JP2001181046A - Inorganic fiber bound ceramics, method for producing the same and high-surface accuracy member using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a material having high fracture resistance and excellent in surface smoothness and to provide a method for producing the material. SOLUTION: The ceramics comprise inorganic fibers containing (a) an amorphous substance composed of Si, M, C and O, (b) an aggregate of crystalline microparticles of β-SiO2, MC and C and an amorphous substance of SiO2 and MO2 (M denotes Ti or Zr) or (c) a mixture of the amorphous substance (a) with the aggregate (b) and an inorganic substance containing (d) an amorphous substance composed of Si and O, as necessary, M, (e) a crystalline substance composed of crystalline SiO2 and/or MO2 or (f) a mixture of the above amorphous substance (d) with the above crystalline substance (e) and further containing crystalline microparticles composed of MC having <=100 nm particle diameter dispersed therein or the crystalline microparticles composed of the MC having <=100 nm particle diameter and crystalline particles composed of the MC having >100 nm to 1, 000 nm particle diameter dispersed therein and present so as to fill interstices among the inorganic fibers. The content of the inorganic fibers is >=80 vol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic fiber-bound ceramic having extremely high surface smoothness and high puncture resistance and exhibiting excellent mechanical properties even in air at 1300 ° C. or higher, a method for producing the same, and a method for producing the same The present invention relates to a high-precision member using the same. In particular, members having extremely high surface accuracy and requiring high breaking resistance, such as fitting parts, screw parts, sliding parts, which require high product dimensional tolerances,
It can be applied to mechanical seal parts or parts for gas generator engines.

[0002]

2. Description of the Related Art A simple ceramic material represented by silicon carbide, silicon nitride and the like has high heat resistance and hardness, and shows excellent surface smoothness when subjected to surface processing. Accordingly, oil is used as a sliding material for rolling bearings, sliding bearings, and the like in a high-temperature region or an extremely low-temperature region where oil cannot be used as a lubricant. In addition, since these simple ceramics exhibit excellent strength at a high temperature of 1300 ° C. or higher, they have been expected as members for high-efficiency gas turbines. However, it has the weakness inherent in simple ceramics, and has small internal pores,
Alternatively, it is very sensitive to cracks and its properties are significantly reduced. In order to increase reliability, it is necessary to improve brittleness and increase resistance at the time of breaking, that is, to increase breaking energy.

[0003] The carbon fiber reinforced carbon matrix composite material (hereinafter referred to as C / C composite material) and the ceramic fiber reinforced ceramic matrix composite material (hereinafter referred to as CMC) have the above-mentioned brittleness of a single ceramic. It is a material that has been improved without deteriorating high-temperature characteristics, and has been actively studied as an ultra-high-temperature material.

[0004] These composites are prepared by chemical vapor deposition (CV).
D method), chemical osmosis gas phase method (CVI method), polymer impregnation method (PIP
Method) or hot press method. In any of the methods, in particular, a composite material reinforced with continuous fibers tends to have pores remaining therein and has a lower density than a single ceramic. Therefore, there is a portion where the pores are exposed on the surface after machining, and in the periphery thereof, the fiber and the matrix are likely to be missing. In addition, if foreign matter enters the pores exposed on the surface, in the case of a sliding material or the like, the frictional resistance increases. Therefore, in a composite material, it is necessary to improve the smoothness of the surface and eliminate pores exposed on the surface. Ceramic fiber-reinforced glass-ceramic-based composite materials, which are one type of CMC, have relatively high density, but since the matrix material is glass, the strength is reduced due to the softening of the matrix at 1200 ° C. or higher. Therefore, use at a high temperature of 1300 ° C. or more is difficult.

As a means for improving the surface compactness of the C / C composite material or the SiC / SiC composite material, surface coating can be considered, but the additional coating step increases the cost. Further, the coating film is peeled off due to a thermal shock and collision of a foreign substance, or when a substance different from the base material is coated, due to a difference in thermal expansion.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a material having a high breaking resistance and excellent surface smoothness without a surface coating, and a method for producing the same. It can be applied to parts that have surface accuracy and high fracture resistance, such as fitting parts, screw parts, sliding parts, mechanical seal parts, or parts for gas generator engines that require high product dimensional tolerances. .

