JP2000288916A - Jig for polishing treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jig for polishing treatment, light in weight and capable of maintaining dimension accuracy and a compressive strength necessary during polishing for a long time. SOLUTION: A jig for polishing treatment is made of an Si-SiC composite material or an CiC composite material. The Si-SiC base composite material contains silicon, silicon carbide, carbon fiber and a carbon component other than carbon fiber, and has a structure composed of a frame portion and silicon and silicon carbide phases formed around the frame portion. The SiC base composite material contains silicon carbide, carbon fiber and a carbon component other then carbon fiber, and has a structure composed of a frame portion and silicon carbide phases having a different grade of connection with carbons and formed around the frame portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing jig used for a polishing apparatus for producing a ceramic product having a constant thickness, high parallelism and high flatness.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a ceramic product with high accuracy of constant thickness, parallelism and flatness, for example,
The polishing apparatus 20 shown in FIG. 4 is used. In this polishing apparatus, a circular mount plate 22 is fixed to the lower surface of a pressurizing head 21 supported on a plurality of head rotating shafts 27 that can rotate and ascend and descend, and a ceramic product 23 is mounted on the lower surface of these mount plates 22. Multiple sheets are stuck. A polishing pad 25 is attached to the upper surface of the circular platen 26, and the platen 26 and the pressure head 21 rotate independently of each other. The ceramic product 23 is polished by a polishing cloth 25 while a predetermined pressure is applied by the pressure head 21. At this time, the surface plate 2 used above
As the jigs for the polishing treatment such as 6 and the mount plate 22, those made of cast iron or alumina having good dimensional accuracy have been mainly used.

[0003] However, the above-mentioned polishing jig includes:
In addition to thermal deformation due to polishing heat and wear during polishing, cracks are likely to occur during handling, particularly when using alumina, and the quality and productivity of the proper polished surface of the ceramic product 23 In order to obtain this, it was necessary to modify or replace the polishing jig. Also,
These jigs are very heavy and burden the operator. From the above, the downtime of the polishing device becomes longer,
There has been a problem that the productivity and yield of ceramic products are reduced.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such problems of the related art,
The aim is to provide a polishing jig that not only maintains the dimensional accuracy and compressive strength required for polishing for a long period of time, but also can improve the productivity and yield of ceramic products because it is lightweight. Is what you do.

[0005]

That is, according to the present invention, at least carbon is composed of 55 to 75% by weight of carbon, 1 to 10% by weight of silicon, and 10 to 50% by weight of silicon carbide. A yarn aggregate containing a bundle of fibers and a carbon component other than carbon fibers is three-dimensionally combined while being oriented in the layer direction, and is integrated so as not to be separated from each other. A matrix made of a Si-SiC-based material filled between adjacent yarns, and having a dynamic friction coefficient of 0.05 to 0.6;
There is provided a polishing jig comprising a Si-SiC-based composite material having a porosity controlled to 10% to 10%.

At this time, in the present invention, the matrix preferably includes a silicon carbide phase generated along the surface of the yarn, and the matrix includes a silicon phase composed of silicon, and the silicon phase It is preferable that the silicon carbide phase is formed between the yarn and the yarn, and it is preferable that the matrix has a gradient composition in which the content ratio of silicon increases as the distance from the yarn increases.

In the present invention, the yarn aggregate includes a plurality of yarn arrays, and each of the yarn arrays is formed by two-dimensionally arranging the plurality of yarns substantially in parallel. It is preferable that the yarn aggregate is formed by stacking the array, and that the matrix forms a three-dimensional network structure by being continuous with each other in the Si-SiC composite material. .

Further, according to the present invention, a SiC-based composite material comprising silicon carbide, carbon fiber, and a carbon component other than carbon fiber, and having a structure including a skeleton and a matrix formed around the skeleton. Wherein at least 50% of the silicon carbide is β-type, the skeleton is formed of carbon fibers and carbon components other than carbon fibers, and a part of the skeleton is carbonized. Silicon may be present, the matrix is formed of silicon carbide, the matrix and the skeleton are integrally formed, and the SiC-based composite material has 0.5 to 5% of pores. The present invention provides a polishing jig characterized by having a distribution of an average pore diameter with a ratio of two peaks.

At this time, in the present invention, it is preferable that the matrix is formed along the surface of the skeleton portion, and that the matrix has a gradient composition in which the silicon content increases as the matrix moves away from the surface of the skeleton portion. Is preferred.

