JP2013100476A - Friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction material excellent in heat resistance, wear resistance, fade resistance and strength even at high-temperature and high-load ranges.SOLUTION: The friction material contains ceramics, which is used as a matrix thereof, and a carbonaceous material. Since a base stock having high heat resistance, high toughness and high strength is used as the matrix thereof, the friction material can withstand bad influences such as pyrolysis. Even when the friction material is used in high-temperature and high-load ranges, the friction material keeps excellent heat resistance, excellent wear resistance and a high coefficient of friction.

Description

  The present invention relates to a friction material used for brake pads, brake linings, clutch facings and the like of automobiles, railway vehicles, industrial machines, and the like, and particularly relates to a friction material having excellent heat resistance and strength.

In recent years, demands for weight reduction and miniaturization of vehicle parts have been increased under the influence of environmental changes such as improvement in vehicle fuel efficiency and soaring raw materials. With regard to brake parts, the thermal and mechanical loads on the friction material are increasing as the diameter of the brake disc is reduced.
From the viewpoint of increasing the heat resistance and strength of the brake parts, for example, a ceramic composite material (Ceramic Matrix Composites (hereinafter referred to as “CMC”)) is applied to the rotor from a conventional FC (flaky graphite cast iron). The materials of the counterparts are also diversifying.
Under such circumstances, there is a demand for a friction material that is further superior in performance such as heat resistance, wear resistance, and fade resistance under high temperature and high load.

  As a conventional friction material, a non-Asbestos-Organic friction material (hereinafter referred to as “NAO material”) in which a fibrous material such as organic fiber is used as a fiber base material, and a binder and a friction adjusting material are blended therein is widely used. Are known. Patent Document 1 and Patent Document 2 describe a friction material that has improved heat resistance and fade properties by baking and carbonizing a friction material using an organic binder at a high temperature of 250 to 700 ° C. in a non-oxidizing atmosphere. Has been. Patent Document 3 describes a friction material having improved heat resistance and fade resistance by baking and carbonizing a friction material using an organic binder in an inert gas at 550 to 1300 ° C.

  On the other hand, the friction material which improved the intensity | strength and fade resistance by using a metal as a base material is proposed, and the patent document 4 describes the sintered friction material which used copper as the base material.

JP-A-5-215164 JP-A-9-111007 JP 2006-306970 A JP 2007-107067 A

However, the friction material obtained by carbonizing the organic binder described in Patent Documents 1 to 3 is thermally decomposed when used for a long time at a high temperature exceeding the manufacturing temperature during use, and has strength, wear resistance, and fade. There is a concern of causing a decline.
In addition, the friction material using a metal as a base material described in Patent Document 4 increases in weight as compared with the NAO material, and the strength decreases at a high temperature near the melting point of the metal that is the base material. There are concerns about problems such as increased wear and sticking to the mating material due to flow.
As described above, in the conventional friction material, there is room for improvement in the performance in a high temperature and high load region particularly with the CMC rotor as the counterpart material.

  The present invention solves the above-described problems, and an object thereof is to provide a friction material that is excellent in heat resistance, wear resistance, fade resistance, and strength even in a high temperature and high load region.

The present inventors have found that the above problem can be solved by using ceramics as a matrix. That is, the present invention is as follows.
[1] A friction material containing a ceramic material as a matrix and containing a carbon material.
[2] The friction material according to [1], wherein the ceramic is at least one selected from the group consisting of oxide ceramics, nitride ceramics, and carbide ceramics.
[3] The friction material according to [2], wherein the oxide ceramic is at least one of zirconia and alumina.
[4] The friction material according to [2], wherein the nitride ceramic is at least one selected from the group consisting of silicon nitride, aluminum nitride, and sialon.
[5] The friction material according to [2], wherein the carbide ceramic is at least one selected from the group consisting of silicon carbide, boron carbide, titanium carbide, and tungsten carbide.
[6] The friction material according to any one of [1] to [5], wherein the carbon material is at least one of graphite and carbon fiber.
[7] The friction material according to any one of [1] to [6], further including at least one metal selected from the group consisting of silicon, titanium, and iron.

  According to the present invention, by using a material having high heat resistance, high toughness and high strength as a matrix, the friction material is not affected by thermal decomposition or the like, and is heat resistant even when used in a high temperature and high load region. It is possible to provide a friction material that is excellent in wear resistance and wear resistance and has a high friction coefficient. Further, it is possible to provide a friction material having durability against chipping and cracking during braking.

