JP2007290926A - Carbon member and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon member which is used as e.g., a sliding member such as a seal for a gas generator and can exhibit high corrosion resistance and good slidability both in high-temperature air and in a high-temperature steam atmosphere. <P>SOLUTION: The carbon member is composed of a carbon base material having pores and a coating film formed on the surfaces of the pores and containing aluminum orthophosphate (Al(PO<SB>4</SB>)). Desirably, the coating film formed on the surfaces of the pores contains a lithium compound in addition to the aluminum orthophosphate (Al(PO<SB>4</SB>)). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a carbon member and a method for producing the same, and more particularly to a carbon member capable of realizing high corrosion resistance and good slidability in both a high temperature atmosphere and a high temperature steam atmosphere and a method for producing the same.

  Generally, a sliding component made of a carbon member is widely used as a sliding component for a sealing device for sealing a fluid. A sliding component made of this type of carbon member has moderate unevenness on the sliding surface in addition to solid lubricity, so a liquid film is formed by a sealing fluid between the sealing sliding surface of the mating sliding member. It can be retained and exhibits excellent lubricating properties.

  Sliding parts made of carbon members are usually mixed, kneaded and molded with an aggregate such as natural graphite, artificial graphite, mesophase, and carbon black, and a binder such as synthetic resin, and then 1000 ° C. Manufactured by firing at ~ 3000 ° C. In the sliding part made of the carbon member manufactured in this way, many pores are formed inside the manufacturing process.

  In addition, a sliding component made of such a carbon member may be used in a high-temperature oxidizing atmosphere of 500 ° C. or higher depending on applications such as a gas generator seal. However, the carbon material has the property of being oxidized in a high-temperature oxidizing atmosphere of 500 ° C. or higher. In particular, the pores formed in the carbon member during the manufacturing process are oxidants and reaction products in the oxidation reaction. Therefore, there is a problem that oxidation exhaustion occurs on the surface of these pores. Therefore, in order to use it stably in a high-temperature oxidizing atmosphere of 500 ° C. or higher, it is necessary to perform various oxidation resistance treatments on the carbon member.

  For example, as a carbon member that can be stably used without being oxidized even in a high-temperature atmosphere of 500 ° C. or higher (in a high-temperature oxidizing atmosphere), a mixed compound of a lithium compound and a phosphoric acid compound other than lithium on the surface of the pores A carbon member having a coating formed thereon is disclosed (for example, Patent Document 1). However, although the carbon member described in Patent Document 1 is excellent in oxidation resistance and slidability in high-temperature air, there is a problem that oxidation resistance is insufficient when used in a high-temperature steam atmosphere. It was.

  Further, as a carbon member that can be stably used without being oxidized even in a high-temperature steam atmosphere, for example, Patent Document 2 discloses at least one metal phosphate of Mg, Ca, Zn, and Al and a colloidal shape. There is disclosed a carbon member whose pores are sealed with an impregnating liquid composed of silica. Patent Document 3 discloses a carbon member obtained by filling the pores with an impregnating liquid composed of phosphate and ultrafine alumina particles and heat-treating them. However, the carbon members described in Patent Documents 2 and 3 have a problem that they are inferior in oxidation resistance and sliding characteristics when used in a high temperature atmosphere.

  That is, the carbon members described in Patent Documents 1 to 3 cannot achieve both oxidation resistance in a high-temperature atmosphere and oxidation resistance in a high-temperature steam atmosphere. Therefore, a carbon member having high oxidation resistance and excellent sliding characteristics has been desired both in these high-temperature air and high-temperature steam atmosphere.

Japanese Patent Laid-Open No. 9-87067 Japanese Patent Laid-Open No. 57-179084 JP 58-69708 A

  The present invention has been made in view of such a situation, and is used as a sliding part such as a seal for a gas generator, and realizes high corrosion resistance and good slidability in both a high temperature atmosphere and a high temperature steam atmosphere. An object of the present invention is to provide a carbon member that can be produced and a method for producing the same.