Further, in the present invention, at least a plurality of yarns whose skeletons are made of carbon fibers and carbon components other than carbon fibers are two-dimensionally arranged almost in parallel, and the yarn arrays are alternately orthogonally crossed. It is preferable that the matrix is formed of a yarn aggregate that is produced by laminating the required number of layers, and that the matrix is continuous with each other in the SiC-based composite material to form a three-dimensional network structure. Is preferred.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polishing jig of the present invention
The main feature is that it is formed of an i-SiC-based composite material or a SiC-based composite material. As a result, the required dimensional accuracy (dimensional error: ±
0.2 mm, flatness: 0.01 mm or less, flatness [Rma
x]: 3 μm or less and compressive strength (200 MPa or more) for a long period of time, and the jig for polishing treatment of the present invention is made of a Si—SiC composite material or a SiC composite material. In addition to improving the toughness and preventing cracking during handling, the weight can be reduced to half or less.
From the above, the polishing jig of the present invention hardly needs to modify or replace the polishing jig, so that the productivity and yield of ceramic products can be improved. Note that the polishing jig of the present invention is preferably, for example, a surface plate, a mount plate, a carrier used for simultaneous double-side polishing, and the like.

Here, the composite material used in the present invention will be described in more detail. The C / C composite forming the skeleton of the composite material used in the present invention is lightweight, as well as having excellent toughness, excellent impact resistance, high hardness, high thermal conductivity and high heat dissipation. The C / C composite is a material in which a matrix of carbon is formed in a gap between carbon fibers arranged in two-dimensional or three-dimensional directions, and a carbon fiber is contained in an amount of 10 to 70%. If
The rest is boron nitride, boron, copper, bismuth, titanium,
It may contain one or more substances selected from the group consisting of chromium, tungsten, and molybdenum.

When the C / C composite is used as a skeleton of a composite material, since these substances have lubricity, they are contained in a base material made of the C / C composite to form a Si—SiC-based material or a SiC-based material. Even in the part of the base material impregnated with the material, the lubricity of the fiber can be maintained, and a decrease in toughness can be prevented. For example, the content of boron nitride is preferably 0.1 to 40% by weight based on 100% by weight of the base material made of the C / C composite. If the amount is less than 0.1% by weight, the effect of imparting lubricity by boron nitride cannot be sufficiently obtained, and if it exceeds 40% by weight, the brittleness of boron nitride also appears in the composite material.

Further, when a C / C composite is used as the skeleton of the composite material, a plurality of yarn arrays are provided, and each yarn array arranges the plurality of yarns approximately two-dimensionally substantially in parallel. Is formed,
It is preferable that a yarn aggregate is formed by laminating each yarn array. As a result, the composite material has a laminated structure in which a plurality of yarn arrays are laminated in one direction.

Further, when a C / C composite is used as the skeleton portion of the composite material, it is more preferable that the longitudinal directions of the yarns in the adjacent yarn arrays cross each other, preferably, cross each other. Thereby, even after the matrix is formed, the carbon fibers are not shortened, so that the mechanical strength is maintained, and the carbon fibers are formed of free carbon formed in the skeleton without causing anisotropy of the shape. The matrix is also highly uniform.

Here, the C / C composite is usually formed by bundling hundreds to tens of thousands of carbon fibers having a diameter of about 10 μm to form a fiber bundle (yarn), and covering the fiber bundle with a thermoplastic resin. A flexible thread-like intermediate material prepared as described above is obtained, formed into a sheet by the method described in JP-A-2-80639, and the sheet-like material is arranged in a two-dimensional or three-dimensional direction. A preform (fiber preform) of a predetermined shape is formed by forming a directional sheet (UD sheet) or various cloths, or laminating the above sheets or cloths, and forming the outer periphery of a fiber bundle of the preform. What is necessary is just to use what is obtained by baking a coating of a thermoplastic resin or the like made of an organic substance and removing the above coating by carbonization. In the C / C composite, the carbon component other than the carbon fibers in the yarn is preferably a carbon powder, particularly preferably a graphitized carbon powder.

Next, using the C / C composite or the preform, the following composite materials are manufactured. The Si—SiC-based composite material, which is a composite material used in the present invention, is composed of 55 to 75% by weight of carbon, 1 to 10% by weight of silicon, and 10 to 50% by weight of silicon carbide. And a yarn assembly containing a carbon component other than the carbon fiber are three-dimensionally combined while being oriented in the layer direction, and are integrated so as not to be separated from each other. A matrix of Si-SiC-based material filled between the mating yarns, a dynamic friction coefficient of 0.05-0.6,
Porosity controlled to 0.5 to 10%. This Si-SiC composite material is disclosed in Japanese Patent Application No. Hei 10-26.
No. 7462 (filed on Sep. 4, 1998).

Here, the Si—SiC-based material includes several different phases from a silicon phase remaining in an unreacted state to a substantially pure silicon carbide.
Typically, it is composed of a silicon phase and a silicon carbide phase, but the silicon carbide phase refers to a phase that can include a SiC coexisting phase in which the content of silicon is inclined. Therefore, the Si-SiC-based material is a general term for materials contained in the range of 0 to 50 mol% as the concentration of carbon in the Si-SiC series. In addition, the Si-SiC-based composite material is
The matrix portion is formed of the above-mentioned Si-SiC-based material.

