toluene, benzene, pyridine, ethylenediamine, xylene, nitrobenzene, trichlorobenzene, cyclohexane, cyclohexene, aniline, kyumene, cymene, butylbenzene, mesitylene, tetralin, cyclohexylbenzene, diethylbenzene , pentylbenzene, dibentylbenzene, dodecylbenzene, styrene, methylcyclohexane, ethylcyclohexane, menthane, decalin, pinene, benzyl chloride, ethylbenzene, ethylcyclohexane, dichloromethane, hexachloroethane, isopropyl chloride, propyl chloride, dichloropropane, trichloropropane , allyl chloride, butyl chloride, chloropentane, trichlorobenzene, trichloroethylene,
Perchlorethylene, dichloroethane, tetrachloroethane, pentachloroethane, dichlorobenzene, dichloroethylene, trichloroethylene,
These include propyl bromide, tetrachloroethylene, chlorobenzene, and chloroform.

The bonding equipment used in the present invention may or may not be used as long as it can hold the solvent at the bonded portion until it dries.

By sintering the ceramic-polysilazane bonded body formed in this manner, a bonded ceramic body having a complex shape or a hollow body can be easily obtained. That is, a ceramic molded body having a complicated shape is divided into simple shaped ceramic polysilazane composition molded bodies and molded in advance, and these molded bodies are joined in the presence of a solvent.
Thereafter, by sintering, a bonded ceramic molded body having a complicated shape can be easily obtained. Since this bonded ceramic molded body can easily have, for example, a meandering hollow line inside, it becomes possible to use ceramics for members that could not be manufactured in the past.

〔Example〕

Next, the present invention will be explained based on Examples, but these are just some examples, and the present invention is not limited to these in any way.

Example 1 A mixture of 81.4% by weight of Si ₃ N ₄ powder (SN9S manufactured by Denki Kagaku), 18.2% by weight of polysilazane (type (a) above; molecular weight 800) which is a ceramic precursor, and 0.4% by weight of paraffin wax was kneaded. Melt and knead the compound to obtain a compound, and use the injection molding method to form 5mm x 5
Two columnar bodies measuring mm x 50 mm were molded. One end of each of the two molded bodies was immersed in acetone, immediately pulled up, and the end surfaces were immediately bonded together, and the solvent was dried to obtain a ceramic polysilazane molded body. This was heated to 700°C at a rate of 3°C/mm, then further raised to 1100°C at a rate of 15°C/mm, and then sintered under a pressure of 9.5 kg/cm ² in nitrogen gas at 1850°C to form a bonded ceramic molded body. I got it. The bending strength of this molded body was 20.7 Kg/mm ² compared to bonded ceramics.

Example 2 Si ₃ N ₄ powder (SN9S made by Denki Kagaku) 71.4% by weight, sintering aid Y ₂ O ₃ (Mitsubishi Chemical Itriya 0.8 μm)
5.0% by weight, A ₂ O ₃ (Iwatani Chemical Alumina Type B) 5.0% by weight, polysilazane which is a ceramics precursor (type (a) above; molecular weight 1100) 18.2
A mixture of 0.4% by weight and 0.4% by weight of paraffin wax was melt-kneaded in a kneader to obtain a compound.
Two 5 mm x 5 mm x 50 mm columnar bodies were molded by injection molding, and ceramic polysilazane molded bodies were obtained in the same manner as in Example 1 using toluene.
This was heated to 700℃ at a rate of 3℃/mm, and then further heated to 15℃/mm.
9.5 mm in nitrogen gas at 1850°C after heating to 1100°C
A bonded ceramic molded body was obtained by sintering under pressure of Kg/cm ² . The bending strength of this molded body was 47.3 Kg/mm ² .

Example 3 A mixture of 81.4% by weight of SiC powder (A-2 manufactured by Showa Denko), 18.2% by weight of polysilazane (type (b) above; molecular weight 1300), which is a ceramic precursor, and 0.4% by weight of paraffin wax was put into a kneader. Melt and knead to obtain a compound, and use the injection molding method to form 5mm x 5
A columnar body of mm x 50 mm was molded, and a ceramic polysilazane molded body was obtained using heptane in the same manner as in Example 1. This was heated to 700 °C at a rate of 3 °C/mm, and further heated to 15 °C/mm. After raising the temperature to 1100℃,
A bonded ceramic molded body was obtained by sintering under a pressure of 9.5 kg/cm ² in argon gas at 1700°C. The bending strength of this molded body was 18.3 Kg/mm ² .