  As a result of intensive investigations to achieve the above object, the present inventors have formed a film mainly containing aluminum orthophosphate on the surface of the pores formed in the carbon base material. It was found that the above can be achieved, and the present invention has been completed.

That is, the carbon member according to the present invention includes a carbon base material having pores, and a coating film formed on the surface of the pores and containing aluminum orthophosphate (Al (PO ₄ )).

The film formed on the surface of the pores preferably further contains a lithium compound in addition to the aluminum orthophosphate (Al (PO ₄ )).

Moreover, the method for producing a carbon member according to the present invention includes:
Impregnating a carbon base material having pores with an aqueous solution for film formation containing aluminum phosphate;
Heat treating the carbon base material impregnated with the aqueous solution for film formation;
The heat-treated carbon substrate is treated with high-temperature and high-pressure water at a temperature of 180 ° C. or higher to form a film containing aluminum orthophosphate (Al (PO ₄ )) on the surface of the pores of the carbon substrate. And a process.

In the production method of the present invention, preferably,
In addition to the aluminum phosphate, an aqueous solution further containing a lithium compound is used as the aqueous solution for film formation to be impregnated into the carbon substrate having pores,
In addition to the aluminum orthophosphate (Al (PO ₄ )), a film further containing the lithium compound is formed on the surface of the pores of the carbon substrate.

The carbon member of the present invention is formed by forming a film containing aluminum orthophosphate (Al (PO ₄ )) on the pore portion surface of a carbon base material having a pore portion. According to such a carbon member of the present invention, the coating containing the aluminum orthophosphate causes oxidation depletion caused by pores formed in the carbon base material not only in a high temperature atmosphere but also in a high temperature steam atmosphere. Can be effectively prevented. Therefore, the carbon member of the present invention can realize high corrosion resistance and good sliding property in these atmospheres, and can be suitably used as a sliding component such as a gas generator seal.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a sectional view of an essential part showing a sliding test apparatus used in an embodiment of the present invention.
FIG. 2 is a graph showing the results of atmospheric oxidation tests of carbon members according to examples and comparative examples of the present invention.

Carbon member The carbon member of the present invention has a carbon base material having a plurality of pores, and a coating formed on the surface of the pores. In particular, the coating is made of aluminum orthophosphate (Al (PO ₄ )).

  As will be described later, the carbon base material constituting the carbon member of the present invention is mixed with an aggregate made of various carbon materials and a binder such as a synthetic resin, and then molded into a desired shape. Manufactured by firing at 3000 ° C. On the other hand, the carbon base material produced in this way has a plurality of pores produced during the production process, which causes the pores to be consumed, for example, when used in a high-temperature oxidizing atmosphere. May end up.

Therefore, the carbon member of the present invention is formed by forming a film containing aluminum orthophosphate (Al (PO ₄ )) on the surface of a plurality of pores generated inside the carbon base material during the manufacturing process. And the solution of the said problem is aimed at by employ | adopting such a structure.

The film formed on the surfaces of the plurality of pores may be any film that mainly contains aluminum orthophosphate, but preferably further contains a lithium compound in addition to aluminum orthophosphate. By containing a lithium compound in addition to aluminum orthophosphate, an aqueous solution for forming a film for forming these films (for example, an aqueous solution containing an aluminum phosphate and a lithium compound), as described later, The impregnation rate into the carbon substrate can be increased. Therefore, the film formation on the pore surface can be performed more efficiently.
The lithium compound is not particularly limited, and lithium phosphate (Li 3 _{PO 4)} is preferably used.

The coating film is preferably substantially free of other components other than aluminum orthophosphate and preferably added lithium phosphate, and in particular, aluminum metaphosphate (Al (PO ₃ ) ₃ ). It is desirable that no be contained at all. Specifically, regarding aluminum metaphosphate (Al (PO ₃ ) ₃ ), it is desirable that it is below the detection limit by X-ray diffraction measurement. This is because if aluminum metaphosphate is contained, the corrosion resistance in a high-temperature steam atmosphere deteriorates.