In the Si—SiC-based composite material, preferably, the matrix has a silicon carbide phase generated along the surface of the yarn, whereby the strength of each yarn itself is further improved, It is preferable because it is difficult to break.

Further, the Si—SiC-based composite material includes
It is preferable that the matrix has a silicon phase composed of silicon, and that a silicon carbide phase be generated between the silicon phase and the yarn, and a gradient composition in which the content ratio of silicon increases as the distance from the surface of the yarn increases. It is more preferred to have a matrix having This is because the surface of the yarn is strengthened by the silicon carbide phase, and the central portion of the matrix is made of a silicon phase having relatively low hardness, so that microscopic stress dispersion is further promoted.

As a result, the Si—SiC-based composite material can be rapidly heated from room temperature (20 ° C.) to 700 ° C. for 2 minutes, maintained at the same temperature for 5 minutes, and naturally cooled by standing at room temperature. When the cycle was repeated 15 times, the weight reduction ratio after the test was 8 times less than the weight before the test was started.
%, Preferably 5% or less (in the case of 600 ° C. or more), and the retention of the strength after the test to the strength before the start of the test when tested according to JIS R1601 is 80% or more, preferably 85% or more. %, It is possible not only to reduce the characteristic fluctuation due to the ambient change, but also to reduce the amount of wear under high temperature conditions by 50 ° C.
At 1.0% / hour or less, preferably 0.6% / hour or less, so that excellent wear resistance (specific wear amount:
0.0-0.3 mm / N · km).

Here, the Si—SiC-based composite material will be further described with reference to the drawings. FIG. 1 is a perspective view schematically showing a yarn aggregate which is a skeleton of a composite material used in the present invention, and FIG. 2 shows an example of a structure of a Si—SiC-based composite material used in the present invention. Yes, (a) Fig. 1
FIG. 2B is a cross-sectional view taken along line IIa-IIa in FIG. 1, and FIG. 2B is a cross-sectional view taken along line IIb-IIb in FIG. The skeleton of the Si—SiC-based composite material 7 is constituted by the yarn aggregate 6. The yarn aggregate 6 includes the yarn arrays 1A, 1B, 1C, 1D, 1
E and 1F are vertically stacked. In each yarn array, the yarns 3 are two-dimensionally arranged, and the longitudinal directions of the yarns are substantially parallel. The longitudinal direction of each yarn in each vertically arranged yarn array is orthogonal. That is, the longitudinal direction of each yarn 2A of each yarn array 1A, 1C, 1E is parallel to each other, and is orthogonal to the longitudinal direction of each yarn 2B of each yarn array 1B, 1D, 1F. Each yarn is composed of a fiber bundle 3 made of carbon fiber and a carbon component other than carbon fiber. The yarn assembly 6 having a three-dimensional lattice shape is formed by stacking the yarn arrays. Each yarn is crushed during a pressure forming process as described below, and has a substantially elliptical shape.

In each of the yarn arrays 1A, 1C, and 1E, a matrix 8A is provided between adjacent yarns.
And each matrix 8A extends along and parallel to the surface of the yarn 2A. In each of the yarn arrays 1B, 1D, and 1F, the gap between adjacent yarns is filled with a matrix 8B, and each matrix 8B extends along the surface of the yarn 2B and parallel thereto. In this example, the matrices 8A and 8B are respectively composed of silicon carbide phases 4A and 4B covering the surface of each yarn.
And Si-SiC-based material phases 5A and 5B having a lower carbon content than silicon carbide phases 4A and 4B. Silicon may be partially contained in the silicon carbide phase. In this example, silicon carbide phases 4A and 4B are also generated between yarns 2A and 2B that are vertically adjacent to each other. Each matrix 8A and 8B is elongated along the surface of the yarn, preferably in a straight line, and each matrix 8A and 8B is orthogonal to each other. The matrix 8A in the yarn arrays 1A, 1C, and 1E and the matrix 8B in the yarn arrays 1B, 1D, and 1F orthogonal to the matrix are continuous at the gap between the yarns 2A and 2B. As a result, matrix 8A,
8B forms a three-dimensional lattice as a whole.

Further, the Si—SiC-based composite material used in the present invention may be formed from a matrix layer in which a layer made of only silicon is formed near the surface. By simply coating the base material surface with the Si-SiC-based material, the layer made of the Si-SiC-based material is easily peeled off due to a difference in thermal expansion coefficient between the two under high-temperature oxidation conditions. By forming the SiC-based material as the matrix layer of the Si—SiC-based composite material, the strength in the laminating direction of the fibers is increased, and peeling can be prevented, so that the durability can be improved.

