JP2672106B2 - Silicon nitride inorganic fiber and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a silicon nitride inorganic fiber and a method for producing the same, and more specifically, it relates to Si-M-N-O obtained by spinning / firing polymetallosilazane. System and Si-M-N-H-O-C
System fiber and its manufacturing method. This Si-M-N-H-O
-C-based fibers are useful as a reinforcing material for heat-resistant and high-strength composite materials, and are expected to be widely used in the fields of chemicals / metals, aviation / space, machinery / precision, and automobiles.

[Conventional technology]

It is reported that Si-Ti-C-O fibers consisting essentially of amorphous can be obtained by spinning / firing polytitanocarbosilane obtained by the copolymerization reaction of polycarbosilane and polytitanosiloxane. (Japanese Patent Publication No. 62-5201).

Regarding polysilazane, perhydropolysilazane (JP-A-60-145903, D. Seyferth et al. “A Liquid Silaz
ane Precursor To Silicon Nitride ", Cominications of
Ame. Ceram. Soc., January 1983) and various polyorganosilazanes (JP-A-61-289230).
Si-M-N-O system or Si-M-N-C-O obtained by spinning / calcining polymetallosilazane obtained by condensation of metal alkoxide and polysilazane as a precursor
No conventional H-fiber has been known.

[Problems to be solved by the invention]

Si-Ti-CO fibers or Si-obtained by using the above-mentioned polytitanocarbosilane or polycarbosilane as a precursor
C fiber contains a large amount of free carbon. This is disadvantageous in that sufficient reactivity cannot be obtained when producing a composite material with a metal because it has a high reactivity with a molten metal such as aluminum and causes a decrease in strength.

Therefore, it is considered that the above-mentioned problems can be solved by providing an inorganic fiber based on Si ₃ N ₄ instead of based on SiC, which is conventionally known.
According to the manufacturing method of the Si ₃ N ₄ type inorganic fiber, there are drawbacks such as continuous fiber cannot be manufactured, a large amount of free carbon remains, mechanical strength is low, etc. Is desired to be improved.

Therefore, the present invention has excellent mechanical strength and is particularly suitable for producing a composite material with a metal material.
It aims at providing -N-M-C-O-H type | system | group inorganic fiber.

[Means for achieving the task]

According to the present invention, in order to achieve the above object, silicon,
Nitrogen, oxygen and metals (one or more metal elements selected from the group of metal elements of Groups 1 to 8 of the Periodic Table of Elements) are essential components, and carbon and hydrogen are optional components. The ratio of elements is expressed by atomic ratio, N / Si = 0.3 to 3, O / Si =
0.001 to 15, M / Si (wherein M represents the above metals) =
0.001 to 5, C / Si = 7 or less, H / Si = 15 or less, and having a structure of amorphous to amorphous layer / crystalline layer mixed layer crystal layer, a silicon nitride inorganic fiber I will provide a.

Similarly, according to the present invention, substantially silicon, nitrogen, oxygen, and metals (one or more metal elements selected from the group of metal elements of Groups 1 to 8 of the Periodic Table of Elements). , And carbon and hydrogen, and the ratio of each element is expressed by atomic ratio, N / Si
= 0.3-5, O / Si = 0.001-15, M / Si = 0.3-5, M / Si
(In the formula, M represents the above metals) = 0.001 to 5, C / Si
= 0.001 to 7, H / Si = 0.001 to 15 and a silicon nitride inorganic fiber characterized by having a structure of amorphous to amorphous layer / crystalline layer mixed layer crystal layer.

These silicon nitride-based inorganic fibers are polymetallosilazanes (Japanese Patent Application Nos. 62-223790 and 61-61) which are separately disclosed by the present inventors.
No. -22670, and the patent applications “polymetallosilazane and its production method” filed on the same date as this application) are spun and fired. Regarding the polymetallosilazane and the method for producing the polymetallosilazane, refer to the specifications of each of the above-mentioned patent applications, and the main points thereof are extracted as follows.