  In the carbon member of the present invention, it is sufficient that the above-described coating is formed on at least the surface of the pores of the carbon substrate. For example, in addition to the pores of the carbon substrate, the carbon substrate itself A film may also be formed on the surface.

Method for producing a carbon member Next, the method of manufacturing the carbon member of the present invention will be described.
The carbon member of the present invention is produced by first producing a carbon base material having a plurality of pores, impregnating the carbon base material with an aqueous solution for forming a film containing aluminum phosphate, then subjecting it to a heat treatment, Manufactured by treatment with high-temperature and high-pressure water.

First, a carbon substrate having a plurality of pores is manufactured.
The carbon base material is obtained by mixing and kneading a carbon material and a binder, molding the obtained kneaded product into a desired shape, and then firing the obtained molded body, preferably at 1000 ° C. to 3000 ° C. Can be manufactured.

  Examples of the carbon material include graphite carbon such as graphite (artificial graphite, natural graphite), synthetic resin charcoal obtained by carbonizing phenol resin or epoxy resin, carbonaceous carbon such as charcoal, etc. It is done. Examples of the binder include synthetic resins such as coal tar pitch and phenol resin.

In addition, the carbon base material obtained in this way will have a plurality of pores formed in the manufacturing process. Such a pore part becomes a transfer path of the oxidant and reaction product in the oxidation reaction, so that the surface of these pores is oxidized and causes corrosion. Therefore, in the present invention, in order to prevent such inconvenience, a film containing aluminum orthophosphate (Al (PO ₄ )) is formed on the pore surface of the obtained carbon substrate by the following method. To do.

First, an aqueous solution for forming a coating for forming a coating on the pore surface of the carbon substrate is prepared.
In the present invention, an aqueous solution mainly containing aluminum phosphate is used as the aqueous solution for film formation. The aluminum phosphate, for example, aluminum primary phosphate _{(Al 2 O 3 · 3P 2} O 5 · 6H 2 O) and the like. The content of aluminum phosphate in the aqueous solution can be arbitrarily changed depending on the application.

  Then, using an impregnation apparatus equipped with a container capable of vacuum pressurization, the carbon base material before the impregnation treatment is placed in the impregnation container, sufficiently evacuated, and the aqueous solution for film formation prepared above is injected. (Vacuum impregnation). Thereafter, nitrogen gas or the like is introduced to pressurize the impregnation container, and the pressure is maintained for a certain period of time (pressure impregnation). Next, the pressure is released to atmospheric pressure, the carbon base material is taken out, the surface of the carbon base material is washed and dried, and then the temperature at which the aluminum phosphate compound becomes sufficiently dense due to desorption of crystal water (for example, 600 ° C. Heat treatment is performed at the above temperature). In addition, as an atmosphere at the time of heat processing, the air | atmosphere or nitrogen atmosphere etc. are mentioned.

Next, the carbon base material that has been subjected to the heat treatment is treated with high-temperature and high-pressure water. By performing the treatment with high-temperature high-pressure water, a film containing aluminum orthophosphate (Al (PO ₄ )) can be formed on the surface of the carbon substrate.

The inventors have used a conventional method, that is, a case where a carbon base material is impregnated with an aqueous solution for forming a film containing aluminum phosphate and is simply heat-treated (for example, the above-mentioned Patent Document 1 (Japanese Patent Laid-Open Publication No. 9-2000). No. 87067))) has found that the film formed on the pore surface of the carbon substrate has the following structure. That is, in this case, the coating film formed on the pore surface of the carbon base material contains aluminum metaphosphate (Al (PO ₃ ) ₃ ) as a main component instead of aluminum orthophosphate (Al (PO ₄ )). It was found from the results of X-ray diffraction and the like.
As described above, when the coating formed on the pore portion surface of the carbon base material is mainly composed of aluminum metaphosphate (Al (PO ₃ ) ₃ ), the oxidation resistance in a high-temperature atmosphere. However, when used in a high-temperature steam atmosphere, there was a problem of poor oxidation resistance.