Here, the thickness of the matrix layer is preferably at least 0.01 mm. Further, it is preferably at least 0.05 mm, more preferably at least 0.1 mm. If the thickness of the matrix layer is less than 0.01 mm, sufficient durability cannot be provided under high oxidation conditions.

In the Si—SiC-based composite material used in the present invention, the Si concentration in the matrix layer preferably decreases from the surface toward the inside. By giving a gradient to the Si concentration in the matrix layer,
Corrosion resistance and strength in a strongly oxidizing corrosion environment, a healing function against defects in the surface layer portion and the inner layer portion can be remarkably improved, and deterioration of thermal stress of a material due to a difference in thermal expansion coefficient can be prevented. This is because the Si concentration in the surface layer is lower than the S concentration in the inner layer.
Because the i-concentration is relatively higher than the i-concentration, the generated microcracks are healed during heating and maintain oxidation resistance.

As described above, the Si—S used in the present invention
The iC-based composite material has the impact resistance, high hardness, and light weight of a C / C composite, and the oxidation resistance, spalling resistance, self-lubrication, and abrasion resistance of a Si-SiC-based material. In addition, since it also has self-healing properties, it can withstand long-term use under high-temperature oxidation conditions.

Further, the Si—SiC-based composite material used in the present invention can improve the dimensional accuracy in the longitudinal direction of the molded body, so that a large-sized thin member that cannot be produced by a silicon carbide-based material can be used. It can be manufactured relatively easily.

Next, the composite material S used in the present invention is
The iC-based composite material is composed of silicon carbide, carbon fiber, and a carbon component other than carbon fiber, and has a structure including a skeleton portion and a matrix formed around the skeleton portion. % Is β type, the skeleton is formed of carbon fiber and carbon components other than carbon fiber, and silicon carbide may be present in a part of the skeleton,
The matrix is formed of silicon carbide, the matrix and the skeleton are integrally formed, and 0.5 to 5
% Porosity and a two-peaked average porosity distribution.

As a result, the SiC-based composite material used in the present invention uses the C / C composite as the skeleton, and therefore, even if SiC is formed in a part thereof, the carbon fibers are used as carbon fibers. Is maintained without breaking, so that carbon fibers do not become short due to silicon carbide.
It has a great feature that the mechanical strength of the / C composite is almost maintained or is increased by silicon carbide. Moreover, the yarn assembly has a composite structure in which a matrix made of a SiC-based material is formed between adjacent yarns. In this point, it is different from the above-mentioned Si-SiC-based composite material. The SiC-based composite material can be manufactured by the method disclosed in Japanese Patent Application No. 11-31979 (filed on Feb. 9, 1999).

Here, the SiC-based material refers to a material containing silicon carbide having a different degree of bonding with carbon.
The iC-based material refers to one manufactured as follows.
In the SiC-based composite material of the present invention, the C / C composite is impregnated with metal silicon. At this time, the metal silicon contains carbon atoms and / or carbon atoms constituting carbon fibers in the composite.
Alternatively, since it reacts with the free carbon atoms remaining on the surface of the carbon fiber and is partially carbonized, the yarn between the outermost surface of the C / C composite and the carbon fiber,
Partially carbonized silicon is produced, thus forming a matrix of silicon carbide between the yarns.

This matrix may contain several different phases, from a silicon carbide phase in which a trace amount of silicon and carbon are bonded to a pure silicon carbide crystal phase. However, this matrix contains only metallic silicon below the X-ray detection limit (0.3% by weight).
That is, although this matrix is typically made of a silicon carbide phase, the silicon carbide phase may include a SiC-based phase in which the content of silicon is inclined. Therefore, the SiC-based material refers to a concentration of carbon of at least 0.01 mol% to 50 mol% in such a SiC series.
It is a general term for materials included in the range up to%. In addition, in order to control the carbon concentration to less than 0.01 mol%, in relation to the amount of free carbon in the C / C composite,
It is not practical because strict measurement of the amount of metallic silicon to be added is required and temperature control in the final step described later is complicated. Therefore, theoretically, the carbon concentration is 0.00
It is possible to control to about 1 mol%.

Here, the SiC-based composite material used in the present invention will be further described with reference to the drawings. FIG. 1 is a perspective view schematically showing a yarn aggregate which is a skeleton of a composite material used in the present invention, and FIG.
1 shows an example of the structure of a composite material, in which (a) is a cross-sectional view taken along line IIa-IIa in FIG. 1 and (b) is a cross-sectional view taken along line IIb-IIb in FIG. 1. It is sectional drawing.