According to the present invention, (a) an amorphous substance composed of Si, M, C and O, (b) crystalline fine particles of β-SiC, MC and C, and an amorphous substance of SiO ₂ and MO ₂ (M is T
i or Zr), or (c) the amorphous material of (a) and the above
(b) an inorganic fiber containing a mixture with the aggregate of (b), an amorphous material consisting of (d) Si and O, and optionally M, present so as to fill gaps between the inorganic fibers, (e) crystal Quality S
a crystalline substance consisting of SiO ₂ and / or MO ₂ or (f)
(d) an inorganic substance containing a mixture of the amorphous substance and the crystalline substance of (e), and in which crystalline fine particles of MC having a particle diameter of 100 nm or less are dispersed, or a particle having a particle diameter of 100 nm or less. It is composed of an inorganic substance in which crystalline fine particles composed of MC and crystalline particles composed of MC having a particle diameter of more than 100 nm to 1000 nm are dispersed, and the content of the inorganic fiber is 80% by volume or more, and further, the inorganic fiber And the above-mentioned inorganic substance, and 1 to 1000 nm of amorphous and / or crystalline carbon in which crystalline particles composed of MC having a particle size of 1000 nm or less are dispersed as an interface layer between inorganic fibers and the inorganic fibers are inconsistently mixed. Inorganic fiber-bound ceramics with a layer, the surface of the inorganic fiber-bound ceramics has a ten-point average roughness (Rz) of 5 μm or less (reference length 3 mm) or less, and the stress-displacement curve is non-linear in a fracture test. Inorganic fiber characterized by not showing instantaneous destruction A fiber bonded ceramic is provided.

Further, according to the present invention, there is provided an inorganic fiber mainly comprising a crystal structure of SiC, wherein the inorganic fiber comprises a 2A group, a 3A group and a 3B group.
Inorganic fibers containing at least one metal atom selected from the group consisting of group metal atoms are bonded to a structure that is very close to close-packed, and a boundary layer mainly composed of 1 to 50 nm carbon is formed between the fibers. The formed inorganic fiber-bonded ceramics, wherein the surface of the inorganic fiber-bonded ceramics has a ten-point average roughness (Rz) of 5 μm or less (reference length of 3 mm) or less, and the stress-displacement curve is non-linear in a fracture test. And an inorganic fiber-bonded ceramic characterized by not being destroyed immediately.

Further, according to the present invention, there is provided an inorganic fiber comprising an inner surface layer and a surface layer, wherein the inner surface layer comprises (a) Si, M,
Amorphous substance consisting of C and O, (b) β-SiC, MC and C
Crystalline and ultrafine particles aggregate of an amorphous substance of SiO ₂ and MO ₂ of the (M represents Ti or Zr.), Or (c) the amorphous substance and the above-mentioned (a) (b) Consisting of an inorganic substance containing a mixture with the aggregate of (d), wherein the surface layer is composed of (d) Si and O, and
Amorphous material consisting of (e) crystalline SiO ₂ and / or MO
₂ , or (f) an inorganic material containing a mixture of the amorphous material of (d) and the crystalline material of (e), and a thickness T of the surface layer ( A laminate of inorganic fibers satisfying T = aD (where a is a numerical value in the range of 0.023 to 0.053, and D is the diameter of the inorganic fibers (unit μm)) is expressed by (g ) Vacuum sealed in a metal or glass container, and in an inert gas atmosphere at a temperature in the range of
Treat under isostatic pressure of 0000 kg / cm ² or set in a carbon die, and in an inert gas atmosphere, 800 to 190
After hot-pressing under a pressure of 100 to 1000 kg / cm ² at a temperature in the range of 0 ° C., take out the processed aggregate of inorganic fibers from a metal or glass container, or from a carbon die, in an inert gas atmosphere. either treated with isotropic pressure of 1000~10000kg / cm ² at a temperature in the range of 1,550-2,000 ° C., or, (h) is set to carbon die, in an inert gas atmosphere, the range of 1500 to 2000 ° C. Hot-pressing under a pressure of 100 to 1000 kg / cm ² at a temperature of (i) surface treatment of the obtained inorganic fiber-bound ceramics, characterized in that the surface has a ten-point average roughness (Rz) of 5 μm (standard A method for producing an inorganic fiber-bound ceramic having a length of 3 mm or less is provided.

Furthermore, according to the present invention, (a) a polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more or a heat-reacted product thereof comprises a metal element of group 2A, 3A or 3B. A first step of preparing at least one metal element-containing organosilicon polymer selected from the group, (b) a second step of melt-spinning the metal element-containing organosilicon polymer to obtain a spun fiber, (c) a spun fiber The oxygen containing atmosphere in 50 ~ 170 ℃
The third step of preparing the infusibilized fiber by heating in (d) infusible fiber, or a preliminary shape from the mineralized fiber obtained by mineralizing the infusible fiber in an inert gas, and put this in a mold Charge, vacuum, in an atmosphere consisting of at least one selected from the group consisting of an inert gas, a reducing gas and a hydrocarbon, 1700 to 220
The surface has a ten-point average roughness (Rz) of 5 μm (reference length), which comprises a fourth step of applying pressure in a temperature range of 0 ° C., and a fifth step of (e) surface-treating the obtained inorganic fiber-bound ceramics. 3 mm) or less is provided.

Further, according to the present invention, there is provided a high-precision member made of the above-mentioned inorganic fiber-bound ceramics.

