JP2015174784A - Manufacturing method of carbon fiber/carbon composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a C/C composite material that can reduce temperature dependence of a friction coefficient.SOLUTION: A carbon fiber material 1 is passed through an immersion tank 4 filled with a phenolic resin solution 2, which is a carbon precursor resin solution with glass fiber 3 dispersed therein and thus the phenolic resin solution 2 with glass fiber dispersed therein is adhered to the carbon fiber 1. The carbon fiber 1 is then wound by a bobbin 51 of a winding device 5 to form a laminate. A C/C composite material is manufactured by curing the phenolic resin in the laminate to obtain CFRP and then burning the CFRP to carbonize the phenolic resin.

Description

  The present invention relates to a method for producing a carbon fiber carbon composite material.

The carbon fiber carbon composite material (hereinafter referred to as “C / C composite material”) is a composite material in which the reinforcing fibers are carbon fibers and the matrix is carbon.
This C / C composite material is expected to be a material that compensates for the weakness of FRP because it has high specific strength, high specific modulus, excellent heat resistance, and has high strength even under high temperatures of 2000 ° C or higher in an inert atmosphere. (See Non-Patent Documents 1 to 4).

On the other hand, a resin impregnation method is a general method for producing a C / C composite material.
In the resin impregnation method, carbon fiber is impregnated with a thermosetting resin liquid that becomes carbon precursor resin (resin that is carbonized by baking to form carbon), and then the carbon precursor resin is thermoset. After obtaining a carbon fiber reinforced resin (hereinafter referred to as “CFRP”), this CFRP is baked to carbonize the carbon precursor resin.

In addition, C / C composite materials have advantages such as lighter weight and better friction / braking characteristics than metals, so these characteristics can be used to make high-speed, high-load friction materials such as disc brakes for aircraft and formula cars. It is expected to be applied to various fields in the future.
However, the C / C composite material has a problem that the temperature dependence of the friction coefficient is large and the friction coefficient is particularly low at low temperatures (Non-Patent Document 5). Therefore, when using a C / C composite material as a friction material, there is a limit to the operating temperature.

Various methods have been considered to solve this problem. As one of them, the inventor of the present invention has previously studied a method of generating carbon nanotubes (CNT) on the surface of a C / C composite material using a thermal CVD method (Non-patent Document 6).
According to this method, the friction coefficient at low temperature is improved. However, when CNTs are generated on the surface, the CNTs on the surface are worn away with wear, and the friction coefficient is reduced accordingly, and the temperature dependence of the friction coefficient. It has been found that sex cannot be completely eliminated.
Accordingly, a new friction coefficient stabilization method that does not involve these problems is desired.

On the other hand, silicon carbide (SiC) generally has excellent properties such as high strength and wear resistance, so it can be used as a sliding material to replace metals and polymer materials, especially in extreme conditions such as ultra-low temperature, ultra-high temperature, and ultra-vacuum. Is an expected material. Further, SiC has oxidation resistance, and research is being conducted as a material that compensates for deterioration of mechanical properties due to oxidation of C / C composite materials (Non-Patent Documents 7 to 13).
Moreover, in the conventional C / C composite material, the friction coefficient is high when used in a high temperature range and the friction coefficient is low when used in a low temperature range. Since the friction surface is reduced and the contact area is reduced, the friction coefficient is reduced, and in high temperatures, the carbon friction powder is oxidized to become small, and the friction surface becomes a dense surface state with small friction powder. It has been clarified by past research (Non-Patent Document 14) that the friction coefficient is high.

