JP3767170B2 - Sintered SiC fiber bonded body and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic composite material that has a high elastic modulus and excellent high-temperature strength and is difficult to break, and a method for producing the same.
[0002]
[Prior art and problems]
In JP-A-7-69747, Si, C, Ti, Zr, and O are used as constituent elements, and Si, Ti, Zr, and O, which exist so as to fill the gaps between the inorganic fibers. An inorganic fiber sintered body is disclosed in which a layer composed of 1 to 200 nm of amorphous and / or crystalline carbon is present as a boundary layer between inorganic fibers and inorganic substances. ing. The inorganic fiber sintered body described in the publication has high fracture energy and excellent mechanical properties, but sometimes exhibits plastic deformation behavior at a high temperature exceeding 1300 ° C. Thereafter, in Japanese Patent Laid-Open No. 9-52776, TiC having a particle diameter of 100 nm or less in an inorganic substance containing Si, Ti or Zr, and O as constituent elements, which exists so as to fill the gaps of the inorganic fibers, is disclosed. By creating a structure in which crystalline fine particles of ZrC are dispersed, a plastic deformation behavior is further suppressed, and a good composite material that does not exhibit plastic deformation even at 1400 ° C. has been proposed in an immediate fracture strength measurement test.
[0003]
However, there is a limit to the suppression of plastic flow by such a particle dispersion structure, and sufficient results have not been obtained with creep resistance in the atmosphere at 1400 ° C., and a slight decrease in strength due to plastic deformation at 1500 ° C. Was also recognized.
By the way, recent progress in aircraft jet engines is remarkable, and accordingly, it is strongly desired to increase the temperature of combustion gases and to reduce the weight of materials used. Therefore, ceramic materials that are resistant to cracking and that can withstand even at ultra-high temperatures exceeding 1400 ° C. are becoming more important.
[0004]
[Means for Solving the Problems]
An object of the present invention is to provide a high heat-resistant sintered SiC fiber bonded body that satisfies the above-mentioned demand and a method for producing the same. According to the present invention, mainly an inorganic fiber composed of a sintered structure of SiC, 2A group, all inorganic fibers containing at least one metal atom selected from the group consisting of Group 3A and 3B group metal atom Alternatively, most of them are deformed into a polygonal shape and filled in a state very close to a close-packed structure, and a boundary layer mainly composed of 1 to 50 nm of carbon is formed between the fibers, and the density is 2. There is provided a sintered SiC fiber bonded body having a strength of 7 g / cm 3 or more, an elastic modulus of 200 GPa or more , and a strength at 1600 ° C. of 80% or more of room temperature strength .
[0005]
Furthermore, according to the present invention, the polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more or a heated reaction product thereof is selected from the group consisting of 2A group, 3A group and 3B group metal elements. The first step of adding a compound containing at least one metal element and reacting by heating in an inert gas to prepare the metal element-containing organosilicon polymer, melt spinning the metal element-containing organosilicon polymer and spinning A second step for obtaining fibers, a third step for adjusting the infusible fibers by infusibilizing the spun fibers in an oxygen-containing atmosphere at 50 to 170 ° C., a fourth step for mineralizing the infusible fibers in an inert gas, inorganic A pre-shaped product is prepared from the engineered fiber, and this is charged into a mold, and in an atmosphere consisting of at least one selected from the group consisting of vacuum, inert gas, reducing gas and hydrocarbon, in a temperature range of 1700 to 2200 ° C. Method for producing a sintered SiC fiber conjugates, comprising the fifth step for pressurizing is provided.
[0006]
Alternatively, at least one metal element selected from the group consisting of 2A group, 3A group, and 3B group metal elements in polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more or a heated reaction product thereof A first step of preparing a metal element-containing organosilicon polymer by adding a compound containing a metal and reacting by heating in an inert gas, a second step of obtaining a spun fiber by melt spinning the metal element-containing organosilicon polymer , A third step of adjusting the infusible fiber by infusibilizing the spun fiber at 50 to 170 ° C. in an oxygen-containing atmosphere, preparing a pre-shaped product from the infusible fiber, charging it into a mold, vacuum, inert gas, It comprises a fourth step of mineralizing in an atmosphere consisting of at least one selected from the group consisting of a reducing gas and a hydrocarbon, further raising the temperature to 1700-2200 ° C. and pressurizing it as it is Method for producing a sintered SiC fiber bonding is provided.