The present invention proposes two types of inorganic fiber-bound ceramics having different internal structures. First, the inorganic fiber-bonded ceramic according to claim 1 of the present invention will be described. The inorganic fibers are (a) an amorphous substance composed of Si, M, C and O, (b) crystalline fine particles of β-SiC, MC and C, and SiO 2.
₂ and an aggregate of MO ₂ and an amorphous material (M represents Ti or Zr), or (c) a mixture of the amorphous material of (a) and the aggregate of (b). You. β-SiC and MC in (b) can also exist as a solid solution thereof, and MC exists as MC _1-x (x is a number of 0 or more and less than 1) in a carbon-deficient state. You can also. The ratio of each element constituting the inorganic fiber is usually Si: 30 to 60% by weight, M: 0.5 to
35% by weight, preferably 1 to 10% by weight, C: 25 to 40% by weight, O:
It is 0.01 to 30% by weight. The equivalent diameter of inorganic fibers is generally 5
2020 μm.

The inorganic fiber is present in the inorganic fiber-bound ceramic of the present invention in an amount of 80% by volume or more, preferably 85 to 91% by volume. On the surface of each inorganic fiber, amorphous and / or crystalline carbon is in the range of 1 to 1000 nm, preferably 10 to 3 nm.
It is formed as a boundary layer with a thickness of 00 nm in an inconsistent layer. Then, (d) an amorphous substance composed of Si and O, and possibly M, and (e) a crystalline substance composed of crystalline SiO ₂ and / or MO ₂ so as to fill the gaps of the inorganic fibers. Or (f) an inorganic substance of a mixture of the amorphous substance of (d) and the crystalline substance of (e). That is, amorphous and / or crystalline carbon is present in a layered manner at the boundary between the inorganic fibers and at the boundary between the inorganic substance and the inorganic fiber in an inconsistent manner.

Further, in the above-mentioned inorganic substance, crystalline fine particles composed of MC having a particle diameter of 100 nm or less, or crystalline fine particles composed of MC having a particle diameter of 100 nm or less and MC having a particle diameter of more than 100 nm to 1000 nm are included. Crystalline particles are dispersed. Also,
In the carbon layer, crystalline particles made of MC having a particle size of 1000 nm or less are dispersed. Crystalline particles of MC having a particle size of more than 100 nm to 1000 nm contained in the inorganic substance and in the carbon layer are preferably mixed at 0.01 to 5% by volume. Also, 10
It is preferable to mix 0.1 to 5% by volume of crystalline fine particles made of MC having a particle size of 0 nm or less.

Next, the inorganic fiber-bonded ceramic according to the second aspect of the present invention will be described. The fiber material constituting the inorganic fiber-bonded ceramics according to claim 2 mainly has a sintered structure of SiC crystals, and in a region where sintering is excellent, a strong interface strength is exhibited between the SiC crystals. Proceeds within the crystal grains. Observation of the fracture surface of the fibrous material constituting this bonded body shows that such intragranular fracture of SiC is observed in at least 30% or more of the cross section of the fibrous material. In the fracture surface of the fibrous material, a favorable sintered region observed due to intragranular fracture between SiC crystals and an intragranular fracture region may be mixed.

[0016] The fibrous material contains at least one metal atom selected from the group consisting of group 2A, group 3A and group 3B metal elements. The ratio of the elements constituting the fiber material is usually S
i: 55 to 70% by weight, C: 30 to 45% by weight, M (metal element of Group 2A, 3A and 3B): 0.05 to 4.0% by weight, preferably 0.
It is 1 to 2.0% by weight. Among the metal elements of groups 2A, 3A and 3B, particularly preferred are Be, Mg, Y, Ce, B, and Al, all of which are known as sintering aids for SiC. There are chelate compounds and alkoxide compounds that can react with the Si—H bond of the silicon polymer. If the proportion of the metal is too small, sufficient crystallinity of the fiber material cannot be obtained, and if the proportion is too high, the intergranular fracture will increase and the mechanical properties will decrease.

All or most of the above-mentioned fiber material is deformed into a polygonal shape and is filled in a state very close to the close-packed structure. Further, in the boundary region between fibers, a boundary layer mainly composed of carbon of 1 to 50 nm is formed, and the strength at 1600 ° C. is 80% of room temperature strength, reflecting the structure shown above.
It exhibits extremely high mechanical properties of at least%.

The above-mentioned fibrous material has the same orientation as the laminated state of the sheet-like materials aligned in one direction, the same orientation as the laminated state of the two-dimensional fabric, and the same orientation as the three-dimensional fabric. State, or a randomly oriented state, or a composite structure thereof. These are temporarily selected depending on the mechanical properties required for the target shape.