This metallosilazane is mainly represented by the general formula (I): (R ¹ , R ² and R ³ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a group other than these groups in which a group directly bonded to silicon is carbon, an alkylsilyl group, Represents an alkylamino group or an alkoxy group, provided that at least one of R ¹ , R ² and R ³ is a hydrogen atom) and has a main skeleton composed of units represented by Polysilazane and the general formula (II): M (OR ⁴ ) _n (II) (wherein, M is an element from Group 1 to Group 8 of the long-term table of the elements; R ⁴ is the same or different. May represent a hydrogen atom, an alkyl group or an aryl group having 1 to 20 carbon atoms, and at least one R ⁴ is the above alkyl group or aryl group; and n is a valence of M.) Obtained by reacting a metal alkoxide represented by It is a polymetallosilazane having a metal / silicon atomic ratio of 0.001 to 3 and a number average molecular weight of about 200 to 500,000, preferably 500 to 50,000.

This polymetallosilazane is prepared by reacting a hydrogen atom bonded to at least a part of silicon atoms and / or a hydrogen atom bonded to a nitrogen atom in the main skeleton of the polysilazane with a metal alkoxide to form a silicon atom and / or a nitrogen atom. Is a compound having a side chain group condensed with a metal alkoxide, or a cyclic or crosslinked structure.

In the reaction between the Si—H bond of polysilazane and the metal alkoxide, the organic group (R ⁴ ) of the metal alkoxide (M (OR ⁴ ) _n ) abstracts the hydrogen atom of the Si—H bond to generate R ⁴ H, thereby desorbing. Upon separation, a Si-OM bond is formed.

On the other hand, in the reaction between the N—H bond of polysilazane and the metal alkoxide, the hydrogen atom of the N—H bond is extracted by the metal alkoxide, and the N—O—M bond or the N—M bond (hereinafter, referred to as these Is represented as an N-Y-M bond).

The metal alkoxide can be at most n-functional, so depending on the type of starting metal alkoxide or the reaction conditions, the resulting polymetallosilazane can be a 1-n functional polymer with respect to the metal. The monofunctional polymer has the following structure in which a pendant group is introduced into Si and / or N of the main chain of polysilazane.

In the 2-n functional polymer, a cyclic or crosslinked structure is formed in the polysilazane skeleton via an M atom. The cyclic structure includes a structure in which two functional groups in one molecule of a metal alkoxide are condensed with adjacent silicon atoms and nitrogen atoms of polysilazane. A crosslinked structure is formed when two or more functional groups of a metal alkoxide are condensed with two or more molecules of polysilazane.

Some 3- to n-functional polymers have both the above-mentioned cyclic structure and cross-linked structure. Usually, the polymer represented by (III) or (IV) is obtained by the reaction between polysilazane and metal alkoxide.

As described above, the structural change from polysilazane to polymetallosilazane is that a pendant group or a cyclic or crosslinked structure is newly formed based on the skeleton of polysilazane.

There is no particular restriction on the molecular weight of the polysilazane to be used, and any available polysilazane can be used, but R ¹ , R ² and R ³ in the formula (I) can be used in view of reactivity with a metal alkoxide.
Is preferably a group having a small steric hindrance. That is, R ¹ , R ² and R ³
Is preferably a hydrogen atom _or a C _1-5 alkyl group, and more preferably a hydrogen atom _or a C _1-2 alkyl group.

But, in view of reactivity, R ⁴ is preferably an alkyl group of C _{1 to 20} in the formula (I), more preferably an alkyl group of C _{1 ~ 10} no particular restrictions on the metal alkoxide used, C
Most preferred are _1-4 alkyl groups. The type of metal of the metal alkoxide is not particularly limited, as long as it is a metal capable of producing a metal alkoxide, and the first to eighth elements of the periodic table of the elements are used.
Most metals in the group form metal alkoxides. Preferred metals are metal elements of Groups 2A and 3 to 5 of the Periodic Table of the Elements, more preferably titanium, aluminum, zirconium, boron and yttrium. Most of these metal alkoxides are on the market, and those not on the market can be produced by the same method as described above.

The mixing ratio of polysilazane and metal alkoxide is M /
Si atomic ratio of 0.001 to 60, preferably 0.01
To 5 and more preferably from 0.05 to 2.5. If the addition amount of metal alkoxide is increased beyond this, without increasing the reactivity with polysilazane,
The metal alkoxide is simply recovered in an unreacted state, and when the amount is small, a remarkable increase in molecular weight does not occur.