[0007]
First, the sintered SiC fiber bonded body of the present invention will be described.
The fiber material constituting the sintered SiC fiber bonded body of the present invention is mainly composed of a sintered structure of SiC crystals, and exhibits a strong interfacial strength between SiC crystals in a well-sintered region. It proceeds in the crystal grains. In observation of the fracture surface of the fiber material constituting the sintered SiC fiber bonded body of the present invention, such intragranular fracture of SiC is recognized in an area of at least 30% or more of the fiber material cross section.
In addition, in the fracture surface of the above-mentioned fiber material, there may be a case where a good sintered region confirmed by intragranular fracture between SiC crystals and a grain boundary fracture region are mixed, and it contains 10% or less voids. There may be.
[0008]
The fiber material contains at least one metal atom selected from the group consisting of Group 2A, Group 3A and Group 3B metal atoms.
The ratio of the elements constituting the fiber is usually Si: 55 to 70% by weight, C: 30 to 45% by weight, M (2A group, 3A group and 3B group metal elements): 0.05 to 4.0. % By weight, preferably 0.1 to 2.0% by weight.
Among the metal elements of Group 2A, Group 3A and Group 3B, Be, Mg, Y, Ce, B, and Al are particularly preferable, and these are all known as SiC sintering aids, and are organic. There are chelates and alkoxide compounds that can react with Si-H bonds of silicon polymers. If the proportion of this metal is excessively small, sufficient sinterability of the fiber material cannot be obtained, and if the proportion is excessively high, grain boundary fracture increases, leading to a decrease in mechanical properties.
[0009]
All or most of the fiber material constituting the sintered SiC fiber bonded body of the present invention is deformed into a polygonal shape and filled in a state very close to a close-packed structure. In addition, a boundary layer mainly composed of 1 to 50 nm carbon is formed in the boundary region between each fiber, and this acts as a sliding layer at the time of breakage, thereby expressing a large breaking energy, that is, difficulty in cracking.
Reflecting the above-described structure, the sintered SiC fiber bonded body of the present invention exhibits extremely excellent high-temperature mechanical properties that the strength at 1600 ° C. is 80% or more of the room temperature strength.
[0010]
Moreover, the fiber material which comprises the sintered SiC fiber coupling body of this invention is the orientation state similar to the lamination | stacking state of the sheet-like thing put together in one direction, the orientation state similar to the lamination | stacking state of a two-dimensional fabric, 3 It can consist of an orientation state similar to the state of the dimensional fabric, a random orientation state, or a composite structure thereof. These are selected for a while depending on the mechanical characteristics required for the target shape.
[0011]
Next, the manufacturing method of the sintered SiC fiber conjugate of the present invention will be described.
In the present invention, two types of manufacturing methods in which the mineralization method is changed are proposed.
In the first method, polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more or a heated reaction product thereof is selected from at least one selected from the group consisting of 2A group, 3A group, and 3B group metal elements. A first step of adding a compound containing a metal element and reacting by heating in an inert gas to prepare a metal element-containing organosilicon polymer, melt spinning the metal element-containing organosilicon polymer, A second step of obtaining, a third step of adjusting the infusible fiber by heating the spun fiber at 50 to 170 ° C. in an oxygen-containing atmosphere, a fourth step of mineralizing the infusible fiber in an inert gas, from the mineralized fiber A pre-shaped product is prepared, charged in a mold, and pressurized in a temperature range of 1700 to 2200 ° C. in an atmosphere of at least one selected from the group consisting of vacuum, inert gas, reducing gas and hydrocarbon. That consists of the fifth step.
[0012]
First Step In the first step, a metal-containing organosilicon polymer that is a precursor polymer is prepared.
Polysilane is a linear or cyclic polymer obtained by dechlorinating one or more kinds of dichlorosilane using sodium according to the method described in “Chemistry of Organosilicon Compounds” Chemistry (1972), for example. The number average molecular weight is usually 300 to 1000. The polysilane in the present invention can have a hydrogen atom, a lower alkyl group, an aryl group, a phenyl group or a silyl group as a side chain of silicon. In any case, the ratio of carbon atoms to silicon atoms is in molar ratio. It is necessary to be 1.5 or more. If this condition is not satisfied, all of the carbon in the fiber will be desorbed as CO gas in the temperature rising process until sintering, together with the oxygen introduced during infusibilization, and no boundary carbon layer between the fibers will be formed Therefore, it is not preferable.