What is important in common with the inorganic fiber-bound ceramics of the first and second aspects of the present invention is that the porosity of the inorganic fiber-bound ceramics is extremely low at 2% or less, so that honing, lapping, etc. Surface has 10-point average roughness (Rz) 5μm (standard length 3mm)
It is possible to finish as follows, which means that voids such as pores are not exposed on the surface. In addition to this, the stress (load) -displacement (strain) curve shows nonlinear behavior in the fracture test and does not break immediately, so that even if a crack occurs on the surface, it does not reach the final failure in one machine. It is.

Next, a method for producing the inorganic fiber-bound ceramics of the present invention will be described. Since the present invention proposes two types of inorganic fiber-bound ceramics, each will be described. First, a method for producing an inorganic fiber-bound ceramic according to claim 1 will be described. The inorganic fiber used as a raw material of the present invention is prepared by heating the inorganic fiber at a temperature in the range of 500 to 1600 ° C under an oxidizing atmosphere, for example, according to the method described in JP-A-62-289641. be able to. This inorganic fiber (M: Ti) is commercially available from Ube Industries, Ltd. as Tyranno Fiber (registered trademark). There is no particular limitation on the form of the inorganic fiber,
It may be a continuous fiber, a chopped short fiber obtained by cutting the continuous fiber, or a sheet-like material or woven fabric in which the continuous fibers are aligned in one direction.

The above fibers are subjected to a heat treatment in an oxidizing atmosphere such as air, pure oxygen, ozone, water vapor or carbon dioxide to form a surface layer of inorganic fibers. The thickness T (μm) of the surface layer of the inorganic fiber is T = aD (where a is 0.023 to 0.053
Where D is the diameter of the inorganic fiber (unit: μm)
It is. It is necessary to select heat treatment conditions so as to satisfy ()). By strictly controlling the thickness of the surface layer within the above range, an extremely dense inorganic fiber-bound ceramic having a porosity of 2% or less can be prepared.

Thus, the inorganic fiber comprises an inner surface layer and a surface layer, wherein the inner surface layer comprises (a) an amorphous substance comprising Si, M, C and O, (b) β-SiC, MC and Aggregate of crystalline ultrafine particles of C and amorphous materials of SiO ₂ and MO ₂ (M is T
Indicates i or Zr. ) Or (c) the amorphous material of (a) above and
(b) an amorphous substance comprising a mixture with the aggregate of (b), wherein the surface layer is composed of (d) an amorphous substance composed of Si and O, and optionally M; (e) crystalline SiO ₂ and / or MO ₂ , or (f) an inorganic substance containing a mixture of the amorphous substance of (d) and the crystalline substance of (e),
And the thickness T (unit μm) of the surface layer is T = aD (where a is 0.02
It is a numerical value within the range of 3 to 0.053, and D is the diameter (unit: μm) of the inorganic fiber. An inorganic fiber satisfying (3) is obtained.

In the present invention, a laminate comprising the above-mentioned inorganic fibers is prepared, and then formed into a predetermined shape, and then a metal such as Ti and its alloys, Ta and its alloys, stainless steel and mild steel, or silica glass, Pyrex, vacuum sealed in a glass container such as crystallized glass, and subjected to the first stage treatment under hot isostatic pressing to obtain a semi-finished product in which a laminate made of inorganic fibers is completely densified . The temperature of hot isostatic pressing is in the range of 800 to 1600 ° C,
The isotropic pressure is in the range 1000-10000 kg / cm ² . Alternatively, in the present invention, a laminate made of the above-mentioned inorganic fibers is prepared, set on a carbon die, and heated to 800 to 1900 ° C.
By hot-pressing at a temperature in the range of 100 to 1000 kg / cm ² and a pressure in the range of 100 to 1000 kg / cm ² , a semi-finished product in which the laminate of inorganic fibers is completely densified can be obtained.

Next, a semi-finished product in which the laminate made of inorganic fibers is completely densified is taken out of the container or the carbon die, and heated in an inert gas atmosphere at a temperature in the range of 1550 to 2000 ° C. and 1000 to 10000 kg / cm ² . Work up again under isostatic pressing.

Alternatively, a laminate made of the above-mentioned inorganic fibers is set in a carbon die, and is placed in an inert gas atmosphere.
Hot pressing at a temperature in the range of 1500 to 2000 ° C. and under a pressure of 100 to 1000 kg / cm ² .

Thereafter, the obtained inorganic fiber-bonded ceramic is cut into a predetermined shape, and the surface is honed or lapped to make the surface have a ten-point average roughness (Rz) 5.
Finish up to μm (standard length 3mm) or less.