Shunsuke Yamaji, Shinichi Baba, Masahiro Ishihara, Air Oxidation Behavior of Two-Dimensional Carbon Fiber Reinforced Carbon Composites -Effects on Thermal Expansion Tension-, Proc. -146 Kazumi Murakami, Yoshihiko Kunieda, Hideyuki Kanematsu, Takeo Oki, X-ray diffraction and cyclic voltammogram characteristics of PAN-based C / C composite surfaces with different heat treatment temperatures, Surface technology, Vol. 47, 1996, No.7, pp.633- 637 Naotaka Yunaga, Toshiya Setaka, Yuji Ushijima, C / C Composite, TANSO, Vol. 2009, 2009, No. 239, pp.184-194 Toshiaki Kaneda, Shinichi Sakaguchi, Teruto Kanaya, Research on carbon fiber reinforced carbon composite (C / C composite) cutting, Japan Society of Mechanical Engineers (C), 65, 635, 1999, pp.352-357 Haytam Kasem, SylvieBonnamy, YvesBerthier, Pascale Jacquemard, Characterization of surface grooves and scratches induced by friction of C / C composites at low and high temperatures, Tribology International, Volume 43, Issues 11, November 2010, pp.1951-1959 Kotake, Kiyotaka, Takeuchi, Yasunori, Okubo, Kazuya, Fujii, Toru, “Improvement of mechanical properties of C / C composites by adding carbonized MFC to carbon precursor resin”, Doshisha University Science and Engineering Research Report, 51 (3) (2010), pp.26-31 Shuichi Ishizawa, Takashi Machida, Effect of oxidation wear on high temperature strength of C / C composites, Transactions of the Japan Society of Mechanical Engineers (A), 63, 608, pp.189-194 Tetsuya Tashiro, Junsuke Fujiwara, Yasuhiro Takenaka, Grinding of C / C-SiC composites, Journal of the Japan Society for Abrasive Technology, Vol.51 (2007), No.7, pp.428-433 Yukio Mugo, Hiroshi Hatta, Akimitsu Okura, Yasuhiro Goto, Yutaka Sawada, Yoshihiro Kiyomiya, Toshio Sugai, SiC coating on C / C composites by simple method and evaluation of oxidation resistance, Journal of the Japan Institute of Metals, Vol. 62, No. 2 ( 1998), pp.197-206 Eiji Tani, Kazuhisa Tsuji, Fabrication of carbon fiber reinforced SiC / C composite by reactive sintering, Journal of the Ceramic Society of Japan, 105 [8] (1997), pp.703-706 Michita Too, Hiroshi Sasaki, Seiichiro Hironaka, Friction and wear properties of carbon / silicon carbide composites, Journal of the Ceramic Society of Japan, 108 [2] (2000), pp.191-195 Hayashi Hayashi, Okazaki Shuji, Hashimoto Masaaki, Yamamoto Yuji, Effects of Atmosphere and Combination on Friction Wear of SiC, Ti and TiC, Transactions of the Japan Society of Mechanical Engineers (C), Vol. 64, 627 (1998), pp.300-307 Xuan Zhou, Dongmei Zhu, Qiao Xie, Fa Luo, Wancheng Zhou, Friction and wear properties of C / C-SiC braking composites, Ceramics International, Volume 38, Issue 3, April 2012, pp.2467-2473 Christopher Byrne, Zhiyuan Wang, Influence of thermal properties on friction performance of carbon composites, Carbon 39 (2001), pp.1789-1801

  In view of the above circumstances, an object of the present invention is to provide a method for producing a C / C composite material in which the temperature dependence of the friction coefficient can be reduced.

  In order to achieve the above object, a method for producing a C / C composite material according to the present invention includes carbonizing a carbon fiber reinforced resin obtained by firing a carbon fiber reinforced resin in which a carbon fiber material is hardened with a carbon precursor resin. A method for producing a carbon fiber-carbon composite material comprising a step, wherein glass fibers are dispersed and blended in the carbon fiber reinforced resin.

  The method for producing a C / C composite material according to the present invention is not particularly limited as long as glass fibers can be dispersed and blended in CFRP as described above. For example, glass fiber dispersion in which glass fibers are dispersed in a carbon precursor resin solution After laminating the step of adhering the liquid to the carbon fiber and the adhering body to which the glass fiber dispersion is adhered, the carbon precursor resin can be cured to obtain CFRP.

  The method for adhering the glass fiber dispersion to the carbon fiber material is not particularly limited. For example, the method of adhering the glass fiber dispersion to the carbon fiber by immersing the carbon fiber material in the glass fiber dispersion tank, the carbon fiber Examples include a method of spraying and adhering a glass fiber dispersion, a method of attaching using a roll coater method, etc., and a method of adhering a glass fiber dispersion to a carbon fiber by immersing the carbon fiber in a glass fiber dispersion tank. Is preferred.