Furthermore, the present inventors have used another conventional method, that is, a case where a mixture of aluminum phosphate and silica is used as an aqueous solution for forming a film (for example, the above-mentioned Patent Document 2 (Japanese Patent Laid-Open No. 57-179084)). In addition, in addition to aluminum orthophosphate (Al (PO ₄ )), the formed film contains aluminum metaphosphate (Al (PO ₃ ) ₃ ) and silica (SiO ₂ ) as main components. It was found from the results of X-ray diffraction and the like.
In this case, the formed coating contains aluminum metaphosphate (Al (PO ₃ ) ₃ ) and silica (SiO ₂ ) in addition to aluminum orthophosphate (Al (PO ₄ )). Therefore, there is a problem that the oxidation resistance is poor in a high-temperature atmosphere. It should be noted that, for example, when alumina is used instead of silica (for example, Patent Document 3 (Japanese Patent Laid-Open No. 58-69708)), the oxidation resistance in a high-temperature atmosphere is inferior for the same reason. There was a problem.

On the other hand, in the present invention, by subjecting the heat-treated carbon base material to a treatment with high-temperature and high-pressure water, aluminum metaphosphate (Al ( PO ₃ ) ₃ ) is reacted to form aluminum orthophosphate (Al (PO ₄ )). That is, in the present invention, the coating formed on the pore portion surface of the carbon base material mainly contains aluminum orthophosphate (Al (PO ₄ )). And in this way, in addition to the case where it is used in a high-temperature air, it is possible to realize excellent oxidation resistance when used in a high-temperature steam atmosphere.

As conditions for performing the treatment with high-temperature and high-pressure water, the temperature is 180 ° C. or higher, preferably 180 to 220 ° C., more preferably 180 to 200 ° C. If this temperature is too low, aluminum metaphosphate (Al (PO ₃ ) ₃ ) remains in the coating, and the above effect cannot be obtained. Further, the pressure in this case is preferably determined in relation to the above-described temperature. In particular, in the present invention, it is preferable that the pressure be equal to or higher than the saturated water vapor pressure at the processing temperature. By setting the pressure to be equal to or higher than the saturated water vapor pressure, water vaporization can be suppressed, and the treatment can be performed with liquid phase water at 180 ° C. or higher.

  In the present invention, the aqueous solution for forming a film for forming a film on the pore surface of the carbon substrate may further contain a lithium compound in addition to aluminum phosphate. By further containing a lithium compound, blowout of the impregnated product can be prevented when the carbon base material is impregnated with the aqueous solution for film formation. Therefore, by further including a lithium compound, the impregnation depth can be increased without being repeatedly impregnated, and further, the work of removing the impregnated material blown out can be reduced. That is, the impregnation rate of the aqueous solution for film formation into the carbon substrate can be increased more efficiently.

Such a lithium compound is not particularly limited as long as it is soluble in the above-described aluminum phosphate, and lithium phosphate (Li ₃ PO ₄ ) or the like is preferably used. Further, the content of the lithium compound in the aqueous solution for forming a film is preferably 0.1 to 5% by weight in terms of lithium with respect to 100% by weight of the entire aqueous solution for forming a film.

  The carbon member of the present invention thus obtained can be used in a high-temperature steam atmosphere in addition to the use in a high-temperature atmosphere without sacrificing characteristics such as lubricity of carbon. Excellent oxidation resistance can be achieved. Therefore, the carbon member of the present invention can be used for various applications that require oxidation resistance, and in particular, it is required to have excellent oxidation resistance in both high-temperature air and high-temperature steam atmosphere. As a sliding material (for example, a sliding material such as a seal for a gas generator), it can be suitably used. In particular, it can be used stably in such a high-temperature atmosphere and a high-temperature steam atmosphere without any change in physical properties.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
First, artificial graphite (average particle size: 10 μm): 50% by weight, coal tar pitch: 45% by weight, and phenol resin: 5% by weight were uniformly mixed, and then using a pressure kneader at a temperature of 160 ° C. for 60 minutes. Kneading was performed to obtain a kneaded product. And after cooling a kneaded material, it grind | pulverized to 100 mesh or less using the free mill, and the molding powder was obtained.