Next, a method for producing an inorganic fiber-bound ceramic according to claim 2 will be described. This manufacturing method comprises the steps of (a)
Polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more or a heat-reacted product thereof, at least one selected from the group consisting of group 2A, group 3A and group 3B metal elements.
A first step of preparing one kind of metal element-containing organosilicon polymer, (b) a second step of melt-spinning the metal element-containing organosilicon polymer to obtain a spun fiber, and (c) the spun fiber in an oxygen-containing atmosphere. The third step of preparing the infusible fiber by heating at 50 to 170 ° C.
(d) Infusible fiber, or a preform is manufactured from mineralized fibers obtained by mineralizing infusible fibers in an inert gas, charged in a mold, vacuum, inert gas, reducing gas and hydrocarbons. A fourth step of applying pressure in a temperature range of 1700 to 2200 ° C. in an atmosphere of at least one selected from the group consisting of: (e) a fifth step of surface-treating the obtained inorganic fiber-bound ceramics.

First Step In the first step, a metal-containing organosilicon polymer as a precursor polymer is prepared. Polysilane, for example, according to the method described in `` Chemistry of Organosilicon Compounds '' Chemistry Doujin (1972), 1
A chain or cyclic polymer obtained by subjecting more than one kind of dichlorosilane to a dechlorination reaction using sodium, and its number average molecular weight is usually 300 to 1,000.
The polysilane in the present invention can have a hydrogen atom, a lower alkyl 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 1.5 or more in a molar ratio. It is necessary to be. If this condition is not satisfied, all of the carbon in the fibers is desorbed as carbon dioxide in the process of raising the temperature up to sintering together with the oxygen introduced during infusibility, and no boundary carbon layer between the fibers is formed. It is not preferable.

The polysilane in the present invention includes an organosilicon polymer partially obtained by heating the above-mentioned chain or cyclic polysilane and having a carbosilane bond in addition to a polysilane bond unit. Such an organosilicon combination can be prepared by a method known per se. Examples of the preparation method include a method of heating and reacting a linear or cyclic polysilane at a relatively high temperature of 400 to 700 ° C., and adding a phenyl group-containing polyborosiloxane to this polysilane to a relatively low temperature of 250 to 500 ° C. And a heat reaction method. The number average molecular weight of the organosilicon polymer thus obtained is usually from 1,000 to 5,000.

The phenyl-containing polyborosiloxane can be prepared according to the methods described in JP-A-53-42300 and JP-A-53-50299. For example, phenyl-containing polyborosiloxanes can be prepared by the dehydrochlorination condensation reaction of boric acid with one or more diorganochlorosilanes, the number average molecular weight of which is usually from 500 to 10,000. The amount of the phenyl group-containing polyborosiloxane is usually 15 parts by weight or less based on 100 parts by weight of the polysilane.

A predetermined amount of a compound containing a metal element belonging to Group 2A, 3A or 3B is added to polysilane, and the mixture is reacted in an inert gas at a temperature usually in the range of 250 to 350 ° C. for 1 to 10 hours. By doing so, a metal element-containing organosilicon polymer as a raw material can be prepared. The metal element is used in such a manner that the content ratio of the metal element in the finally obtained sintered SiC fiber composite is 0.05 to 4.0% by weight, and the specific ratio is appropriately determined by those skilled in the art according to the teachings of the present invention. Can be determined. Further, the metal element-containing organosilicon polymer,
A crosslinked polymer having a structure in which at least a part of silicon atoms of polysilane is bonded to a metal atom via or without an oxygen atom.

As the compound containing a metal element of group 2A, 3A or 3B added in the first step, alkoxide, acetylacetoxide compound, carbonyl compound, cyclopentadienyl compound or the like of the metal element is used. Examples thereof include beryllium acetylacetonate, magnesium acetylacetonate, yttrium acetylacetonate, cerium acetylacetonate, butoxide borate, and aluminum acetylacetonate. Each of these has a structure in which each metal element is bonded to Si directly or via another element by reacting with a Si-H bond in an organosilicon polymer generated upon reaction with polysilane or a heated reactant thereof. Can be generated.

Second Step In the second step, a spun fiber of a metal element-containing organosilicon polymer is obtained. A spun fiber can be obtained by spinning a metal element-containing organosilicon polymer as a precursor polymer by a method known per se such as melt spinning and dry spinning.

Third Step In the third step, the spun fiber is placed in an oxygen-containing atmosphere at 50 to 1
Heat at 70 ° C to prepare infusible fibers. The purpose of the infusibilization is to form a bridge point by oxygen atoms between the polymers constituting the spun fibers so that the infusibilized fibers do not melt and the adjacent fibers do not fuse together in the subsequent mineralization step. It is to be. As the gas constituting the oxygen-containing atmosphere, the infusibilization time depends on the infusibilization temperature, but usually,
A few minutes to 30 hours. The oxygen content in the infusible fiber is 8
It is desirable to control the amount to be about 16% by weight. Most of this oxygen remains in the fibers even after mineralization in the next step, and plays an important role in desorbing excess carbon in the inorganic fibers as CO gas in the temperature rising process until final sintering. I do. If the oxygen content is less than 8% by weight, excess carbon in the inorganic fibers remains more than necessary and segregates around the SiC crystal during the heating process to stabilize.
When the sintering of C is inhibited, and when the content is more than 16% by weight, surplus carbon in the inorganic fibers is completely eliminated, so that a boundary carbon layer between the fibers is not generated. All of these adversely affect the mechanical properties of the resulting material.