The skeleton of the SiC-based composite material 12 is constituted by the yarn aggregate 6. Yarn aggregate 6
The yarn arrays 1A, 1B, 1C, 1D, 1E, 1F are vertically stacked. In each yarn array, the yarns 3 are two-dimensionally arranged, and the longitudinal directions of the yarns are substantially parallel. The longitudinal direction of each yarn in each vertically arranged yarn array is orthogonal. That is, each yarn 2 of each yarn array 1A, 1C, 1E
The longitudinal directions of A are parallel to each other and orthogonal to the longitudinal direction of each yarn 2B of each yarn array 1B, 1D, 1F. Each yarn is composed of a fiber bundle 13 composed of carbon fibers and carbon components other than carbon fibers. The yarn assembly 6 having a three-dimensional lattice shape is formed by stacking the yarn arrays. Each yarn is crushed during a pressing step, as described below, and is slightly oval.

In each of the yarn arrays 1A, 1C, and 1E, a matrix 8A is provided between adjacent yarns.
And each matrix 8A extends along and parallel to the surface of the yarn 2A. In each of the yarn arrays 1B, 1D, and 1F, the gap between adjacent yarns is filled with a matrix 8B, and each matrix 8B extends along the surface of the yarn 2B and parallel thereto. As shown in FIGS. 3A and 3B, each of the matrices 8A and 8B is made of a silicon carbide phase 14 covering the surface of each yarn.

Further, a part of silicon carbide phase 14 may protrude into the carbon fiber layer inside the composite member.
The median value of such small projections 9 is about 100 μm.
Are formed. In addition, since the small protrusions 9 are formed along the traces of the matrix composed mostly of carbon components other than the carbon fibers of the C / C composite as the raw material, the small protrusions 9 have a space between the yarns and / or a yarn arrangement. The density of the small protrusions 9 per unit area can be adjusted by appropriately selecting the distance from the yarn array. Silicon carbide phase 14 may also be formed between adjacent yarns 2A and 2B. As a result, the pores 10 having a relatively large pore diameter are formed in the central portion of the matrix, and the pores are deformed according to the applied stress, whereby microscopic stress dispersion is performed. .

Each of the matrices 8A and 8B is elongated, preferably linear, along the surface of the yarn, respectively, and each of the matrices 8A and 8B is orthogonal to one another. Then, the matrix 8A in the yarn arrays 1A, 1C, and 1E and the yarn array 1 orthogonal to the matrix 8A
The matrix 8B in B, 1D, and 1F is continuous at the gap between the yarns 2A and 2B, respectively. As a result, the matrices 8A and 8B form a three-dimensional lattice as a whole.

The SiC-based material phase preferably has a gradient composition in which the carbon concentration decreases as the distance from the yarn surface increases.

Here, the thickness of the matrix layer formed by impregnating the skeleton with the SiC-based material is preferably at least 0.01 mm. Further, it is preferably at least 0.05 mm, more preferably at least 0.1 mm. If the thickness of the matrix layer is less than 0.01 mm, sufficient durability cannot be provided under high oxidation conditions.

In the SiC-based composite material used in the present invention, the Si concentration in the matrix layer preferably decreases from the surface toward the inside. By giving a gradient to the Si concentration in the matrix layer, it is possible to significantly improve the corrosion resistance and strength in a strongly oxidized corrosion environment, the healing function against defects in the surface layer and the inner layer, and furthermore, the material expansion due to the difference in thermal expansion coefficient. Thermal stress deterioration can be prevented. This is because the Si concentration in the surface layer portion is relatively higher than the Si concentration in the inner layer portion, so that the generated microcracks are healed during heating and maintain oxidation resistance.

As described above, the SiC-based composite material used in the present invention has the impact resistance, high hardness, and light weight of the C / C composite, and the oxidation resistance, spalling resistance, and self-lubrication of the SiC-based material. Properties, abrasion resistance, etc.
Since it also has self-healing properties, it can withstand long-term use under high-temperature oxidation conditions.

Further, since the SiC-based composite material used in the present invention can completely remove metallic silicon, it does not elute metallic silicon to the outside and, when processed as a member, has fine pores. Due to the presence of two types of pores appearing on the surface, the surface roughness increases, and the kinetic friction coefficient is larger than that of the raw material C / C composite.
As a result, oxidation resistance and mechanical strength due to the formation of SiC as a matrix can be improved.

Further, the SiC-based composite material used in the present invention can suppress the expansion phenomenon during firing of the C / C composite in the longitudinal direction at the time of silicon carbide generation reaction. Since the dimensional accuracy can be improved, it is possible to relatively easily manufacture a large thin member that cannot be manufactured with a silicon carbide-based material.