In addition, when the carbon fiber material is a long carbon fiber material, the carbon fiber material is continuously immersed in the glass fiber dispersion tank or sprayed with the glass fiber dispersion liquid while the carbon fiber material is being wound up by a winder or the like. Can be.
And it can laminate | stack to predetermined | prescribed thickness (thickness according to C / C composite material to obtain), winding up by the winder side.

In the case of a short mat-like carbon fiber material, the glass fiber dispersion may be attached in a batch manner.
And also in the case of a short mat-like carbon fiber material, it can be laminated | stacked by predetermined | prescribed thickness (thickness according to the C / C composite material to obtain).
The laminated body laminated as described above may be cured in a state where the carbon precursor resin is made into a semi-cured state if necessary, and then the semi-cured body is put into a mold and molded into a predetermined shape. it can.

In the method for producing a C / C composite material according to the present invention, the carbon fiber material is not particularly limited, and examples thereof include monofilament, chopped strand, chopped strand mat, roving, roving cloth, and glass yarn.
Further, the carbon fiber may be either a PAN-based carbon fiber or a pitch-based carbon fiber, but a PAN-based carbon fiber is preferable.

  The carbon precursor resin is not particularly limited as long as carbon serving as a matrix can be formed by firing, and examples thereof include thermosetting resins and thermoplastic resins such as phenol resins and epoxy resins, and phenol resins are preferable. .

  As glass fiber, if it can be dispersed uniformly and uniformly in the carbon precursor resin liquid, it can adhere well to the carbon fiber together with the carbon precursor resin liquid, and can enter between the carbon fibers of the CFRP, Although not particularly limited, chopped glass fibers having a fiber length of 8 to 10 mm and a fiber diameter of 15 to 19 μm are suitable.

The firing conditions of CFRP are not particularly limited as long as the carbon precursor resin can be carbonized and Si constituting the glass fiber reacts with carbon to become SiC, but the low temperature firing step, the intermediate temperature firing step, and the high temperature firing step are not limited. Preferably it is done in stages.
And although it does not specifically limit, It is preferable to perform a low temperature baking process at 900-1100 degreeC, a medium temperature baking process at 1300-1500 degreeC, and a high temperature baking process at 2000-2400 degreeC.

The firing of CFRP is not particularly limited as long as the carbon precursor resin can be carbonized well, but is preferably performed in an inert gas atmosphere.
Although it does not specifically limit as an inert gas, Argon, helium, nitrogen, etc. are mentioned.

As described above, the production method of the present invention is a production of a carbon fiber carbon composite material comprising a step of firing a carbon fiber reinforced resin in which a carbon fiber material is solidified by a carbon precursor resin to carbonize the carbon precursor resin. Since the glass fiber is dispersed and blended in the carbon fiber reinforced resin, a part of carbon formed by carbonization of the carbon precursor resin or the carbon fiber material is used in the firing step. Part of the carbon that constitutes reacts with the Si element that constitutes the glass fiber, and the glass fiber-derived SiC is dispersed in the C / C composite material.
And it is thought that the temperature dependence of a friction coefficient is reduced by this dispersed SiC. That is, the so-called “scratch effect” by SiC is exhibited on the friction surface, and a stable friction coefficient can be obtained not only in the high temperature range but also in the low temperature range.

It is one Embodiment of the manufacturing method of the C / C composite material of this invention, Comprising: It is a figure explaining the outline of the manufacturing process of the CFRP. 6 is a graph showing the X-ray diffraction data of the C / C composite material specimens obtained in Example 1 and Comparative Example 3 in comparison. It is a figure explaining the friction testing machine used in order to measure the temperature dependence of a friction coefficient. It is a graph showing the temperature dependence of the friction coefficient of the C / C composite material specimens obtained in Example 1 and Comparative Examples 1 and 2, respectively. It is a copy of the photograph imaged with the scanning electron microscope of the state of a friction surface after rubbing the C / C composite-material test pieces obtained in Example 1, Comprising: The figure (a) is made to rub at normal temperature. Fig. 4 (b) shows the case of friction at 300 ° C. It is a copy of the photograph imaged with the scanning electron microscope of the state of a friction surface after rubbing the C / C composite-material test pieces obtained in the comparative example 1, Comprising: The figure (a) is made to rub at normal temperature. Fig. 4 (b) shows the case of friction at 300 ° C.