It is preferable that the infusible fiber is further preheated in an inert atmosphere. Examples of the gas constituting the inert atmosphere include nitrogen and argon. The heating temperature is usually 150-800 ° C., and the heating time is only a few minutes to 20 hours. By preheating the infusibilized fiber in an inert atmosphere, while preventing incorporation of oxygen into the fiber, the crosslinking reaction of the polymer constituting the fiber is further advanced, and the infusibilized fiber from the precursor polymer is formed. The strength can be further improved while maintaining excellent elongation, whereby the mineralization in the next step can be stably performed with good workability.

Fourth Step In the fourth step, the infusibilized fiber is continuously or batchwise treated in an inert gas atmosphere such as argon at 1000 to 1700.
Heat treatment at a temperature in the range of ° C. to mineralize.

Next, the mineralized fiber is formed into a sheet shape, a woven shape or a chop shape, and a preliminary shape made of at least one of them is produced. Next, the preform is charged into a mold and pressurized in a temperature range of 1700 to 2200 ° C. in an atmosphere composed of at least one selected from the group consisting of vacuum, inert gas, reducing gas and hydrocarbon. still,
In the heating process up to pressurization in the fourth step, the CO
A pressurization program according to the desorption speed of the gas may be incorporated.

In the fourth step, a preform is manufactured from the infusibilized fiber, and the preform is placed in a press mold.
The same method as described above may be performed except that the mineralization is performed in the same mold.

Fifth Step After the fourth step, the binder is taken out of the mold, cut into a predetermined shape, and the surface of the binder is honed or lapped to have a ten-point average roughness (Rz) of 5 μm (reference length). 3m
m) Finish below.

[0040]

EXAMPLES Examples and comparative examples are shown below to explain the present invention in more detail. In the following, the mechanical properties of the final product were measured as follows. [Evaluation of Mechanical Properties] A stress (load) -displacement (strain) curve was measured using an autograph manufactured by Shimadzu, and the maximum bending strength was determined. The test piece is 4mm wide, 3mm high, 40 length
mm. To evaluate the fracture resistance, a test piece with a chevron notch (width 4 mm, height 3 mm, notch: 0.8 mm <
The stress-displacement curve was measured by a three-point bending test (crosshead speed 0.05 mm / min) using a ligament tip> -2.8 mm), and the fracture energy was calculated from the area.

[Evaluation of surface smoothness] manufactured by Tokyo Seimitsu
Using a surface roughness meter, measure the 10-point average roughness (R
z) was measured.

Example 1 Tyranno fibers having a fiber diameter of 10 μm (registered trademark: manufactured by Ube Industries, Ltd.) were subjected to heat treatment in air at 950 ° C. for 15 hours to produce inorganic fibers comprising a surface layer and an inner layer. A = 0.030 on the fiber surface
, A uniform surface layer having an average of about 300 nm was formed. Next, a sheet in which the inorganic fibers were oriented in one direction was prepared, cut into 100 mm × 100 mm, and 50 sheets were alternately laminated at 0/90 °, set in a carbon die, and placed under an argon atmosphere. Hot pressing was performed at a temperature of 1800 ° C. and a pressure of 500 kgf / cm ² to obtain an inorganic fiber-bound ceramic. afterwards,
The bonded body was cut into a predetermined test piece size, and the surface was lapped to obtain the inorganic fiber-bound ceramic of claim 1.

The surface of the obtained inorganic fiber-bound ceramics was observed. FIG. 1 shows a photograph of the surface of the inorganic fiber-bound ceramics. The conjugate was very dense and no pores were observed. The surface roughness of the test piece was Rz = 4.08
μm.

FIG. 2 shows a stress-displacement curve of this inorganic fiber-bound ceramic in a bending test at room temperature and at 1400 ° C.
Show. The stress-displacement curve of inorganic fiber bonded ceramics is
It shows non-linear behavior and no immediate destruction has occurred.
The breaking energy determined by a three-point bending test using a test piece with a chevron notch was 2350 J / m ² .

In a fracture test of a silicon nitride or silicon carbide smooth material, the stress-displacement curve shows a linear behavior and breaks immediately at the maximum load. Also, "Fine Ceramics, p.981 (1993) Fine Ceramics Technology Research Association,
According to Takayuki Fukasawa et al., The fracture energy of composite silicon carbide to which whisker is added for the purpose of improving the fracture resistance is reported to be 200 J / m ² or less. It can be seen that the inorganic fiber-bonded ceramic of claim 1 has excellent fracture resistance.