The Si—SiC-based composite material and the SiC-based composite material used in the present invention can be preferably manufactured by the following method. That is, it acts as a matrix on the bundle of carbon fibers, and eventually contains a powdery binder that becomes free carbon with respect to the bundle of carbon fibers, such as pitch, coke, and, if necessary, a phenol resin. A carbon fiber bundle is produced by incorporating a powder or the like. As described in JP-A-2-80639, a flexible film made of a plastic such as a thermoplastic resin is formed around the carbon fiber bundle to obtain a preformed yarn as a flexible intermediate material. The formed yarn is made into a sheet-shaped preformed sheet (prepreg sheet),
After laminating the required amount, 180-2000 by hot press
° C., by molding under the conditions of atmospheric Zhuang ~500kg / cm ^2, to obtain a preform. Alternatively, the preform is carbonized at 700 to 1200 ° C. as necessary,
It is graphitized at 00 to 3000 ° C. to obtain a fired body (C / C composite).

The carbon fiber is obtained by preparing a pitch for spinning, melt-spinning, infusibilizing and carbonizing a pitch-based carbon fiber and an acrylonitrile (co) polymer fiber by using a petroleum pitch or a coal tar pitch as a raw material. Any of the obtained PAN-based carbon fibers may be used. Thermosetting resins such as phenolic resins and epoxy resins and tars and pitches are used as carbon precursors necessary for forming the matrix, and these include cokes, metals, metal compounds, inorganic and organic compounds, and the like. You may go out.

Next, the compact or fired body produced as described above and metallic silicon are held for 1 hour or more in a temperature range of 1100 to 1400 ° C. and a furnace pressure of 0.1 to 10 hPa. The holding time may vary depending on various factors. However, the generated gas such as CO due to the change of the inorganic polymer or inorganic substance into ceramics is removed from the firing atmosphere, and an external firing atmosphere such as O _{2 in the} atmosphere. It suffices if the time is long enough to prevent the contamination. At this time, 0.1 NL per 1 kg of the total weight of the molded body or the fired body and the metallic silicon is used.
(Normal liter: 1200 ° C., pressure 0.1 hPa, equivalent to 5065 liter)
It is preferable to form the SiC layer on the surface of the formed body or the fired body while flowing an inert gas of NL or more, more preferably 10 NL or more.

As described above, at the time of firing (ie, the metal silicon
Step before melting and impregnation of element) Inert gas atmosphere
To convert inorganic polymers or inorganic materials into ceramics
Generated gas such as CO due to the change of temperature from the firing atmosphere
And O in the atmosphere _TwoOf firing atmosphere from outside
By preventing contamination, metal silicon is subsequently melted and contained.
The porosity of the composite material obtained by immersion can be kept low.
it can.

Then, the temperature is raised to 1450 to 2500 ° C., preferably 1700 to 1800 ° C., and silicon is melted and impregnated into the open pores of the molded body or fired body, and Si- By forming the SiC-based material, a Si-SiC-based composite material is manufactured.
In this process, when a compact is used, the compact is fired to produce a Si-SiC-based composite material.

On the other hand, when producing a SiC-based composite material, the following steps are additionally performed. The furnace temperature is once cooled to the ambient temperature (20 ° C. to 25 ° C.), or the furnace pressure is reduced to about 1 while maintaining the furnace temperature.
Pressure to about 2000 bar
° C, preferably up to 2100 ° C-2500 ° C,
By holding for about one hour, a SiC-based composite material is manufactured from the Si-SiC-based composite material.

As described above, by the high-temperature heat treatment under normal pressure, silicon present as metallic silicon in the Si—SiC-based composite material is converted from silicon carbide that has already been generated into carbon fibers and carbon components other than carbon fibers. (Synonymous with free carbon containing partially graphitized carbon) to complete the reaction with these carbons, so that metallic silicon is completely absent and metallic silicon elutes to the outside There is no.
In addition, silicon carbide formed by the heat treatment under reduced pressure diffuses into carbon fibers and carbon components outside the carbon fibers, resulting in SiC.
The system material is formed, and at the same time, pores having a large pore size are formed inside the matrix from which silicon has escaped.

Thus, two types of pores are formed in the matrix: pores having a relatively small pore diameter generated during heat treatment under reduced pressure, and pores having a relatively large pore diameter formed by heating at normal pressure and high temperature. Will be done. That is, a SiC-based composite material having a pore size distribution of two peaks is obtained.

Here, as the Si—SiC composite material and the SiC composite material used in the present invention, a C / C composite in which a flexible intermediate material made of an organic substance is used on the outer periphery of a carbon fiber bundle is produced, and silicon is impregnated. By melting, in the molded article or fired body, the flexible intermediate material is thermally decomposed and elongated open pores remain in the gap between the yarns. Silicon can be infiltrated. During this infiltration process, the silicon reacts with the carbon of the yarn and gradually carbonizes from the yarn surface side, whereby the Si-SiC-based composite material and the SiC-based composite material used in the present invention can be produced. Note that, depending on the application, the composite material having such a configuration may be formed as a so-called composite material layer only on a part of the surface layer portion of the skeleton portion made of the C / C composite.