[0013]
The polysilane in the present invention includes an organosilicon polymer partially containing a carbosilane bond in addition to the polysilane bond unit obtained by heating the above-mentioned chain or cyclic polysilane. Such an organosilicon polymer can be prepared by a method known per se. Examples of the preparation method include a method in which a linear or cyclic polysilane is heated and reacted at a relatively high temperature of 400 to 700 ° C., a phenyl group-containing polyborosiloxane is added to the polysilane, and a relatively low temperature of 250 to 500 ° C. The method of heating reaction can be mentioned. The number average molecular weight of the organosilicon polymer thus obtained is usually 1000 to 5000.
[0014]
The phenyl-containing polyborosiloxane can be prepared according to the method described in JP-A Nos. 53-42300 and 53-50299. For example, phenyl-containing polyborosiloxane can be prepared by a dehydrochlorination condensation reaction between boric acid and one or more diorganochlorosilanes, and the number average molecular weight is usually 500 to 10,000. The addition amount of the phenyl group-containing polyborosiloxane is usually 15 parts by weight or less with respect to 100 parts by weight of the polysilane.
[0015]
By adding a predetermined amount of a compound containing a metal element of 2A group, 3A group and 3B group to polysilane and reacting in an inert gas at a temperature usually in the range of 250 to 350 ° C. for 1 to 10 hours A metal element-containing organosilicon polymer as a raw material can be prepared. The metal element is used in such a ratio that the metal element content in the finally obtained sintered SiC fiber bonded body is 0.05 to 4.0% by weight, and the specific ratio is determined according to the teaching of the present invention. The trader can make an appropriate decision.
The metal element-containing organosilicon polymer is a crosslinked polymer having a structure in which at least a part of silicon atoms of polysilane are bonded with or without metal atoms and oxygen atoms.
[0016]
As the compound containing a metal element of Group 2A, Group 3A, and Group 3B added in the first step, an alkoxide, acetylacetoxide compound, carbonyl compound, cyclopentadienyl compound, or the like of the metal element can be used. Examples include beryllium acetylacetonate, magnesium acetylacetonate, yttrium acetylacetonate, cerium acetylacetonate, butanoic acid borate, and aluminum acetylacetonate.
These all react with the Si-H bond in the organosilicon polymer produced during the reaction with polysilane or its heated reaction product, and each metal element is bonded to Si directly or via other elements. It can be generated.
[0017]
Second Step In the second step, a spun fiber of a metal element-containing organosilicon polymer is obtained.
The metal element-containing organosilicon polymer as a precursor polymer can be spun by a method known per se such as melt spinning and dry spinning to obtain a spun fiber.
[0018]
Third Step In the third step, the infusible fiber is prepared by heating the spun fiber at 50 to 170 ° C. in an oxygen-containing atmosphere.
The purpose of infusibilization is to form a bridging point by oxygen atoms between the polymers constituting the spun fiber so that the infusible fiber does not melt in the subsequent mineralization step and adjacent fibers do not fuse. It is to be.
Examples of the gas constituting the oxygen-containing atmosphere include air, oxygen, and ozone. The infusibilization temperature is 50 to 170 ° C., and the infusibilization time depends on the infusibilization temperature, but is usually from several minutes to 30 hours.
It is desirable to control the oxygen content in the infusible fiber to be 8 to 16% by weight. Most of this oxygen remains in the fiber even after mineralization in the next step, and plays an important role in desorbing excess carbon in the inorganic fiber as CO gas in the temperature rising process until the final sintering. To do.
When the oxygen content is less than 8% by weight, excess carbon in the inorganic fiber remains unnecessarily, segregates and stabilizes around the SiC crystal in the temperature rising process, and inhibits SiC sintering. When the amount is more than 16% by weight, surplus carbon in the inorganic fiber is completely desorbed and a boundary carbon layer between the fibers is not generated. Both of these adversely affect the mechanical properties of the resulting material.
[0019]
The infusible fiber is preferably preheated in an inert atmosphere.
Nitrogen, argon, etc. can be illustrated as gas which comprises inert atmosphere. The heating temperature is usually 150 to 800 ° C., and the heating time is several minutes to 20 hours. By preheating the infusible fiber in an inert atmosphere, while preventing the incorporation of oxygen into the fiber, the cross-linking reaction of the polymer constituting the fiber is further advanced, so that the infusibility from the precursor metal polymer is achieved. While maintaining the excellent elongation of the fiber, the strength can be further improved, whereby the mineralization in the next step can be performed stably with good workability.