Example 2 First, 1 L of dimethyldichlorosilane was added dropwise to anhydrous xylene containing 400 g of sodium while heating and refluxing xylene under a stream of nitrogen gas, followed by heating under reflux for 10 hours to form a precipitate. This precipitate was filtered, and methanol,
Then, it was washed with water to obtain 420 g of white polydimethylsilane. Next, 750 g of diphenyldichlorosilane and 124 g of boric acid were added in a nitrogen gas atmosphere in n-butyl ether to 100 g.
The resulting white resinous material was further heated at 400 ° C. for 1 hour in a vacuum to obtain 530 g of a phenyl group-containing polyboroxane. 4 parts of this phenyl group-containing polyborosiloxane was added to 100 parts of the polydimethylsilane obtained above, and thermally condensed at 350 ° C. for 5 hours in a nitrogen gas atmosphere to obtain a high molecular weight organosilicon polymer. A polyaluminocarbosilane was synthesized by adding 7 parts of aluminum-tri- (sec-butoxide) to a xylene solution in which 100 parts of the organosilicon polymer was dissolved, and performing a cross-linking reaction at 310 ° C. under a nitrogen gas stream. This 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. The infusibilized fiber was continuously fired at 1500 ° C. in nitrogen to synthesize silicon carbide continuous inorganic fiber. After preparing a laminate in which these fibers are aligned in one direction, and charged in a carbon die, a pressure of 50
Hot press molding was carried out at a pressure of 2000 ° C. at a pressure of MPa. The obtained molded product was cut into a predetermined shape, and the surface was wrapped to obtain the inorganic fiber-bound ceramic of claim 2.

The surface of the obtained inorganic fiber-bound ceramics was observed. FIG. 3 shows a photograph of the surface of the inorganic fiber-bound ceramics. The conjugate was very dense and no pores were observed. The surface roughness of the test piece was Rz = 1.05.
μm.

FIG. 4 shows a stress-displacement curve of this inorganic fiber-bound ceramic in a bending test at room temperature and at 1600 ° C.
Show. The inorganic fiber-bonded ceramic bears the stress even after exhibiting the maximum load, and does not break immediately.
The breaking energy obtained by a three-point bending test using a test piece with a chevron notch was 1200 J / m ² .

Comparative Example 1 A C / C composite material manufactured by Owada was cut to a predetermined size, and the surface was lapped in the same manner as the inorganic fiber-bound ceramics of the present invention.

The surface of the obtained C / C composite material was observed. FIG. 5 shows a photograph of the surface of the C / C composite material. This composite material contained pores and cracks, which were exposed on the surface of the test piece. Surface roughness is Rz = 5.72μm
In the pores, the measurement range was greatly exceeded. FIG. 6 shows a stress-displacement curve of the C / C composite material in a bending test at room temperature. This C / C composite material bears the stress even after exhibiting the maximum load, and does not cause immediate destruction.

[Brief description of the drawings]

FIG. 1 is an electron microscope photograph instead of a drawing showing a surface structure of an inorganic fiber-bound ceramic obtained in Example 1 of the present invention.

FIG. 2 is a diagram showing a relationship between stress and displacement of the inorganic fiber-bound ceramic obtained in Example 1 of the present invention.

FIG. 3 is an electron micrograph instead of a drawing showing a surface structure of the inorganic fiber-bound ceramic obtained in Example 2 of the present invention.

FIG. 4 is a diagram showing a relationship between stress and displacement of the inorganic fiber-bound ceramic obtained in Example 2 of the present invention.

FIG. 5 is an electron microscope photograph instead of a drawing showing the surface texture of the C / C composite material obtained in Comparative Example 1 of the present invention.

FIG. 6 is a diagram showing a relationship between stress and displacement of the C / C composite material obtained in Comparative Example 1 of the present invention.

Continuation of the front page (72) Inventor Toshihiro Ishikawa 5, 1978 Kogushi, Ube City, Ube City, Yamaguchi Prefecture Ube Research & Development Co., Ltd. Ube Research Laboratory F term (reference) 4G001 BA77 BA86 BB04 BB13 BB14 BB22 BB25 BB26 BB60 BB67 BB86 BC42 BC43 BC54 BE03 BE22 BE35 4L037 CS29 CS30 FA01 FA03 FA05 FA17 PA49 PS02 PS10 UA17

Claims (5)