Next, using the obtained molding powder, mold press molding was performed under a molding pressure of 1.3 ton / cm ² for 5 minutes to obtain a molded body of φ100 × φ40 × L50 mm. And the obtained molded object was heat-processed on condition of 2500 degreeC and 1 hour, and the graphitized carbon sintered compact of Shore hardness 80, specific gravity 1.80, and porosity 13% was obtained.

And the block of a magnitude | size of 10x5x40mm was produced from this carbon sintered compact, and it was set as the base material for impregnation evaluation.
Further, a φ23 × φ29 × 10 mm ring was produced from this carbon sintered body, and used as a base material for evaluating sliding properties.

Next, using an impregnation apparatus equipped with a container that can withstand vacuum and pressure, the substrate for impregnation evaluation and the base for sliding property evaluation prepared above were impregnated with an aqueous solution for film formation. Specifically, each base material was put in an impregnation container, and then evacuated to 0.01 kPa, and then impregnated with an aqueous solution for film formation. In this embodiment, as an aqueous solution for film forming, aluminum primary phosphate _{(Al 2 O 3 · 3P 2} O 5 · 6H 2 O: Taki Chemical Ltd. Co.) 38 was used wt% aqueous solution.

After holding for about 20 minutes under the above conditions, pressure impregnation was performed using N ₂ gas under conditions of 0.7 MPa for 60 minutes, and then returned to atmospheric pressure, and each substrate was taken out. Next, each substrate was washed and dried, and then heat-treated in an air atmosphere furnace at 600 ° C. for 1 hour. Finally, the substrate after the heat treatment was treated with high-temperature and high-pressure water at 180 ° C. for 24 hours to prepare samples for impregnation evaluation and sliding property evaluation. The pressure of the high-temperature high-pressure water was set to 1.05 MPa or more, which is a saturated water vapor pressure at a temperature of 180 ° C.

Example 2
In the same manner as in Example 1, except that an aqueous solution to which 3% by weight of lithium phosphate (primary reagent, manufactured by Junsei Chemical Co., Ltd.) was added in addition to primary aluminum phosphate was used as the aqueous solution for film formation. Samples for impregnation evaluation and sliding characteristic evaluation were prepared.

Comparative Example 1
Samples for impregnation evaluation and sliding property evaluation were prepared in the same manner as in Example 2 except that the treatment with high-temperature and high-pressure water was not performed. The sample of Comparative Example 1 corresponds to Patent Document 1 (Japanese Patent Laid-Open No. 9-87067), which is a conventional technique of the present invention.

Comparative Example 2
Instead of the aqueous solution for film formation, a solution in which primary aluminum phosphate and colloidal silica (Snowtex O, manufactured by Nissan Chemical Industries, Ltd.) are mixed at a volume ratio of 1: 1 is used. In the same manner as in Example 1 except that the condition was changed from the condition of 600 ° C. for 1 hour in the atmosphere to the condition of 900 ° C. for 5 hours in the nitrogen atmosphere, and further, the treatment with high-temperature high-pressure water was not performed. Samples for impregnation evaluation and sliding property evaluation were prepared. The sample of Comparative Example 2 corresponds to Patent Document 2 (Japanese Patent Laid-Open No. 57-179084), which is the prior art of the present invention.

Evaluation Tests Each of the samples prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated. Specifically, an oxidation weight loss test was performed using a sample for impregnation evaluation, and a sliding test was performed using a sample for evaluation of sliding characteristics by the following methods.