[0020]
Fourth Step In the fourth step, the infusible fiber is mineralized by heat treatment at a temperature in the range of 1000 to 1700 ° C. in an inert gas atmosphere such as argon in a continuous or batch manner.
[0021]
Fifth Step In the fifth step, first, after forming the mineralized fibers into a sheet shape, a woven shape, or a chop shape, a preliminary shape made of at least one of them is prepared. Next, the preform is placed in a mold and pressurized in a temperature range of 1700 to 2200 ° C. in an atmosphere of at least one selected from the group consisting of vacuum, inert gas, reducing gas and hydrocarbon.
In the temperature raising process until pressurization in the fifth step, the temperature raising rate is adjusted at a temperature within a certain range or held at a certain temperature for a certain time for the purpose of effectively causing the desorption of CO. May be. At that time, a pressurization program adapted to the CO desorption rate may be incorporated.
[0022]
Next, the second production method is basically the same as the first method, except that the infusibilized fiber is charged into a pressurizing mold and mineralized in the mold.
[0023]
【Example】
In order to explain the present invention in more detail, examples and comparative examples are shown below.
Reference example 1
To anhydrous xylene containing 400 g of sodium, 1 L of dimethyldichlorosilane was dropped while heating and refluxing xylene under a nitrogen gas stream, followed by heating to reflux for 10 hours to form a precipitate. This precipitate was filtered and washed with methanol and then with water to obtain 420 g of white polydimethylsilane.
[0024]
Reference example 2
750 g of diphenyldichlorosilane and 124 g of boric acid were heated at 100 to 120 ° C. in n-butyl ether under a nitrogen gas atmosphere, and the resulting white resinous material was further heated at 400 ° C. in vacuum for 1 hour to contain a phenyl group 530 g of polyborosiloxane was obtained.
[0025]
Example 1
4 parts of the phenyl group-containing polyborosiloxane obtained in Reference Example 2 was added to 100 parts of the polydimethylsilane obtained in Reference Example 1, and heat condensed at 350 ° C. for 5 hours in a nitrogen gas atmosphere. An organosilicon polymer was obtained. Polyaluminocarbosilane was synthesized by adding 7 parts of aluminum-tri- (sec-butoxide) to a xylene solution in which 100 parts of this organosilicon polymer was dissolved, and causing a crosslinking reaction at 310 ° C. under a nitrogen gas stream.
The polyaluminocarbosilane was melt-spun at 245 ° C., heat-treated in air at 140 ° C. for 5 hours, and further heated in nitrogen at 300 ° C. for 10 hours to obtain infusible fibers.
This infusible fiber was continuously fired at 1500 ° C. in nitrogen to synthesize a silicon carbide-based continuous inorganic fiber. The resulting continuous inorganic fiber is formed into a sheet that is aligned in one direction, laminated with the fiber direction aligned, charged into a carbon mold, and then heated to 2000 ° C. while applying a pressure of 50 MPa. Thus, a sintered SiC fiber bonded body was manufactured.
[0026]
The obtained sintered SiC fiber bonded body has a chemical composition of Si: 67 wt%, C: 31 wt%, O: 0.3 wt%, Al: 0.8 wt%, B: 0.06 wt%, and Si by atomic ratio. : C: O: Al = 1: 1.08: 0.008: 0.012, and the fiber material is deformed into a polygonal shape as shown in FIG. A boundary carbon layer of about 10 nm was formed. The sintered SiC fiber bonded body had a density of 2.95 g / cm ³ , a four-point bending strength and an elastic modulus of 550 MPa and 340 GPa, respectively, indicating a fracture mode peculiar to the composite material. The 4-point bending strength at 1600 ° C. was 570 MPa, and no decrease in strength was observed.
[0027]
Example 2
The polydimethylsilane obtained in Reference Example 1 was subjected to thermal condensation at 470 ° C. for 6 hours in a nitrogen gas atmosphere to obtain a high molecular weight organosilicon polymer. Polyaluminocarbosilane was synthesized by adding 7 parts of aluminum-tri- (sec-butoxide) to a xylene solution in which 100 parts of this organosilicon polymer was dissolved, and performing a crosslinking reaction at 320 ° C. under a nitrogen gas stream.