Below, an example of the manufacturing method of the C / C composite material concerning this invention is demonstrated in detail.
As shown in FIG. 1, the C / C composite material is produced by passing the carbon fiber material 1 through an immersion tank 4 filled with a phenol resin liquid 2 which is a carbonized precursor resin in which glass fibers 3 are dispersed. The carbon fiber material 1 is continuously wound around the bobbin 51 of the winding device 5 in a state where the glass fiber is adhered to the carbon fiber material 1 together with the resin liquid to form the cylindrical laminate 6 having a predetermined thickness and width.
The laminated thickness and the length in the cylinder axis direction are appropriately determined according to the size and thickness of the C / C composite material to be obtained.
Then, together with the bobbin 51, the cylindrical laminate 6 is put in an oven 7, and the phenol resin is semi-cured in the oven 7 while maintaining a predetermined temperature to obtain a CFRP precursor (semi-cured body) 8. The CFRP precursor 8 is extracted, and the CFRP precursor 8 is put into a press die 9 and heat-pressed to be fully cured to obtain a CFRP 10.
Next, the CFRP 10 is cut as it is or if necessary, and then fired in an inert gas atmosphere such that the phenol resin is carbonized to obtain a C / C composite material.

  Below, the specific Example of the manufacturing method of the C / C composite material concerning this invention and a comparative example are demonstrated.

Example 1
Phenol resin that is carbon precursor resin (Sumitomo Bakelite Co., Ltd., industrial phenol resin PR-51697) is diluted with ethanol (phenol: ethanol = 1: 2 by weight) to obtain a phenol resin solution that is a carbon precursor resin solution Got.
A chopped glass fiber (manufactured by Nippon Electric Glass Co., Ltd.) having a fiber diameter of 17 μm and a length of 9 mm is added to the phenol resin solution at a ratio of 1% by weight, and 5000 rpm is used using a process homogenizer (silverson, L4-RT). The mixture was stirred for 30 minutes to obtain a glass fiber-dispersed phenol resin liquid 2.
A PAN-based carbon fiber (TORAY, TORAYCA, M40JB-6000) is passed through the glass fiber dispersion resin liquid, and after the glass fiber dispersion resin liquid is adhered to the carbon fiber, the winding pitch is set on the bobbin of the filament winding apparatus. It was continuously wound so that the number of layers was 1.25 mm.

The hobbin wrapped with the carbon fiber as described above was kept at 60 ° C. for 24 hours using a constant temperature dryer (Advantech Toyo Co., Ltd., FC-610) and precured to prepare a CFRP precursor.
After pre-curing, the CFRP precursor was cut out from the hobbin and subjected to main curing using a heat press machine (Kawanaka Sangyo Co., Ltd., HB200HB) at 150 ° C. and 15 MPa for 1 hour to obtain CFRP.

This CFRP was cut into test pieces of 20 mm square and 3 mm thickness with a diamond cutter. The obtained test piece was fired by holding it at 800 ° C. for 1 hour in an argon atmosphere using a programmed annular electric furnace (As One Co., Ltd., TMF-500N) to obtain a first fired body.
The obtained first fired body is placed in a high performance vacuum substitution type multi-atmosphere furnace (Marusho Electric Co., Ltd., SPX1518-16V) and heated to 1400 ° C. at 15 ° C./min with the furnace filled with argon gas. After being held at 1400 ° C. for 1 hour, held at 1400 ° C. for 1 hour, fired and then cooled in the furnace to obtain a second fired body.

The obtained second fired body was put into a carbon furnace core tube of a graphitization furnace, and current was directly passed through the carbon furnace core tube. After raising the temperature of the carbon furnace core tube to 1000 ° C., the second fired body was fired by supplying a current of 1000 A and holding it for 1 hour. The temperature in the furnace at this time was 2200 ° C. when measured using a radiation thermometer.
Thereafter, the inside of the furnace was cooled with water to obtain a C / C composite material test piece A.