The reaction can be carried out without a solvent, but it is more difficult to control the reaction than when an organic solvent is used, and a gel-like substance may be formed. Therefore, it is generally preferable to use an organic solvent.

As the reaction solvent, those not showing reactivity with polysilazane and metal alkoxide are used. Such non-reactive solvents include hydrocarbons, halogenated hydrocarbons,
Ethers, sulfur compounds and the like are used.

The reaction temperature and pressure are not particularly limited, but the reaction temperature is preferably the boiling point of the reaction solvent or metal alkoxide or lower.

The resulting novel polymetallosilazane has a part of the silicon-hydrogen bond of polysilazane condensed with the organic group of the metal alkoxide to form a new silicon-oxygen-metal bond,
And / or a part of the nitrogen-hydrogen bonds of polysilazane is a polymer having a structure condensed with a metal alkoxide. This number average molecular weight is 200,000 to 500,000 and is soluble in organic solvents.

 Next, the spinning process of polymetallosilazane will be described.

The polymetallosilazane solution obtained in the above step is concentrated with a rotary evaporator or the like, or once the solvent is removed and the polymetallosilazane is dried to dryness and a predetermined amount of the polymetallosilazane is dissolved in the solvent to obtain a highly viscous polymetallosilazane. The spinning solution is used as a solution.

The spinning solution containing polysilazane itself exhibits sufficient spinnability suitable for dry spinning without addition of an organic polymer. However, in the present invention, the addition of the organic polymer is not necessarily excluded, and in some cases, a small amount of the organic favor molecule may be added. The concentration of polymetallosilazane in the spinning solution may be such that the spinning solution shows spinnability, the average molecular weight of polymetallosilazane as a spinning raw material,
50 to 98 usually, depending on molecular weight distribution and molecular structure
Good results are obtained in the range of%.

As the spinning solvent, those which do not react with polymetallosilazane as described above are used, and as such non-reactive solvent, hydrocarbons, halogenated hydrocarbons, ether sulfur compounds and the like can be used.

Prior to spinning, the spinning solution is subjected to treatments such as defoaming and filtration to remove substances contained in the solution, such as gels and contaminants, which have a harmful effect on spinning. Dry spinning is convenient for spinning, but centrifugal prevention, blow-off spinning and the like can be used. In dry spinning, a continuous polymetallosilazane fiber can be obtained by discharging a spinning solution from a spinneret into a spinning cylinder to form a fiber, and winding the fiber. In this case, the hole diameter of the spinneret, the discharge speed and the winding speed are generally spinneret hole diameter (diameter): 0.035 to 0.5 mm, preferably 0.05 to 0.3 mm, the winding speed: 30 to 5000 m / min, preferably Is 60 to 2500 m / min.
As the atmosphere in the spinning cylinder, at least one gas selected from dry air, ammonia and an inert gas is used, or at least one of water vapor and the non-reactive solvent is allowed to coexist in the atmosphere. Is heated to control the infusibilization of the polymetallosilazane fiber in the spinning cylinder and the solidification by drying.

The temperature of the spinning solution is usually 20 to 300 ° C, preferably 30 to 200.
℃, the ambient temperature in the spinning cylinder is usually 20 ~ 300 ℃,
It is preferably 40 to 250 ° C.

Since the spinning solvent remains in the dry-spun and wound polymetallosilazane fiber, the fiber should be dried and heated using normal air, vacuum conditions, dry air, ammonia, and an inert gas. To remove. The heating temperature is usually in the range of 20 to 500 ° C. In addition, when the fibers are strained during this drying, it is possible to prevent the fibers from twisting and bending due to the fibers being solidified. Tension is usually in the range of ^{1g / mm 2 ~50kg / mm 2} .

The spun polymetallosilazane fiber is then fired to a ceramic. The firing will be described below.

Firing of the polymetallosilazane fiber is preferably carried out under vacuum or in an atmosphere of an inert gas such as nitrogen or argon, or a gas consisting of ammonia, hydrogen or a mixture thereof. The firing temperature is usually 500-1800
℃, preferably 800 ~ 1600 ℃, baking time 5 minutes ~ 1
0 hours. In this firing step, most of the volatile components in the fiber vaporize in the temperature range of 300 to 600 ° C,
The fibers shrink and generally kink or bend, which can be prevented by applying tension to the fibers during firing. In this case, the tension is usually in the range of 1 g / mm ^{2 to} 50 kg / mm ² .