The polyaluminocarbosilane was melt-spun at 255 ° C. and then heat-treated in air at 170 ° C. for 10 hours, and further heated in nitrogen at 320 ° C. for 9 hours to obtain an infusible fiber. This infusibilized fiber was processed into a sheet-like material aligned in one direction, then charged into a carbon mold, heated to 1300 ° C. under reduced pressure, and held for 1 hour. Thereafter, argon gas was introduced, the temperature was raised to 1800 ° C., and then pressurized to 50 MPa to produce a sintered SiC fiber bonded body. The sintered SiC fiber bonded body had a density of 3.05 g / cm ³ , a four-point bending strength and an elastic modulus of 580 MPa and 330 GPa, respectively, indicating a composite fracture mode. The 4-point bending strength at 1600 ° C. was 565 MPa, and the initial 97% strength was maintained.
[0028]
Example 3
Instead of adding 7 parts of aluminum-tri- (sec-butoxide) of Example 1, 4 parts of aluminum-tri- (sec-butoxide) and 3 parts of magnesium acetylacetonate were added, and the mixture was heated at 310 ° C. under a nitrogen gas stream. By carrying out a crosslinking reaction, a modified polycarbosilane having aluminum and magnesium introduced therein was obtained.
The modified carbosilane was melt-prevented at 255 ° C., then heat-treated in air at 150 ° C. for 3 hours, and further heated in nitrogen at 300 ° C. for 9 hours to obtain an infusible fiber. The infusible fiber was continuously fired at 1450 ° C. in argon to synthesize amorphous silicon carbide fiber. The chemical composition of this amorphous silicon carbide fiber is as follows: Si: 53 wt%, C: 33.4 wt%, O: 13 wt%, Al: 0.34 wt%, B: 0.01 wt%, Mg: 0.30 wt% there were.
The obtained amorphous silicon carbide fiber is formed into a sheet-like material aligned in one direction, laminated with the fiber direction aligned, charged into a carbon mold, and then hot-pressed with argon. Then, the temperature was raised to 1600 ° C., and a pressure of 40 MPa was applied to raise the temperature to 1800 ° C. to produce a sintered SiC fiber bonded body.
[0029]
The chemical composition of the obtained sintered SiC fiber bonded body was Si: 67.5 wt%, C: 31 wt%, O: 0.3 wt%, Al: 0.74 wt%, B: 0.06 wt%, Mg: 0 .4 wt%, and the atomic ratio of Si: C: O: Al = 1: 1.07: 0.0078: 0.0114, and each fiber material is deformed into a polygonal shape and is closely packed, An average boundary carbon layer of 15 nm was formed between the fibers. The sintered fiber bonded body had a density of 3.05 g / cm ³ , a four-point bending strength and an elastic modulus of 530 MPa and 295 GPa, respectively, and exhibited a fracture mode peculiar to a composite material. The room temperature strength was maintained even at 1600 ° C.
[0030]
Example 4
Instead of adding 7 parts of aluminum-tri- (sec-butoxide) in Example 1, 4 parts of aluminum-tri- (sec-butoxide) and 4 parts of yttrium acetylacetonate were added, and the mixture was heated at 300 ° C. under a nitrogen gas stream. By carrying out a crosslinking reaction, a modified polycarbosilane having aluminum and yttrium introduced therein was obtained.
This modified carbosilane was prevented from melting at 265 ° C., then heat-treated in air at 150 ° C. for 3 hours, and further heated in nitrogen at 300 ° C. for 10 hours to obtain an infusible fiber. The infusible fiber was continuously fired at 1450 ° C. in argon to synthesize amorphous silicon carbide fiber. The chemical composition of this amorphous silicon carbide fiber is as follows: Si: 52.5 wt%, C: 34.5 wt%, O: 12 wt%, Al: 0.35 wt%, B: 0.005 wt%, Y: 0.56 wt% %Met.
The obtained amorphous silicon carbide fiber is formed into a sheet-like material aligned in one direction, laminated with the fiber direction aligned, charged into a carbon mold, and then hot-pressed with argon. Then, the temperature was raised to 1650 ° C., and a pressure of 50 MPa was applied to raise the temperature to 1900 ° C. to produce a sintered SiC fiber bonded body.