[Claims] 1. A (a) Si, M, amorphous material consisting of C and O, with the crystalline particles of (b) β-SiC, MC and C, SiO ₂
And an aggregate of an amorphous material of MO ₂ (M represents Ti or Zr), or (c) an inorganic material containing a mixture of the amorphous material of (a) and the aggregate of (b). (D) an amorphous material consisting of Si and O, and possibly M, and (e) a crystalline material consisting of crystalline SiO ₂ and / or MO ₂ , which is present so as to fill the gaps between the fibers and the inorganic fibers. A substance, or (f) a mixture of the amorphous substance of (d) and the crystalline substance of (e), and
Inorganic substance in which crystalline fine particles composed of MC having a particle diameter of less than 100 nm are dispersed, or crystalline particles composed of MC having a particle diameter of less than 100 nm and crystalline particles composed of MC having a particle diameter of more than 100 nm to 1,000 nm are dispersed. Consisting of a substance, the content of the inorganic fiber is 80% by volume or more, and the inorganic fiber and the inorganic substance, and 10% as a boundary layer between the inorganic fibers.
Crystalline particles composed of MC having a particle size of 00 nm or less are dispersed 1
An inorganic fiber-bonded ceramic having a layer in which amorphous and / or crystalline carbon having a thickness of up to 1000 nm is inconsistently mixed, wherein the surface of the inorganic fiber-bound ceramic has a ten-point average roughness (Rz) of 5 μm ( Inorganic fiber-bonded ceramics having a reference length of 3 mm) or less, and exhibiting non-linear behavior in stress-displacement curves in a fracture test and not immediately breaking. 2. An inorganic fiber mainly comprising a crystal structure of SiC, wherein the inorganic fiber containing at least one metal atom selected from the group consisting of metal atoms of groups 2A, 3A and 3B is closest packed. To a structure very close to
An inorganic fiber-bound ceramic having a boundary layer mainly composed of carbon having a thickness of 〜50 nm and having a ten-point average roughness (Rz) of 5 μm (reference length of 3 m).
m) Inorganic fiber-bonded ceramics, characterized in that the stress-displacement curve shows a non-linear behavior in a fracture test and does not break immediately. 3. An inorganic fiber comprising an inner surface layer and a surface layer, wherein the inner surface layer comprises (a) an amorphous substance comprising Si, M, C and O, and (b) β-SiC, MC and C Crystalline ultrafine particles and SiO
₂ and an aggregate of MO ₂ and an amorphous material (M represents Ti or Zr), or (c) a mixture of the amorphous material of (a) and the aggregate of (b). Composed of inorganic substances
(d) an amorphous material consisting of Si and O, optionally M, (e) a crystalline material consisting of crystalline SiO ₂ and / or MO ₂ , or
(f) It is composed of an inorganic substance containing a mixture of the amorphous substance of the above (d) and the crystalline substance of the above (e), and the thickness T (unit μm) of the surface layer is T = aD ( Here, a is a numerical value within the range of 0.023 to 0.053, and D is a diameter of the inorganic fiber (unit: μm).) Sealed, in an inert gas atmosphere, 800-1
Treat at a temperature in the range of 600 ° C under an isostatic pressure of 1000 to 10,000 kg / cm ² or set in a carbon die, and in an inert gas atmosphere, at a temperature in the range of 800 to 1900 ° C,
After hot-pressing under a pressure of 00 kg / cm ² , take out the processed aggregate of inorganic fibers from a metal or glass container or from a carbon die, and in an inert gas atmosphere, a temperature in the range of 1550 to 2000 ° C. in either processed with isotropic pressure of 1000~10000kg / cm ^2, or, (h) is set to carbon die, in an inert gas atmosphere, 100 to 1000 / cm ² at a temperature in the range of 1500 to 2000 ° C. (I) Surface treatment of the obtained inorganic fiber-bound ceramics characterized by the fact that the surface has a ten-point average roughness (Rz) of 5 μm
(Reference length: 3 mm) A method for producing an inorganic fiber-bound ceramic having a length of not more than 3 mm. (A) a polysilane having a molar ratio of carbon atoms to silicon atoms of 1.5 or more, or a heat-reacted product thereof, comprising at least one metal selected from the group consisting of group 2A, 3A, and 3B metal elements; The first step of preparing a kind of metal element-containing organosilicon polymer, (b) the second step of melt-spinning the metal element-containing organosilicon polymer to obtain a spun fiber, (c) the spun fiber in an oxygen-containing atmosphere 50 The third step of preparing the infusible fiber by heating at ~ 170 ° C, (d) preparing a preform from the infusible fiber, or the mineralized fiber obtained by mineralizing the infusible fiber in an inert gas, In a mold, vacuum, an inert gas, a reducing gas and at least one selected from the group consisting of hydrocarbons, in an atmosphere consisting of at least one, pressurized in a temperature range of 1700 to 2200 ° C., the fourth step, (e) obtained Characterized in that it consists of a fifth step of surface-treating inorganic fiber-bound ceramics That the surface ten-point average roughness (Rz) 5 [mu] m (reference length 3mm) method for producing a less is inorganic fibers bonded ceramics. 5. A high-precision member comprising the inorganic fiber-bonded ceramic according to claim 1 or 2.