[Example 4] A mixture of 76.4% by weight of alumina powder, 5.0% by weight of magnesia, 18.2% by weight of polysilazane (type (c) above; molecular weight 950), which is a ceramic precursor, and 0.4% by weight of paraffin wax was mixed in a kneader. A compound is obtained by melt-kneading, and then molded using injection molding method.
A columnar body of mm x 5 mm x 50 mm was molded, and a ceramic polysilazane molded body was obtained in the same manner as in Example 1 using a heptane solvent.
The temperature was raised to 700°C at a rate of 15°C/mm, and the temperature was further raised to 1100°C at a rate of 15°C/mm, followed by sintering under a pressure of 9.5 kg/cm ² in nitrogen gas at 1700°C to obtain a bonded ceramic molded body. The bending strength of this molded body was 15.3 Kg/mm ² .

〔Effect of the invention〕

As explained above, the bonded ceramic molded body according to the present invention can easily realize the complicated shape of ceramics and can easily realize a ceramic molded body having a winding hollow line inside. It is expected that this will greatly develop the industry.

Claims (1)

[Claims] 1. A ceramic-polysilazane bonded molded product characterized in that two or more molded products made of a composition containing powdered or fibrous ceramics and polysilazane are joined in the presence of a solvent for the polysilazane. Production method. 2. The method according to claim 1, wherein the ceramic in the composition is at least one of silicon nitride, silicon carbide, and alumina. 3. The method according to claim 1 or 2, wherein the polysilazane is at least one of the following polysilazane (a), (b), and (c). The polysilazane (a) is represented by the following formula () It has a skeletal structure consisting of repeating units represented by the following formula () A plurality of precursors consisting of repeating units represented by are partially expressed by the following formula () Along with the silazane represented by the following formula () Forms a structural unit represented by the following formula (), and also partially between the precursors: It is constructed by forming structural units shown in and connecting them to each other. (Here, R ¹ , R ² and R ³ are hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group) group, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, a tri- or di-alkylsilyl group having an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
represents a dialkylamino group, R ⁴ is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group, or a C 6 alkyl group. ~10 substituted or unsubstituted aryl groups or alkyl groups each representing a tri- or di-alkylsilyl group having 1 to 6 carbon atoms, and R ¹ , R ² , R ³ and R ⁴ are the same, and may also be different. ) The polysilazane (b) is represented by the following formula () It has a skeletal structure consisting of repeating units represented by the following formulas () and (). Multiple precursors consisting of repeating units represented by are mutually expressed by the following formula () It is constructed by forming structural units shown in and connecting them to each other. (Here, R ¹ represents the same meaning as above, R ⁵
and R ⁶ is an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted vinyl group, a substituted or unsubstituted allyl group, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a carbon atom of an alkyl group. number is 1
-6 tri- or di-alkylsilyl group, a dialkylamino group in which the alkyl group has 1 to 6 carbon atoms, and R ¹ , R ⁵ and R ⁶ may be the same or different. ) The polysilazane (c) is represented by the following formula () It has a skeletal structure consisting of repeating units represented by the following formulas () and (). A plurality of precursors consisting of repeating units represented by are partially expressed by the following formula () Along with the silazane represented by the following formula () and also partially between the precursors, the following formula () It is constructed by forming structural units shown in and connecting them to each other. (Here, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ have the same meaning as above and may be the same or different.) 4 Claims 1 and 2 or 3. A method for producing a bonded ceramic molded body, which comprises firing the molded body produced by the method described in 3 at a temperature of 800 to 2200°C. 5. The method of claim 1, wherein the composition further comprises a sintering aid. 6. The method according to claim 5, wherein the ceramic in the composition is at least one of silicon nitride, silicon carbide, and alumina. 7. In the method according to claim 5 or 6, the polysilazane is the polysilazane according to claim 3.
The method described above, characterized in that it is at least one of (a), (b), and (c). 8. A method for producing a bonded ceramic molded body, which comprises firing the molded body produced by the method according to claim 5, 6 or 7 at a temperature of 950 to 1900°C.