The depth of the composite material layer is adjusted by adjusting the open porosity and the pore size of the molded or fired body.
For example, when the thickness of the composite material layer is 0.01 to 10 mm, the open porosity at least in the vicinity of the surface of the molded or fired body is 5 to 50%, and the average pore diameter is 1 μm or more. Open porosity of molded or fired body is 10-50%
It is preferable that the average pore diameter be 10 μm or more. When the open porosity is less than 5%, the binder in the molded body or the fired body cannot be completely removed, and 50%
If it is larger, the SiC-based material will be impregnated and formed deep inside the skeleton, and the impact resistance of the composite material will be reduced.

In order to form the composite material layer only on the surface of the C / C composite, a molded body adjusted so that the open porosity at least in the vicinity of the surface becomes 0.1 to 30% during firing is used. Is preferred. That is, the thickness of the coating of the flexible intermediate material made of the thermally decomposable organic substance with respect to the carbon fiber bundle may be adjusted.

In order to reduce the open porosity of the molded body or the fired body from the surface to the inside, a plurality of preformed sheets made of preformed yarns having different binder pitches are placed from the inside to the surface layer side. It is performed by arranging and molding such that the binder pitch becomes larger toward it.

In the case where the silicon concentration in the composite material layer is provided with a gradient, the fired body adjusted so that the open porosity near the surface decreases from the surface toward the inside, or at least the open porosity near the surface A composite material is manufactured by using a molded body adjusted so that the particle size decreases from the surface toward the inside during firing. To control the porosity of the SiC-C / C composite composite to 0.5% to 5%,
When impregnating the compact or fired body with metallic silicon, it can be easily carried out by adjusting the amount of metallic silicon in accordance with the open porosity of the compact or fired body.

The above Si—SiC composite material or SiC
When manufacturing the polishing jig of the present invention using a system composite material, if the composite material manufactured as described above is cut into appropriate dimensions using a surface grinder or the like, and manufactured by polishing and finishing. Good. Also, after laminating the required amount of the preformed sheet, it is formed into a desired shape (preformed body) by hot pressing, and this is fired or, without firing, the metal silicon and the composite material used in the present invention. Can also be produced by forming a matrix by the production method described above.

[0058]

EXAMPLES Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. C / C composite used in each example, Si
A method for producing a SiC-based composite material and a SiC-based composite material will be described below.

(Production method of C / C composite) A prepreg sheet impregnated with a phenol resin is prepared by laminating carbon fibers in one direction so that the carbon fibers are orthogonal to each other. / Cm ²
To cure the resin. Next, the mixture was fired at 2000 ° C. in nitrogen to produce a C / C composite. The density of the obtained C / C composite was 1.0 g / cm ³ ,
The open porosity was 50%.

(Method for Producing Si-SiC Composite Material) The above C / C composite was prepared from a sufficient amount of porosity of 5%, having a purity of 99.8% and an average particle size of 1 mm.
After contacting with the powder, the temperature in the firing furnace was maintained at 1300 ° C., the flow rate of argon gas as an inert gas was 20 NL / min, and the internal pressure of the firing furnace was maintained at 1 hPa for 4 hours, while maintaining the pressure in the firing furnace as it was, By raising the furnace temperature to 1600 ° C., the C / C composite was impregnated with Si,
A Si-SiC-based composite material was manufactured.

(Method for producing SiC-based composite material)
The C composite was brought into contact with Si powder having a purity of 99.8% and an average particle size of 1 mm, which was sufficient to have a porosity of 5%, the temperature in the firing furnace was 1300 ° C, and argon was used as an inert gas. Gas flow rate 20NL / min, firing furnace internal pressure 1
After maintaining the pressure in the firing furnace at hPa for 4 hours, the temperature in the furnace was raised to 1600 ° C. while maintaining the pressure in the firing furnace, so that the C / C composite was impregnated with Si. Furthermore,
While maintaining the furnace temperature as it is, the furnace pressure was increased to about 1 atm.
By raising the furnace temperature to 2200 ° C. and holding for 1 hour, the metal silicon which may remain in some cases and the silicon carbide which has already been generated are removed from the carbon fiber and the carbon component outside the carbon fiber (1). (Which is synonymous with free carbon containing partially graphitized carbon) and reacted with these carbons to produce a SiC-based composite material.

(Examples 1 and 2, Comparative Example) From the Si-SiC-based composite material and the SiC-based composite material manufactured as described above, a diameter: 400 ± 0.2 mm and a thickness: 13 by a surface grinder. After cutting to ± 0.2mm, 8
With a 00 # whetstone, flatness: 0.01 mm or less, flatness (R
max): Polishing was performed so as to be 3 μm or less, thereby preparing a surface plate as a polishing jig (Examples 1 and 2). For comparison, an alumina surface plate having the same shape was prepared (Comparative Example).