FIG. 1 is a diagram in which the braking surface of the friction material (sintered body) prepared in Example 34 after the friction test is observed with an optical microscope. FIG. 2 is a diagram in which the braking surface of the friction material (sintered body) prepared in Example 36 after the friction test is observed with an optical microscope.

<Configuration of friction material>
The friction material of the present invention uses ceramics as a matrix. The composition of the ceramic is not particularly limited. For example, oxide ceramics, nitride ceramics, carbide ceramics, and the like can be used. As oxide ceramics, alumina, forsterite, zirconia, titania, silica, magnesia, zircon, mullite, ferrite, cordierite, steatite, barium titanate, zinc oxide, hydroxyapatite, tricalcium phosphate, fluoride And apatite. Examples of the nitride ceramics include aluminum nitride, silicon nitride, titanium nitride, boron nitride, sialon and the like. Examples of the carbide ceramics include silicon carbide, boron carbide, titanium carbide, tungsten carbide and the like. Of these, zirconia, which is an oxide ceramic, and silicon nitride, which is a nitride ceramic, are preferable from the viewpoint of high mechanical strength and toughness. The zirconia is preferably stabilized, for example, yttria (Y ₂ O ₃ ) stabilized zirconia or calcia (CaO) stabilized zirconia is particularly preferable. The average particle diameter of the primary particles of zirconia is preferably 100 nm or less from the viewpoint of sinterability.

  The ceramics may be a single composition or a mixed composition of two or more. As a mixed composition, for example, when zirconia is used as a base material, it is preferable to use alumina together. In this case, the content of alumina is preferably 5 to 25% by volume in the entire friction material. By containing alumina in such a range, the sinterability of the friction material is improved and densified, and chipping and cracking during braking can be suppressed.

Furthermore, it is preferable to add a sintering aid as required. In particular, when silicon nitride is used as a base material, it is preferable to add it because the sinterability can be improved. The sintering aid used in the present invention is not particularly limited, and any one can be used as long as it is used as a normal sintering aid, such as Y ₂ O ₃ , _{MgO, ZrO 2, ZrO 2,} Al 2 O 3, HfO 2 , and the like. The content of the sintering aid is preferably 1 to 15% by weight in the entire friction material.

The friction material of the present invention further contains a carbon material. A friction material made only of a ceramic matrix has high strength and a high friction coefficient, but on the other hand, since the shear stress at the friction interface increases, wear of the friction material increases and the friction coefficient may become unstable. By blending the carbon material, the wear resistance of the friction material is improved, and chipping and cracking during braking can be suppressed. Examples of the carbon material include fullerene, carbon nanotube, carbon fiber, graphite, amorphous carbon, activated carbon, and coke. Among these, graphite and carbon fiber are preferable.
As graphite, artificial graphite, natural graphite (flaky graphite, massive graphite, earthy graphite, elastic graphite, expanded graphite) and the like can be used. The average particle diameter of graphite is preferably 10 to 1000 μm as measured by a laser diffraction particle size distribution method or a sieving method (median diameter). If it is this range, sinterability does not fall and it can suppress the chipping and cracking at the time of braking.
The carbon fiber preferably has an average fiber length of 0.1 to 6.0 mm, more preferably 0.1 to 3.0 mm. If the average fiber length is within this range, the carbon fiber pulling effect is great, the friction material is hardly chipped, and the strength is maintained. Moreover, it is preferable that an average diameter is 5-20 micrometers. Carbon fibers having the above fiber length may be blended at the raw material stage, or may be adjusted to be within the above range by appropriately setting the mixing conditions and the like at the blending stage. In addition, it is preferable from the viewpoint of dispersibility that the carbon fiber is used in a state of being fibrillated into a single fiber rather than a bundle.
In addition, the said carbon material may be used independently or may use 2 or more types together.
The carbon material does not include carbide-based ceramics.

The content of the carbon material in the entire friction material is preferably 40% by volume or less, more preferably 30% by volume or less, and more preferably 2 to 20% by volume. Within such a range, the wear resistance can be improved.
Moreover, when using graphite as a carbon material, there exists a possibility that the sinterability of ceramics may fall while there exists a tendency for abrasion resistance to improve, so that there is much content. Therefore, when the friction material is produced by pressureless sintering, the graphite content is limited due to a decrease in the sintered density, and 2 to 5% by volume is preferable. On the other hand, in the case of producing by pressure sintering, a high-density sintered body is obtained, so the graphite content can be made 2 to 30% by volume, and there is no concern about deterioration of sinterability. Abrasion can be further improved.