[0031]
The chemical composition of the obtained sintered SiC fiber bonded body was as follows: Si: 67.87 wt%, C: 31 wt%, O: 0.3 wt%, Al: 0.5 wt%, B: 0.03 wt%, Y: 0 3 wt%, and the atomic ratio of Si: C: O: Al = 1: 1.07: 0.0077: 0.0076, and each fiber material is deformed into a polygonal shape and is closely packed, An average boundary carbon layer of 13 nm was formed between the fibers. The sintered fiber bonded body had a density of 2.95 g / cm ³ , a four-point bending strength and an elastic modulus of 570 MPa and 305 GPa, respectively, and exhibited a fracture mode specific to the composite material. The room temperature strength was maintained even at 1600 ° C.
[0032]
Comparative Example 1
20 parts of the phenyl group-containing polyborosiloxane obtained in Reference Example 2 was added to 100 parts of the polydimethylsilane obtained in Reference Example 1, and heat condensed at 350 ° C. for 10 hours in a nitrogen gas atmosphere. Polycarbosilane was obtained. This polycarbosilane was melt-spun at 232 ° C. and then heat-treated in air at 160 ° C. for 9 hours to obtain an infusible fiber. This infusible fiber was continuously fired at 1500 ° C. in nitrogen to synthesize a silicon carbide-based continuous inorganic fiber. Using this continuous inorganic fiber, a fiber bonded body was produced in the same manner as in Example 1. The density of this fiber bonded body was as small as 2.56 g / cm ³ , no intragranular fracture of SiC was observed, and the strength and elastic modulus were as low as 200 MPa and 180 GPa, respectively.
[Brief description of the drawings]
FIG. 1 is an electron micrograph in place of a drawing showing the crystal structure of a sintered SiC fiber bonded body obtained in Example 1. FIG.

Claims (4)

An inorganic fiber mainly composed of a sintered structure of SiC, and all or most of the inorganic fibers containing at least one metal atom selected from the group consisting of 2A, 3A and 3B group metal atoms are polygonal. It is packed in a state very close to a close-packed structure, and a boundary layer mainly composed of 1 to 50 nm carbon is formed between the fibers, and the density is 2.7 g / cm 3 or more, and elasticity A sintered SiC fiber bonded body characterized in that the strength at a rate of 200 GPa or more and 1600 ° C. is 80% or more of the room temperature strength . Orientation state similar to the lamination state of the sheet-shaped material in which the inorganic fibers are aligned in one direction, the alignment state similar to the lamination state of the two-dimensional fabric, the orientation state similar to the state of the three-dimensional fabric, or the random orientation state The sintered SiC fiber bonded body according to claim 1, comprising any one of the above or a composite structure thereof. Contains at least one metal element selected from the group consisting of Group 2A, Group 3A and Group 3B metal elements in a polysilane having a ratio of carbon atoms to silicon atoms of 1.5 or more in molar ratio or a heated reaction product thereof A first step of preparing a metal element-containing organosilicon polymer by adding a compound to be heated and reacting in an inert gas, a second step of obtaining a spun fiber by melt spinning the metal element-containing organosilicon polymer, spinning A third step of adjusting the infusible fiber by heating the fiber at 50 to 170 ° C. in an oxygen-containing atmosphere, a fourth step of mineralizing the infusible fiber in an inert gas, and preparing a preform from the mineralized fiber This is a fifth step in which this is charged into the mold and pressurized in a temperature range of 1700 to 2200 ° C. in an atmosphere of at least one selected from the group consisting of vacuum, inert gas, reducing gas and hydrocarbon. Method for producing a sintered SiC fiber conjugate characterized and. Contains at least one metal element selected from the group consisting of Group 2A, Group 3A and Group 3B metal elements in a polysilane having a ratio of carbon atoms to silicon atoms of 1.5 or more in molar ratio or a heated reaction product thereof A first step of preparing a metal element-containing organosilicon polymer by adding a compound to be heated and reacting in an inert gas, a second step of obtaining a spun fiber by melt spinning the metal element-containing organosilicon polymer, spinning The third step of adjusting the infusible fiber by heating the fiber in an oxygen-containing atmosphere at 50 to 170 ° C., preparing a pre-shaped product from the infusible fiber, charging it in a mold, vacuum, inert gas, reducing gas, and Sintered SiC characterized by comprising a fourth step of mineralizing in an atmosphere of at least one selected from the group consisting of hydrocarbons, and further raising the temperature to 1700-2200 ° C. and pressurizing it as it is維結 manufacturing method of the united.

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