[Si, N, O, M (C, H)]-based or [Si, N, O, M, C, H] -based inorganic fibers are obtained depending on the type of polymetallosilazane fiber and the firing conditions. The composition of the raw material polymer, the firing atmosphere, and the firing temperature are the most effective composition control means. For example
Fibers free of carbon can be obtained by sufficient firing in N ₂ .

In this firing step, by changing the firing temperature, a completely new Si-M-N-O system or Si-M-N system having various structures from an amorphous phase to an amorphous phase / crystalline layer mixed phase crystal phase is obtained.
A -C-O-H type fiber can be obtained.

Thus, the novel silicon nitride inorganic fiber produced by the above steps contains silicon, nitrogen, oxygen and metals as essential components, and contains carbon and hydrogen as optional components, and the atomic ratio of these elements is N / Si. = 0.3-3, O / Si = 0.01-15, M / Si
(M represents metals) = 0.001 to 5, C / Si = 7 or less, H
/ Si = 15 or less and has a structure of amorphous to amorphous layer / crystalline layer mixed layer crystal layer. The atomic ratio of these is preferably N / Si = 0.6 to 1.4, O / Si = 0.001 to 10 or less, M / Si = 0.01 to 2.5, C / Si = 3.5 or less, and H / Si = 5 or less, More preferably N / Si = 1 to 1.3, O / Si = 0.01 to
4, M / Si = 0.01 to 1, C / Si = 3.5 or less, and H / Si = 1 or less. These atomic ratios can be adjusted by the kind and mixing ratio of the starting polysilazane and the metal alkoxide, the composition of the polymetallosilazane product according to the reaction conditions, and the firing conditions of the spun polymetallosilazane fibers.
By selecting these conditions, it is possible to obtain a nitrogen silicon-based inorganic fiber which is substantially free of carbon and hydrogen, which are optional components, but generally, an inorganic fiber containing silicon, nitrogen, oxygen, metals, carbon and hydrogen is used. A fiber is obtained, and the atomic ratio of these elements is N / Si = 0.33-3, O / Si = 0.001-15, M / Si = 0.001-
5, C / Si = 0.001 / 7, H / Si = 0.001 to 15, preferably N / Si
= 1 to 1.3, O / Si = 0.01 to 4, M / Si = 0.01 to 1, C / Si =
0.01-3.5 and H / Si = 0.01-1.

〔The invention's effect〕

The silicon nitride-based inorganic fiber provided by the present invention is an inorganic fiber having high mechanical strength, particularly high-temperature strength, because the generation of crystalline is suppressed up to high temperature and is amorphous. Also has a higher mechanical strength than conventional silicon nitride-based inorganic fibers. In addition, since this silicon nitride-based inorganic fiber is based on silicon nitride, it is possible to obtain an inorganic fiber that is excellent in high-temperature strength (particularly impact resistance) and electrical insulation, and has little free carbon, so that it is possible to strengthen the composite material. It is suitable as a raw material, and particularly has a compatibility with metal materials because the fibers themselves contain metals, and is suitable for use as a composite material with metal materials.

〔Example〕

Reference Example (Production of Raw Material Perhydropolysilazane) A four-necked flask having an internal volume of 10 was equipped with a gas blowing tube, a mechanical stirrer, and a dewar condenser. After the inside of the reactor was replaced with deoxygenated dry air, 4900 ml of degassed dry pyridine was put into a four-necked flask, and this was ice-cooled. Next, 744 g of dichlorosilane was added to produce a white solid adduct (SiH ₂ Cl ₂ · 2C ₅ H ₅ N). The reaction mixture was ice-cooled, and while stirring, 735 g of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube, and then heated to 100 ° C.

After completion of the reaction, the reaction mixture was centrifuged, washed with dry pyridine, and further filtered under a nitrogen atmosphere to obtain a filtrate.
5100 ml were obtained. The solvent was distilled off from 5 ml of the filtrate under reduced pressure to obtain 0.249 g of resinous solid perhydropolysilazane.