Oxidation weight loss test The oxidation weight loss test was performed in the high temperature atmosphere (in the atmosphere, 500 ° C., 100 hours) using the samples for impregnation evaluation according to Examples 1 and 2 and Comparative Examples 1 and 2 prepared above, respectively. It was carried out by maintaining the sample in high-temperature steam (in steam, 500 ° C., 50 hours) and in a boiling water immersion atmosphere (boiling water, 100 ° C., 100 hours), and evaluating the weight reduction rate of the sample before and after the test. . In addition, the weight reduction rate was calculated | required by following formula (1).
Weight reduction rate (%) = {(weight before test−weight after test) / weight before test} × 100 (1)
FIG. 2 shows the test results in high-temperature air, and Table 1 shows the test results in high-temperature steam and boiling water immersion atmosphere.

Sliding test The sliding test was performed using the test apparatus as shown in FIG. 1 for the samples for evaluation of sliding characteristics according to Examples 1 and 2 and Comparative Examples 1 and 2 prepared above.
FIG. 1 is a cross-sectional view of a test apparatus used in the sliding test of this example. As shown in FIG. 1, the sliding test of this example includes a seal ring 1 composed of samples for evaluating sliding characteristics according to Examples 1 and 2 and Comparative Examples 1 and 2 prepared above, A mating ring 2 made of a counterpart material is abutted against each other through its sealing surface. The seal ring 1 is fixed with a load W by a fixed shaft 5 via a ball 7 and a jig 3 on the fixed side. On the other hand, the mating ring 2 is freely rotatable by a rotating shaft 6 via a rotation-side jig 4. The rotating shaft 6 can be rotated by a motor (not shown).

  Note that the seal ring 1 and the mating ring 2 shown in FIG. 1 are disposed in an atmosphere of a heating electric furnace (not shown), and the temperature of the heating electric furnace is the first thermoelectric connected to the air furnace. It is controlled by a thermometer 9. The seal ring 1 is formed with a hole for a thermocouple so that the temperature can be measured by a second thermocouple thermometer 10.

  Further, as shown in FIG. 1, a torque measuring device 8 is connected to the fixed shaft 5, and the torque measuring device 8 can measure the sliding torque M of the rotating shaft 6. The friction coefficient can be measured from the sliding torque M, the rotating load W, and the average radius of the sliding surface.

In this example, the sliding characteristics evaluation samples prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were used as seal rings 1, and sliding tests were performed in high-temperature air and warm water vapor, respectively. It was.
The sliding test in high-temperature air was conducted in the following conditions: atmosphere: air, temperature: 500 ° C., sliding speed: 2 m / s, surface pressure: 0.15 MPa, sliding distance: 21600 m, mating material (mate ring 2): carbonization The test was performed under the condition of chromium coating material.
In addition, the sliding test in high-temperature steam was conducted in the following conditions: atmosphere: steam, temperature: 500 ° C., sliding speed: 2 m / s, surface pressure: 0.15 MPa, sliding distance: 21600 m, mating material (Mating Ring 2) : Performed under the condition of silicon carbide material.

  Table 2 shows the results of the sliding test in high-temperature air and high-temperature steam. Table 2 shows the coefficient of friction and the amount of wear of each sample after the end of the sliding test.

Evaluation FIG. 2 shows the results of an oxidation test in Example 1 and Comparative Example 2 in a high-temperature atmosphere. In FIG. 2, the relationship between the retention time and the weight reduction rate of each sample is shown in a graph. As apparent from FIG. 2, Example 1 in which a film made of aluminum orthophosphate (Al (PO ₄ )) was formed on the surface of the pores of the carbon member was obtained by adding primary aluminum phosphate and colloidal silica. The weight reduction rate was suppressed as compared with Comparative Example 2 in which a film was formed by using it, and the result was excellent in oxidation resistance in high-temperature air. The results of Example 2 and Comparative Example 1 were almost the same as those of Example 1.

  Table 1 shows the main test conditions of the oxidation test in Examples 1 and 2 and Comparative Examples 1 and 2 in high-temperature steam and a boiling water immersion atmosphere, and the results of the weight loss rate in each sample.