(Comparative Example 1)
Instead of glass fiber, black silicon carbide powder (Pacific Random Co., Ltd., particle size 8 μm) was added at a ratio of 1% by weight to the carbon precursor resin liquid to obtain a silicon carbide dispersed resin liquid.
A C / C composite material test piece B was obtained in the same manner as in Example 1 except that carbon fiber was passed through the silicon carbide dispersed resin liquid instead of the glass fiber dispersed resin liquid.

(Comparative Example 2)
A C / C composite material test piece C was obtained in the same manner as in Example 1 except that the carbon fiber was directly passed through the phenol resin solution of Example 1 in which the glass fiber was not dispersed.

(Comparative Example 3)
Instead of glass fiber, black silicon carbide powder (Pacific Random Co., Ltd., particle size 8 μm) was added at a ratio of 50% by weight to the carbon precursor resin liquid to obtain a silicon carbide dispersed resin liquid.
Then, a C / C composite material test piece D was obtained in the same manner as in Example 1 except that carbon fiber was passed through the silicon carbide dispersed resin liquid instead of the glass fiber dispersed resin liquid.

(X-ray diffraction of C / C composite material)
The C / C composite material test piece A obtained in Example 1 and the C / C composite material test piece D obtained in Comparative Example 4 were each tested on an X-ray diffractometer (Rigaku Corporation, RINT-2200VK). The diffraction pattern was measured by irradiating X-rays from the circumferential direction centering on the test bench, and the results are shown in comparison with FIG.

The measurement method uses general-purpose measurement (concentrated method) D / tex, and the measurement conditions are scanning range 2θ = 10 ~ 80 °, step 0.01 °, speed counting time (scanning speed) 9.0, tube voltage 40 kV, The tube current was 30 mA.
As shown in FIG. 2, it is confirmed that there is a diffraction line peak near θ = 36 °, 60 °, and 72 ° in both the C / C composite material specimen A and the C / C composite material specimen D. did it. When this diffraction line was subjected to identification analysis using analysis software (Rigaku Corporation, PDXL2), it was confirmed that it overlapped with the SiC peak.
From this, in C / C composite material test piece A, it has confirmed that SiC was produced | generated by reaction in the baking step of the glass fiber containing Si element, and carbon precursor resin.

(Temperature dependence test of friction coefficient of C / C composite material)
A friction tester composed of an AC motor, a torque meter, a test piece mounting portion, a load cell, a contact displacement meter, and a heater shown in FIG. 3 is made by itself, and each sample piece of C / C composite material sample pieces A to C is paired. Prepare one by one and attach one of the test pieces to the AC motor side attachment, and fix the other test piece to the upper attachment with a heater so that the upper and lower test piece surfaces overlap. did.
After that, a rotational torque was applied using an AC motor while applying a pressing force of 1.0 MPa between the contact surfaces between the upper and lower test pieces using a weight. In addition, the temperature of the test piece was changed to room temperature, 100 ° C, 200 ° C, and 300 ° C using a heater, and the friction coefficient at each temperature was measured at a rotation speed of 300 rpm, a sampling interval of 5 ms, and a measurement time of 300 s. did.

The measurement result of the friction coefficient of each test piece is shown in comparison with FIG.
As shown in FIG. 4, in the case of test pieces B and C, the friction coefficient is low at room temperature, whereas the test piece A obtained by the production method of the present invention has a temperature of 100 ° C. or higher even at normal temperature. The coefficient of friction is almost the same as or slightly higher than that in the region, indicating that the temperature dependence of the coefficient of friction is reduced.
That is, when the SiC powder is directly added, a C / C composite material having a high friction coefficient up to room temperature (low temperature range) cannot be obtained as in the test piece B, whereas the production method of the present invention is used. It can be seen that it is possible to produce a C / C composite material that does not depend on temperature in the friction coefficient and that can provide a stable friction effect as a friction material not only in a high temperature range but also in a low temperature range.
In addition, as confirmed by the X-ray diffraction, the improvement in the friction coefficient, as the carbon precursor resin is carbonized in the firing step, at least a part of Si element of the glass fiber added in the CFRP, This is because part of the carbon formed from the carbon precursor resin or part of the carbon constituting the carbon fiber reacts to form SiC, resulting in a C / C composite material in which SiC is dispersed inside the carbon layer. It is believed that there is.