The number average molecular weight of the obtained polymer was 980 as measured by GPC.

Obtained perhydropolysilazane pyridine solution 5100
Dry O-xylene was added to ml and distilled under reduced pressure with a rotary evaporator to obtain 5000 ml of a perhydropolysilazane-dry O-xylene solution.

This was used as a raw material for synthesizing polymetallosilazane thereafter.

Example 1. (Production of Si-Al-N-C-O-H fiber) A four-necked flask having an inner volume of 2000 ml was equipped with a condenser, a seam cap, and a magnetic stirrer. After replacing the inside of the reactor with dry argon, 14.7 g (72.
0 mmol), and 1000 ml of a dry O-xylene solution of perhydropolysilazane obtained in Reference Example (concentration of perhydropolysilazane: 58% by weight) was added with stirring using a syringe to obtain a mixed solution consisting of a homogeneous phase. . This solution was refluxed while stirring at 80 ° C. for 2 hours under an argon atmosphere. The reaction solution changed from colorless to pale yellow.

The generated polyaluminosilazane has a number average molecular weight of 175.
0, weight average molecular weight: 14500 (gel permeation chromatography polystyrene standard).

To this dry xylene solution of polyaluminosilazane, 5.0% by weight of polyaluminosilazane (molecular weight 340,000) was added, and the mixture was stirred for 1 hour, and then the solvent was removed by a rotary evaporator.

The vacuum removal was stopped when the solution became sufficiently spinnable. This solution was transferred to a defoaming container of a dry yarn device to prepare a spinning solution. After static defoaming at 60 ° C for about 2 hours, it was discharged from a nozzle with a diameter of 0.1mm at 30 ° C into a spinning cylinder in an air atmosphere of 130 ° C, wound at a speed of 300m / min, and an average fiber diameter of 10
A μm fiber was obtained.

Then, while applying a tension of 500 g / mm ² to this polymetallosilazane fiber, from room temperature to 1350 ° C. under a nitrogen atmosphere
The temperature was raised at 180 ° C./hour to obtain Si—Al—N—C—O—H fiber.

As a result of X-ray diffraction measurement of this fiber, only the diffraction line of the amorphous phase was observed.

 The mechanical strength and composition of this fiber were as follows.

Mechanical strength Tensile strength (kg / mm ² ) Elastic modulus (ton / mm ² ) 210 to 360 (Average 280) 21 to 67 (Average 26) Composition N / Si = 1.03 O / Si = 0.33 C / Si = 0.64 H / Si = 0.57 Al / Si = 0.05 (Si = 48.6 wt%, Al = 2.5, N = 25.1, C = 13.5, O =
9.3, H = 1.0) Example 2. (Production of Si-Ti-N-C-O-H fiber) A four-necked flask having an inner volume of 2000 ml was equipped with a condenser, a seam cap, a thermometer, and a magnetic stirrer. . After purging the inside of the reactor with dry nitrogen, 1000 g of a dry O-xylene solution of perhydropolysilazane obtained in Reference Example (concentration of perhydropolysilazane: 5.8% by weight) was placed in a four-necked flask, and titanium was stirred. Tetraisopropoxide 7.0 g (24.6 mmol) was added to dry xylene 6.
What was dissolved in 5 ml was added using a syringe. The reaction solution changed from colorless to light brown, purple, and black. After completion of the reaction, the solvent was distilled off under reduced pressure to obtain polyhydrotitanosilazane as a dark brown solid. The yield was 84.0% by weight.

The number average molecular weight of the produced polyhydrotitanosilazane was 1
800, weight average molecular weight: 15000 (gel permeation chromatography, polystyrene standard). To this dry xylene solution of polytitanosilazane, polyethylmethacrylate (molecular weight 340,000) was added to the polytitanosilazane at 5.0% by weight.
After the mixture was stirred for 1 hour, the solvent was removed by a rotary evaporator.

The vacuum removal was stopped when the solution became sufficiently spinnable. This solution was transferred to a defoaming vessel of a dry spinning device to obtain a spinning solution. Approximately 2 hours after static degassing at 60 ℃, 30 ℃
With a nozzle with a diameter of 0.1 mm, it was discharged into a spinning cylinder in an air atmosphere of 130 ° C, wound at a speed of 300 m / min, and the average fiber diameter was 1
Fibers of 0 μm were obtained.