The friction material of the present invention may further contain a metal (powder) such as silicon, titanium, iron and nickel, and preferably contains one or more metals selected from the group consisting of silicon, titanium and iron. By containing a metal, it is effective in improving wear resistance by imparting lubricity to the friction material. As the metal to be added, silicon and titanium are particularly preferable from the viewpoints of a large effect of improving wear resistance and a high melting point and low environmental load. These metals are added alone and are distinguished from metal compounds such as silicon carbide, titanium carbide, and silicon nitride as ceramic materials.
The metal content in the friction material is preferably 1 to 5% by volume. Within such a range, the friction coefficient and the friction material strength can be maintained well while improving the wear resistance.
In addition, when metal is added, wear resistance can be improved, but there is a concern that the sinterability of ceramics may be reduced. Therefore, it is preferable to achieve densification by pressure sintering.

The friction material of the present invention includes metal fibers such as steel fibers, silicon carbide fibers, Al ₂ O ₃ —SiO ₂ ceramic fibers, and biosoluble inorganic fibers as blending components other than the above as long as the effects of the present invention are not impaired. Fiber base materials such as inorganic fibers such as barium sulfate, calcium fluoride, titanium carbide, titanium nitride, vermiculite, mica and other inorganic compounds, alumina, magnesia, zirconia, titania, iron oxide, tin oxide and other metal oxides, nitriding You may contain friction modifiers, such as solid lubricants, such as boron and aluminum nitride.

The friction material of the present invention composed of the above components preferably has a density of 60% or more, and more preferably 80% or more. If the density is within the range, the bonding force between the ceramics is strengthened, and a friction material excellent in wear resistance and suppression of chipping and cracking during braking can be obtained. Here, the density is a relative density calculated from the following formula.
(Sintered body density / theoretical density) × 100 = relative density (%)
In order to make a density into the said range, methods, such as raising sintering temperature or pressure sintering, are mentioned, for example.

<Friction material manufacturing method>
The friction material of the present invention includes a step of adjusting a raw material powder by mixing a predetermined amount of metal / inorganic compound powder, a carbon material, and an arbitrary blending component, which are raw materials for the ceramic, a molding step, and a sintering step. It can be obtained through a process.

The step of preparing the raw material powder includes, for example, mixing a metal / inorganic compound powder, which is a raw material for ceramics, a carbon material, and a compounding component in a dispersion medium such as ethanol by a ball mill for a predetermined time, followed by drying and dispersing. It is preferable to sequentially include a step of removing the medium and sizing using a sieve having a sieve having a size of 100 to 500 μm.
In addition, as a method of mixing the metal / inorganic compound powder as the raw material of the ceramic, the carbon material, and the blending component, dry mixing may be performed for a predetermined time by a sample mill without using a dispersion medium.
In addition, the order in which each material is mixed is not particularly limited, and all materials may be mixed at one time. After mixing and sizing the ceramic raw material and the carbon material, optional components such as metal and fiber base material are added. You may mix and granulate.

In the forming step and the sintering step, known ceramic forming methods and sintering methods are appropriately used.
Examples of the molding method include dry molding methods such as uniaxial pressure molding and CIP molding (cold isostatic pressing).
Uniaxial pressure molding is a method of obtaining a compact by uniaxially pressing a powder formulation in a mold. CIP molding is a method of obtaining a molded body by putting a powder preparation such as granules or a preformed body that has been formed into a predetermined shape in advance into a rubber container and pressurizing it with hydrostatic pressure. . This method applies pressure evenly from the surroundings, and is suitable for the production of a more uniform molded body than uniaxial pressure molding.
As the molding method, in addition to the dry molding method described above, plastic molding methods such as injection molding and extrusion molding; casting molding methods such as mud casting, pressure casting and rotary casting; tape molding methods such as a doctor blade method and the like can be applied.
The above molding methods may be used alone or in combination of two or more.

  Examples of the sintering method include an atmosphere sintering method, a reaction sintering method, a normal pressure sintering method, a thermal plasma sintering method, and the like. In addition, the sintering temperature and the holding time at the sintering temperature can be appropriately set according to the type of ceramic, and usually 1000 to 2000 ° C. and 2 to 6 hours are preferable. For example, in the case of zirconia, 1000 to 1800 ° C. and 2 to 4 hours are preferable.