From Table 1, in Comparative Example 1 in which the treatment with high-temperature and high-pressure water was not performed, the weight reduction rate was high both in high-temperature steam and in a boiling water immersion atmosphere, and the oxidation resistance in these atmospheres was poor. As a result. This is because, in Comparative Example 1, since the treatment with high-temperature and high-pressure water was not performed, the coating formed on the pore portion surface of the carbon member was mainly composed of aluminum metaphosphate (Al (PO ₃ ) ₃ ). This is thought to be due to the fact that it became an ingredient.

On the other hand, in Examples 1 and 2 in which a coating made of aluminum orthophosphate (Al (PO ₄ )) was formed on the surface of the pores of the carbon member by treatment with high-temperature and high-pressure water, in high-temperature steam and boiling water In any of the immersion atmospheres, the weight reduction rate was low, and the oxidation resistance was excellent.

  Table 2 shows main test conditions for the sliding test in Examples 1 and 2 and Comparative Examples 1 and 2 in high-temperature air and high-temperature steam, and after completion of the sliding test for each sample (that is, sliding distance: 21600 m). The coefficient of friction and the amount of wear after the completion of the test are shown.

  From Table 2, in Comparative Example 2 in which the coating was formed using primary aluminum phosphate and colloidal silica, the friction coefficient was increased in the sliding test in the high-temperature atmosphere, and the sliding As a result, the wear amount of the carbon member increased after the test. That is, the result was inferior in sliding properties in a high temperature atmosphere.

  Further, in Comparative Example 1 in which the treatment with the high-temperature and high-pressure water was not performed, the friction coefficient increased in the sliding test in high-temperature steam, and the wear amount of the carbon member after the sliding test ended. As a result. That is, the result was inferior in sliding characteristics in high-temperature steam.

On the other hand, in Examples 1 and 2 in which treatment with high-temperature and high-pressure water was performed and a film made of aluminum orthophosphate (Al (PO ₄ )) was formed on the surface of the pores of the carbon member, In any of the water vapors, the friction coefficient was kept low, the amount of wear of each sliding member was small, and the sliding characteristics were excellent.

Reference Example Using the base material for impregnation evaluation prepared in Example 1, treatment with high-temperature and high-pressure water was performed for 24 hours under the conditions of 100 to 200 ° C. in the same manner as in Example 1. Samples for evaluation of impregnation with different processing conditions were produced by forming a film on the surface of the pores of the material. And about each obtained sample, the composition of the formed film was investigated by X-ray diffraction. The results are shown in Table 3.

From Table 3, by the processing temperature and 160 ° C. or higher, aluminum metaphosphate _{(Al (PO 3) 3)} , it can be confirmed that the change in the aluminum orthophosphate (Al _(PO 4)). Furthermore, by setting the treatment temperature to 180 ° C. or higher, aluminum metaphosphate (Al (PO ₃ ) ₃ ) could not be substantially detected.

FIG. 1 is a cross-sectional view of an essential part showing a sliding test apparatus used in an embodiment of the present invention. FIG. 2 is a graph showing the results of atmospheric oxidation tests of carbon members according to examples and comparative examples of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seal ring 2 ... Mating ring 3 ... Fixed side jig | tool 4 ... Rotation side jig | tool 5 ... Fixed axis 6 ... Rotation axis

Claims (4)

A carbon substrate having pores;
A film formed on the surface of the pores and containing aluminum orthophosphate;
Carbon member having   The carbon member according to claim 1, wherein the film formed on the surface of the pore portion further contains a lithium compound in addition to the aluminum orthophosphate. Impregnating a carbon base material having pores with an aqueous solution for film formation containing aluminum phosphate;
Heat treating the carbon base material impregnated with the aqueous solution for film formation;
Treating the heat-treated carbon base material with high-temperature high-pressure water at a temperature of 180 ° C. or higher to form a film containing aluminum orthophosphate on the surface of the pores of the carbon base material. Manufacturing method. In addition to the aluminum phosphate, an aqueous solution further containing a lithium compound is used as the aqueous solution for film formation to be impregnated into the carbon substrate having pores,
The method for producing a carbon member according to claim 3, wherein a film further containing the lithium compound in addition to the aluminum orthophosphate is formed on the surface of the pore portion of the carbon base material.

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