Then, while applying a tension of 500 g / mm ² to this polymetallosilazane fiber in the same manner as in Example 1, the temperature was raised from room temperature to 1350 ° C. at 180 ° C./hour in a nitrogen atmosphere and Si—Ti—
N-COH fiber was obtained.

As a result of X-ray diffraction measurement of this fiber, only the diffraction line of amorphous TiN was found.

As a result of a mechanical test, the composition was as shown below and showed excellent properties.

Tensile strength (kg / mm ² ) 220 to 360 (average 290) Elastic modulus (ton / mm ² ) 22 to 70 (average 28) Composition N / Si = 0.95 O / Si = 0.28 C / Si = 0.35 H / Si = 0.46 Ti / Si = 0.02 (Si = 54.5wt%, Ti = 1.8, N = 25.9, C = 8.1, O = 8.
(7, H = 1.9) Further, the polymetallosilazane fiber was heated from room temperature to 1500 ° C. at 180 ° C./hour at 180 ° C./hour without applying tension, and the fiber obtained was measured by X-ray diffraction. As a result, amorphous TiN was obtained. It was found that the formation of crystalline α-type or β-type silicon nitride was suppressed even at high temperatures.

Example 3 (Production of Si-Zr-N-C-O-H fiber) A four-necked flask having an inner volume of 2000 ml was equipped with a condenser, a seam cap, a thermometer, and a magnetic stirrer. After replacing the inside of the reactor with dry nitrogen, a dry O-xylene solution of perhydropolysilazane obtained in Reference Example was placed in a four-necked flask. Perhydropolysilazane concentration: 5.8
%) 1000 g of zirconium isopropoxide and 18.3 gr (0.055 mol) of zirconium isopropoxide are dried and stirred with 100 m of O-xylene.
What was dissolved in 1 was added. This mixed solution was reacted at 130 ° C. under a nitrogen atmosphere. After GPC fractionation of the reaction solution, the molecular weight was measured and the result was Mn = 1850 (gel permeation chromatography, polystyrene standard). The solvent of the dry xylene solution of polyzirconosilazane was removed by a rotary evaporator.

The vacuum removal was stopped when the solution became sufficiently spinnable.

This solution was transferred to a defoaming vessel of a dry spinning device to obtain a spinning solution. Approximately 2 hours at 60 ℃, after degassing, at 60 ℃, caliber 0.1 mm
Was discharged from the nozzle into a spinning cylinder under an air atmosphere at 120 ° C., and was wound at a speed of 500 m / min to obtain a polyzirconosilazane fiber having an average fiber diameter of 8 μm.

Then, while applying a tension of 500 g / mm ^{2 to} the polyzirconosilazane fiber in the same manner as in Example 1, the temperature was raised from room temperature to 1350 ° C. at 180 ° C./hour in a nitrogen atmosphere and Si—Zr—N— was added.
A COH fiber was obtained.

As a result of X-ray diffraction measurement of this fiber, only the diffraction line of the amorphous phase was found.

 The mechanical strength composition of this fiber is as follows.

Tensile strength (kg / mm ² ) 200 to 320 (average 275) Elastic modulus (ton / mm ² ) 22 to 74 (average 29) Composition N / Si = 1.0 O / Si = 0.24 C / Si = 0.44 H / Si = 0.55 Zr / Si = 0.04 (Si = 50.4 wt%, Zr = 7.0, N = 25.2, C = 9.5, O = 6.
9, H = 1.0) Example 4. (Production of Si-Ti-NO fiber) While applying a tension of 500 g / mm ² to the polytitanosilazane fiber obtained by the same method as in Example 2, In an ammonia atmosphere, the temperature was raised from room temperature to 1350 ° C at 180 ° C / hour, and S
An i-Ti-NO-based fiber was obtained.

As a result of X-ray diffraction measurement of this fiber, only the diffraction line of amorphous TiN was found.

 As a result of the mechanical test, the composition was as shown below.