  It is also possible to perform sintering while applying pressure. As such a method, pressure sintering methods such as HP (hot press), HIP molding (hot isostatic pressing), and discharge plasma sintering are applied. You can also. HP is a method of performing sintering while uniaxial pressure forming. HIP molding is a method in which sintering is performed while being pressurized with hydrostatic pressure. The pressure sintering method is preferable in that the resulting sintered body has a high density as described above, and as a result, the blending amount of graphite imparting wear resistance can be increased. The holding time at the sintering pressure, the sintering temperature and the sintering temperature can be appropriately set according to the type of ceramic, and is usually preferably 10 to 400 MPa, 1000 to 2000 ° C., and 0.5 to 6 hours. For example, in the case of zirconia, 10 to 200 MPa, 1000 to 1800 ° C., more preferably 1000 to 1400 ° C., and 0.5 to 4 hours are preferable.

  Sintering may be performed in the atmosphere or in an inert gas such as nitrogen gas or argon gas depending on the type of ceramic or the material to be added, or carbon monoxide gas, hydrogen gas, etc. You may carry out in reducing gas. Moreover, you may carry out in a vacuum.

  The sintered compact obtained through the above steps is subjected to treatments such as cutting, grinding, and polishing as necessary to produce the friction material of the present invention.

  The friction material according to the present invention can be applied to either a dry friction material or a wet friction material.

  The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.

<Examples 1-3, Comparative Example 1 (pressureless sintering)>
The materials used are shown below.
Yttria stabilized zirconia: TZ-3Y-E manufactured by Tosoh Corporation
Scale-like graphite: CB-150 (average particle size 40 μm) manufactured by Nippon Graphite Co., Ltd.
Easily sinterable alumina: TM-DAR (average particle size 0.1 μm) manufactured by Daimei Chemical Co., Ltd.

Example 1
347 g of 3 mol% yttria-stabilized zirconia and 2 g of scaly graphite were ball-milled in an ethanol solvent at a rotation speed of 100 rpm for 24 hours, dried, and sized using a 200 μm sieve to obtain raw material powder. After 150 g of raw material powder was uniaxially molded at 20 MPa, CIP molding was performed at 245 MPa and sintered at 1400 ° C. for 2 hours in argon to obtain a sintered body.

Example 2
A sintered body was obtained in the same manner as in Example 1 except that 338 g of 3 mol% yttria-stabilized zirconia and 12 g of flaky graphite were used.

Example 3
A sintered body was obtained in the same manner as in Example 1 except that 285 g of 3 mol% yttria-stabilized zirconia, 7 g of flake graphite, and 58 g of easily sinterable alumina were used.

Comparative Example 1
150 g of 3 mol% yttria-stabilized zirconia was uniaxially molded at 20 MPa, then CIP-molded at 245 MPa, and sintered in argon at 1400 ° C. for 2 hours to obtain a sintered body.

<Physical property evaluation>
1) Relative density (%)
The relative density was determined by (sintered body density / theoretical density) × 100.
The sintered body density was calculated from the weight and volume of the obtained sintered body, and the theoretical density was calculated from the true density and mixing ratio of the raw materials.
2) Bending test A test piece (3 × 4 × 40 mm) was prepared from the sintered body, and the test was performed in accordance with JIS R 1601.

<Friction test>
A test piece (13 × 15 × 35 mm) was prepared from the sintered body, and the following friction test was performed using a friction analyzer friction tester manufactured by Sakai Engineering Co., Ltd.
Opposite material: CMC rotor made of SGL carbon Initial speed: 50 km / h
Deceleration: 0.3G
Braking temperature: 100 ° C
Number of brakings: 200 Evaluation items: Average friction coefficient, pad wear amount, rotor wear amount, presence / absence of chipping / cracking during braking (1: specimen breakage, 2: cracking at the center of the specimen, 3: chipping at the end of the specimen) Large: 4: Small chip at the end of the test piece, 5: No chipping)

  The evaluation results are shown in Table 1.

  From Table 1, it can be seen that all of the test pieces of the examples are good in the strength and friction test. Further, in Examples 1 and 2 in which scaly graphite was blended, the pad wear amount and the rotor wear amount were reduced. Furthermore, Example 3 using both alumina and graphite was particularly effective, and the relative density increased due to the improvement in sinterability.