(Observation of friction surface of specimen)
After rotating the lower test piece for 300 seconds with the same pressing force and the same rotational speed as those for the measurement of the friction coefficient at normal temperature and 300 ° C. for the test piece A and the test piece C, respectively, as in the temperature dependence test of the friction coefficient. The test piece was removed from the friction tester, the surface of the friction surface was observed using a scanning electron microscope (SEM), and the results were imaged and shown in FIGS.

(Surface observation results)
As shown in FIG. 5 (a), when the test piece A is rubbed at room temperature, carbon fibers oriented in one direction on the surface are exposed on the surface, and indentations appearing as scratch marks in the friction direction (FIG. 5). (A) It was found that a portion surrounded by an ellipse was formed.
As shown in FIG. 5B, when the test piece A is rubbed at 300 ° C., the carbon fiber is not exposed to the surface and the surface is almost entirely covered with fine friction powder of carbon. It was found that a depression (a part surrounded by an ellipse in FIG. 5B) formed as a scratch mark was formed.
The scratch marks in FIGS. 5 (a) and 5 (b) are scratches generated on the friction surface of the test piece because SiC formed in the carbon layer by firing is mixed between the friction surfaces of the test pieces. Can be considered. In addition, when SiC is mixed between the friction surfaces of the test piece, the contact area between the friction surfaces is greatly reduced, and the friction of the C / C composite material obtained by firing the conventional glass fiber-free CFRP. The coefficient is less susceptible to surface influences that have caused temperature dependence. In exchange for this, a large frictional resistance is generated due to the “scratch effect” caused by scraping the friction surface of the other side facing the generated SiC, and the friction coefficient is approximately the same as or slightly higher in the low temperature range (normal temperature) It is thought that it is obtained.
That is, it is considered that the temperature dependence of the friction coefficient is reduced by adding glass fiber to generate SiC inside the C / C composite material.

On the other hand, when the test piece C is rubbed at room temperature, the surface is covered with carbon friction powder as shown in FIG. In (a), it was observed that a portion surrounded by an ellipse was present. That is, since this carbon large friction powder is formed on the friction surface, it is considered that the contact area of carbon decreases and the friction coefficient decreases.
In addition, when the specimen C is rubbed at 300 ° C., as shown in FIG. 6 (b), a carbon dense film is formed with a small amount of carbon-containing friction powder. Can be obtained.

The present invention is not limited to the above-described embodiments and examples. For example, in the above embodiment, the carbon fiber material is passed through the carbon precursor resin liquid and then wound around the bobbin of the winding apparatus to obtain a laminate. You may make it laminate | stack by the method.
In the above embodiment, the CFRP precursor is obtained by being semi-cured in an oven. However, it may be semi-cured at room temperature.

1 Carbon fiber material 2 Phenolic resin liquid (carbonized precursor resin liquid)
3 Glass fiber 4 Immersion tank 5 Winding device 51 Bobbin 6 Cylindrical laminate 7 Oven 8 CFRP precursor 9 Press die 10 CFRP

Claims (6)

A method for producing a carbon fiber-carbon composite material comprising a step of firing a carbon fiber reinforced resin obtained by solidifying a carbon fiber material with a carbon precursor resin to carbonize the carbon precursor resin,
A method for producing a carbon fiber-carbon composite material, wherein glass fibers are dispersed and blended in the carbon fiber reinforced resin. Attaching a glass fiber dispersion liquid in which glass fibers are dispersed in a carbon precursor resin solution to a carbon fiber material;
The method for producing a carbon fiber-carbon composite material according to claim 1, wherein the carbon fiber reinforced resin is obtained by curing the carbon precursor resin after laminating the adherend to which the glass fiber dispersion is adhered.   The carbon fiber carbon composite material according to claim 2, wherein the carbon fiber material is immersed in a glass fiber dispersion tank to adhere the glass fiber dispersion to the carbon fiber.   The carbon fiber carbon composite material according to any one of claims 1 to 3, wherein the carbon precursor resin is a phenol resin.   The manufacturing method of the carbon fiber carbon composite material in any one of Claims 1-4 which disperse | distribute chopped glass fiber in a carbon precursor resin solution.   The manufacturing method of the carbon fiber carbon composite material in any one of Claims 1-5 baked in inert gas atmosphere.