Tensile strength (kg / mm^Two) 200-350 (average 295) Elastic modulus (ton / mm^Two) 23-72 (28 on average) Composition N / Si = 1.22 O / Si = 0.28 Ti / Si = 0.02 (Si = 55.3 wt%, Ti = 1.8, N = 34.0, O = 8.7, C = 0.
1 , H = 0.1 ) Comparative Example 1 (Production of Si-N-O-C Fiber) Pyridine of perhydropolysilazane obtained in Reference Example
1000 ml of the solution was placed in a pressure resistant reactor with an internal volume of 2 and placed in a nitrogen atmosphere.
The reaction is carried out in an air-tight, closed system while stirring at 120 ° C for 3 hours.
Was. During this time, a large amount of gas is generated and the pressure before and after the reaction is 2.0k.
g / cm^TwoRose. After standing to room temperature, release the gas with nitrogen.
Changed. This modified perhydropolysilazane
The average molecular weight was 2500. Add 1000 ml of ethylben to this solution.
When zen was added and the solvent was distilled off under reduced pressure at a temperature of 70 ° C,
A white powder was obtained.

Toluene was gradually added to this white powder to dissolve it. When the solution became sufficiently spinnable, the addition of toluene was stopped. This solution was transferred to the defoaming container of the dry prevention device, degassed by leaving still at 60 ° C. for about 4 hours, and then discharged from a nozzle with a diameter of 0.08 mm at 40 ° C. into a spinning cylinder under an argon atmosphere of 100 ° C., A fiber having an average fiber diameter of 10 μm was wound at a speed of 1000 m / min. Then, the spun fiber was heated at 180 ° C./hour from room temperature to 1350 ° C. in a N ₂ atmosphere while applying a tension of 500 g / mm ² to obtain a Si—N—O—C—H fiber.

As a result of X-ray diffraction measurement of this fiber, diffraction lines of α-type silicon nitride (CuKα2θ = 30.8 °, 34.5 °, 35.2 °, 38.
8 °) was young but observed.

The mechanical strength of this fiber is Si-M-N-C-O of the example.
It was inferior to -H and Si-M-N-O fibers.

Tensile strength (kg / mm ² ) 150 to 230 (average 200) Elastic modulus (ton / mm ² ) 15 to 32 (average 20) Composition N / Si = 0.96 O / Si = 0.07 C / Si = 0.02 H / Si = 0.08 (Si = 65.4 wt%, N = 31.4, O = 2.5, C = 0.5, H = 0.
2)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Isoda 5-11-1 Tohoku, Niiza-city, Saitama Prefecture (72) Inventor Hiroshi Kaya 12-12-5-5 Nobitome, Niiza City, Saitama Prefecture (56) References 61-28018 (JP, A) JP-A 1-229817 (JP, A) JP-A 62-125015 (JP, A)

Claims (4)

(57) [Claims] 1. Silicon, nitrogen, oxygen and metals (one or more metal elements selected from the group of metal elements of Groups 1 to 8 of the Periodic Table of Elements) as essential components, and carbon and Hydrogen is an arbitrary component, and the ratio of each element is expressed by the atomic ratio, N / Si =
0.3-3, O / Si = 0.001-15, M / Si (where M represents the above metals) = 0.001-5, C / Si = 7 or less, H / Si = 15 or less, and non- A silicon nitride inorganic fiber having a structure of crystalline to amorphous layer / crystalline layer mixed layer crystal layer. 2. Substantially silicon, nitrogen, oxygen and metals (1 selected from the group of metal elements of Groups 1 to 8 of the Periodic Table of the Elements).
One or more metal elements), carbon and hydrogen,
The ratio of each element is expressed by atomic ratio, N / Si = 0.3-5, O / Si
= 0.001 to 15, M / Si (wherein M represents the above metals)
= 0.001 to 5, C / Si = 0.001 to 7, H / Si = 0.001 to 15 and has a structure of amorphous to amorphous layer / crystalline layer mixed layer crystal layer Quality inorganic fiber. 3. A method for producing the silicon nitride inorganic fiber according to claim 1, wherein polymetallosilazane is spun and fired. 4. A method for producing a silicon nitride inorganic fiber according to claim 2, wherein polymetallosilazane is spun and fired.