<Examples 4 to 20, Comparative Example 2 (Pressure Sintering)>
The materials used are shown below.
Yttria stabilized zirconia: TZ-3Y-E manufactured by Tosoh Corporation
Scale graphite: CB-150 (average particle size 40 μm) manufactured by Nippon Graphite Industries Co., Ltd.
Artificial graphite A: EG-1 (average particle size 40 μm) manufactured by Shin Nippon Techno Carbon Co., Ltd.
Artificial graphite B: Tokai Carbon Co., Ltd. G-152A (average particle size 500 μm)
Elastic graphite: Superior Graphite Co. RGC14A (average particle size 250 μm)
Carbon fiber: PAN fiber (3mm chop product) manufactured by Toho Tenax Co., Ltd.

  A mixture of the above materials in the ratio shown in Table 2 was ball mill mixed in an ethanol solvent at a rotation speed of 100 rpm for 24 hours, dried, and then sized using a 200 μm sieve to obtain a raw material powder. The raw material powder was hot press-molded in argon under a sintering surface pressure of 20 MPa, a sintering temperature of 1300 ° C., 1150 ° C. or 1100 ° C., and a holding time of 2 hours, and then a sintered body was obtained.

  About each sintered compact, the physical-property evaluation and the friction test were done like Example 1. FIG. The results are shown in Table 2. In addition, the average fiber length of the carbon fibers in each of the sintered bodies of Examples 15, 16, 19, and 20 was confirmed to be 0.1 mm from the average value of 30 by observing the mixed state with an optical microscope. .

From Table 2, it can be seen that all the test pieces of the examples are good in the strength and friction test. From the comparison between Comparative Example 2 and Examples 4 to 8, it was confirmed that the amount of pad wear and the amount of rotor wear was reduced by adding scaly graphite, and further the effect of suppressing frictional material chipping during braking was confirmed. In addition, Examples 4 to 8 show that the amount of scaly graphite is preferably 20 to 30% by volume, so that the wear amount is minimized and preferable.
In Examples 9 to 16, 19 and 20, another type of graphite or carbon fiber was used as the carbon material. From these results, both artificial graphite and elastic graphite showed frictional characteristics similar to those when flaky graphite of the same degree was blended. From this, it can be seen that the effects on the physical properties and friction characteristics can be obtained almost equally regardless of the shape of graphite. In the case of carbon fiber, improvement in wear resistance was confirmed by blending.
From the comparison of Examples 7, 17 and 18 and the comparison of Examples 15, 19 and 20, if the sintering temperature is 1150 to 1300 ° C. (relative density of 80% or more), the friction coefficient and the wear amount are good. It became a result. On the other hand, when the sintering temperature is low (relative density is lower than 80%) as in Example 18 and Example 20, the amount of wear increases. This shows that the sintering temperature is preferably 1150 ° C. or higher (relative density of 80% or higher).

<Examples 21 to 26 (metal addition, pressure sintering)>
The materials used are shown below.
Yttria stabilized zirconia: TZ-3Y-E manufactured by Tosoh Corporation
Carbon fiber: PAN fiber (3mm chop product) manufactured by Toho Tenax Co., Ltd.
Titanium: manufactured by Kojundo Chemical Laboratory, Inc., particle size 45 μm pass Silicon: manufactured by Kojundo Chemical Laboratory Co., Ltd., particle size 5 μm

  Of the above materials, zirconia and carbon fiber blended in the ratios shown in Table 3 were mixed in a ball mill for 60 minutes at a rotational speed of 400 rpm in an ethanol solvent, dried, and then sized using a 200 μm sieve. Here, titanium or silicon further blended at a ratio shown in Table 3 was ball mill mixed in an ethanol solvent at a rotation speed of 100 rpm for 24 hours, dried and then sized using a 200 μm sieve to obtain a raw material powder. . The raw material powder was hot press-molded in argon under conditions of a sintering surface pressure of 20 MPa, a sintering temperature of 1300 ° C., and a holding time of 2 hours to obtain a sintered body.

  About each sintered compact, the physical-property evaluation and the friction test were done like Example 1. FIG. The results are shown in Table 3. In addition, the average fiber length of carbon fiber confirmed that it was 0.1 mm from the average value of 30 pieces, observing the mixed state with the optical microscope.

  Compared with Example 15 in which zirconia and carbon fiber had the same composition and no metal was blended, the friction materials of Examples 21 to 23 in which titanium was blended and Examples 24 to 26 in which silicon was blended had reduced pad wear. . Further, when comparing the relationship between the amount of metal blended and the amount of pad wear, there was not much change with silicon, but with titanium, the amount of pad wear could be reduced as the amount blended increased.