Next, the obtained surface plates (Example 1)
2 and Comparative Example) were applied to the polishing apparatus shown in FIG. 4, and the productivity and yield of polished silicon wafers were examined. As a result, in Examples 1 and 2, not only could cracks generated during handling be prevented, but also the weight could be reduced to １ ／ or less, as compared with Comparative Examples. Further, Examples 1 and 2 were compared with Comparative Examples,
Since there is almost no need to replace the polishing jig due to damage, the productivity and yield of the polished silicon wafer can be improved.

[0064]

As is clear from the above description, the polishing jig of the present invention not only maintains the dimensional accuracy and compressive strength required for polishing for a long period of time, but also is lightweight, so Productivity and yield can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a yarn aggregate that is a skeleton of a composite material used in the present invention.

FIG. 2 shows an example of the structure of a Si—SiC-based composite material used in the present invention.
FIG. 2B is a cross-sectional view taken along line a-IIa, and FIG. 2B is a cross-sectional view taken along line IIb-IIb in FIG. 1.

FIG. 3 shows an example of the structure of a SiC-based composite material used in the present invention, and (a) shows IIa-I in FIG.
FIG. 2B is a cross-sectional view taken along line Ia, and FIG. 2B is a cross-sectional view taken along line IIb-IIb in FIG. 1.

FIG. 4 is an explanatory view showing an example of a polishing apparatus.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E, 1F...
2A, 2B ... yarn, 3 ... fiber bundle (yarn), 4A, 4
B: Silicon carbide phase, 5A, 5B, 5C: Si-SiC-based material phase, 6: Yarn aggregate, 7: Si-SiC-based composite material, 8A: Matrix, 8B: Matrix, 9: Small projection, 10 ... Pores, 12 ... SiC-based composite material, 14 ...
Silicon carbide phase, 20 polishing machine, 21 pressure head, 22
... Mount plate, 23 ... ceramic product, 25 ... polishing cloth, 26 ... surface plate, 27 ... head rotating shaft.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (11)

[Claims] 1. A method comprising at least 55 to 75% by weight of carbon, 1 to 10% by weight of silicon, and 10 to 50% by weight of silicon carbide, wherein at least a bundle of carbon fibers and a carbon component other than carbon fibers are mixed. A yarn aggregate in which the contained yarns are three-dimensionally combined while being oriented in the layer direction, and are integrated so as not to be separated from each other, and Si-filled between adjacent yarns in the yarn aggregate. A matrix comprising a SiC-based material and having a dynamic friction coefficient of 0.05 to 0.6 and a porosity controlled to 0.5 to 10%.
-A polishing jig comprising a SiC-based composite material. 2. The matrix of claim 1, wherein said matrix comprises a silicon carbide phase formed along a surface of said yarn.
3. The jig for polishing treatment according to item 1. 3. The polishing jig according to claim 1, wherein the matrix includes a silicon phase made of silicon, and the silicon carbide phase is generated between the silicon phase and the yarn. 4. The polishing jig according to claim 1, wherein the matrix has a gradient composition in which the content ratio of silicon increases as the matrix moves away from the yarn. 5. The yarn array according to claim 1, wherein the yarn assembly includes a plurality of yarn arrays, each yarn array being formed by two-dimensionally arranging the plurality of yarns substantially in parallel. The polishing jig according to any one of claims 1 to 4, wherein the yarn aggregate is configured by stacking bodies. 6. The method according to claim 1, wherein the matrix comprises the Si—SiC.
The polishing jig according to any one of claims 1 to 5, wherein the three-dimensional network structure is formed by being continuous with each other in the composite material. 7. A polishing treatment jig made of a SiC-based composite material having a structure composed of silicon carbide, carbon fiber, and a carbon component other than carbon fiber and having a skeleton portion and a matrix formed around the skeleton portion. Wherein at least 50% of the silicon carbide is β-type, the skeleton is formed of carbon fiber and a carbon component other than carbon fiber, and silicon carbide is present in a part of the skeleton. The matrix may be formed of silicon carbide, the matrix and the skeleton may be integrally formed, and the SiC-based composite material may have a porosity of 0.5 to 5% and a double crest shape. A polishing jig having an average pore size distribution of: 8. The polishing jig according to claim 7, wherein the matrix is formed along a surface of a skeleton portion. 9. The polishing jig according to claim 7, wherein the matrix has a gradient composition in which the content ratio of silicon increases as the matrix moves away from the surface of the skeleton. 10. A yarn array produced by arranging at least a plurality of yarns composed of carbon fibers and carbon components other than carbon fibers in a two-dimensional array substantially parallel to each other,
The polishing jig according to any one of claims 7 to 9, wherein the jig is made of a yarn assembly that is manufactured by laminating a required number of layers so as to be orthogonal to each other. 11. The polishing jig according to claim 7, wherein the matrix is continuous with each other in the SiC-based composite material to form a three-dimensional network structure.