<Examples 27 to 32, Comparative Example 3 (Pressure Sintering)>
The materials used are shown below.
Silicon nitride: SN-9FWS (average particle size 0.7 μm) manufactured by Denki Kagaku Kogyo Co., Ltd.
Alumina (sintering aid): TM-DAR (average particle size 0.1 μm) manufactured by Daimei Chemical Co., Ltd.
Yttria (sintering aid): NanoTek Y203 (average particle size 29 nm) manufactured by CI Kasei Co., Ltd.
Scale graphite: CB-150 (average particle size 40 μm) manufactured by Nippon Graphite Industries Co., Ltd.
Carbon fiber: PAN fiber (3mm chop product) manufactured by Toho Tenax Co., Ltd.

  A material blended in the ratio shown in Table 4 was mixed in a ball mill for 24 hours in an ethanol solvent at a rotation speed of 100 rpm, dried, and then sized using a 200 μm sieve to obtain a raw material powder. The raw material powder was hot press molded in nitrogen gas under the conditions of a sintering surface pressure of 20 MPa, a sintering temperature of 1600 ° C., and a holding time of 2 hours, and then a sintered body was obtained.

  About each sintered compact, the physical-property evaluation and the friction test were done like Example 1. FIG. The results are shown in Table 4.

  The friction material of Comparative Example 3 that does not contain a carbon material has a remarkably large rotor wear amount and very high rotor attack. However, the rotor can be obtained by blending carbon fiber or graphite as in the friction materials of Examples 27 to 32. It can be seen that the aggression is greatly improved. In Examples 29, 30 and 32 containing 10% by volume or more of a carbon material, the rotor was hardly worn and the rotor aggression was very low.

<Examples 33 to 36 (carbon fiber, pressure sintering)>
Friction materials were produced by changing the fiber length and fiber state of the carbon fiber. The materials used are shown below.
Yttria stabilized zirconia: TZ-3Y-E manufactured by Tosoh Corporation
Carbon fiber: PAN fiber (3 mm chopped product (Examples 33, 34, 36) or 6 mm chopped product (Example 35)) manufactured by Toho Tenax Co., Ltd.

The above materials were blended at the ratio shown in Table 5 and sample milled under the conditions shown in Table 5 to obtain raw material powder. The raw material powder was hot press molded in argon at a sintering surface pressure of 20 MPa at 1300 ° C. for 2 hours, and then a sintered body was obtained.
The average fiber length of the carbon fibers was observed from the mixed state with an optical microscope, calculated from the average value of 30 fibers, and shown in Table 5. The state of the fiber was confirmed by observing the mixed state with an optical microscope. FIG. 1 is a diagram of the friction material (sintered body) prepared in Example 34 in FIG. 1 and the friction material (sintered body) prepared in Example 36 in FIG. Each is shown. In FIG. 1, the carbon fiber was disassembled, and in FIG. 2, the bundle was observed.

  From Table 5, all the examples showed good results in the friction test. From the comparison of Examples 33 to 35, it can be seen that the longer the average fiber length of the carbon fibers, the greater the bending strength. Further, compared with Examples 34 and 36, the strength of the friction material is higher in the defibrated state of the carbon fiber than in the bundle state, and the result of the wear test is also good. This is because the fiber is more easily disassembled when it is defibrated, and it can exist in a state where the fiber is buried in the friction material, so it is difficult to detach, and the lubrication of the fiber is effectively expressed and the amount of wear is reduced. It is thought that this is effective.

  The friction material of the present invention has excellent heat resistance and strength even in a high temperature / high load region, and is preferably used for disk pads, brake linings, clutch facings, etc. for automobiles, railway vehicles, and various industrial machines. Can do.

Claims (7)

  A friction material containing a ceramic material as a matrix and containing a carbon material.   The friction material according to claim 1, wherein the ceramic is at least one selected from the group consisting of oxide ceramics, nitride ceramics, and carbide ceramics.   The friction material according to claim 2, wherein the oxide ceramic is at least one of zirconia and alumina.   The friction material according to claim 2, wherein the nitride-based ceramic is at least one selected from the group consisting of silicon nitride, aluminum nitride, and sialon.   The friction material according to claim 2, wherein the carbide ceramic is at least one selected from the group consisting of silicon carbide, boron carbide, titanium carbide, and tungsten carbide.   The friction material according to any one of claims 1 to 5, wherein the carbon material is at least one of graphite and carbon fiber.   The friction material according to any one of claims 1 to 6, further comprising at least one metal selected from the group consisting of silicon, titanium, and iron.