JP4146636B2 - lubricant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubricant that is interposed in a sliding surface to reduce sliding resistance. More specifically, the present invention relates to a lubricant having a small coefficient of friction even in a high temperature atmosphere.
[0002]
[Prior art]
As a conventional example related to the present invention, there is JP-A-11-256176. This publication describes a lubrication effect in a normal temperature state and a lubrication effect in a high temperature state regarding a solid lubricant.
[0003]
Graphite is used as the solid lubricant. Other solid lubricants include, for example, MoS ₂ , ZnS ₂ , Cu ₂ S and the like as metal sulfides. These solid lubricants are considered to have a lubricating action due to the occurrence of slippage in the layered portion due to pressurization because the flat crystal structure is arranged in layers in the molecular structure.
[0004]
When these metal sulfides are used in a high temperature state, the sulfide structure is destroyed by decomposition due to heat and the lubricating action is reduced. Graphite maintains its lubricating effect from its crystal structure at a relatively low temperature, but if it continues to slide in the same state for a long time, the lubricating effect decreases.
[0005]
Such a lubricating action cannot be used under any conditions because a certain temperature range, load condition, change with time, etc. can be maintained within a certain range. In particular, in the case of graphite, if it exceeds 350 ° C., the lubricating effect is lowered even in the air, and it becomes difficult to use it as a solid lubricant.
[0006]
Furthermore, as a conventional example, there is a solid lubricant composed of carbon powder and one or more metal powders selected from Group VIA, Group VIIA and Group VIII of the Periodic Table. In this solid lubricant, on the sliding surface, carbon is graphitized by the catalytic action of the metal, so that the sliding resistance is reduced and the friction coefficient is reduced. As this carbon powder, carbon black or the like is used, and graphite or the like is also used. The blending ratio is 0.05 wt% or more to 0.5 wt% or less for metal powder, and when Ni is used, it is effective when the blending ratio is 0.5 wt% to 2 wt%. is there. As this metal powder, Fe, Co, Cr, Mn, etc. have the same effect.
[0007]
However, judging from the experimental data, the metal powder has little difference between Ni, Fe, Co, Cr, Mn, etc., and it is thought that the same effect will be produced with other metals if it is metal powder. It is done.
Furthermore, when carbon black and metal powder are blended, the atmosphere up to 300 ° C. is effective, and the friction coefficient increases at higher temperatures.
When graphite and metal powder are blended, the friction coefficient increases at 400 ° C. Moreover, it is recognized that there is not much difference from the case of carbon black alone or graphite alone. Therefore, these conventional lubricants are difficult to use in a high temperature atmosphere of 300 ° C. or higher.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and the technical problem to be solved by the present invention is that even if it is exposed to a high temperature atmosphere of 400 ° C or higher, as well as normal temperature, The object is to obtain a lubricant having a small coefficient of friction during sliding.
Another object is to obtain a low friction lubricant even in an atmosphere of water vapor. Furthermore, the manufacturing cost is reduced.
Furthermore, the oxidation resistance of the sliding surface is improved.
[0009]
[Means for Solving the Problems]
The present invention has been made to solve the technical problems as described above, and the technical solution means is configured as follows.
[0010]
Powdery lubricants of this invention relating to claim 1 is a powdered lubricant to lubricate the sliding surfaces of the sliding element for mechanical seals made of carbon or ceramic materials, from 10 wt% 15 The main component is a weight percent aluminum phosphate compound and carbon powder.
[0011]
In the powdery lubricant of the present invention according to claim 1, the sliding surface for sealing the mechanical seal in a high temperature atmosphere of about 500 ° C. is obtained by adding 10 to 15% by weight of an aluminum phosphate compound to the carbon powder. In this case, it is considered from the experimental results that the carbon powder adheres to the sliding surface and the aluminum phosphate compound reacts with the carbon powder attached to the sliding surface to impart oxidation resistance. For this reason, in lubricating the sliding surface to be sealed, a powdery lubricant having heat resistance and a low friction coefficient can be obtained.
This aluminum phosphate compound has a good bondability with a sliding surface of a ceramic (hereinafter also referred to as ceramics) or a sliding part of a carbon material, in particular, sliding of a carbon material (also referred to as a carbon material in a mechanical seal). When used on the surface, it is also recognized that the oxidation resistance of the carbon material is improved. For this reason, when this powdery lubricant is used on the sliding surface of a seal ring made of a carbon material such as a mechanical seal (the seal ring, mating ring or the like is referred to as a sliding part), an excellent lubricating effect is exhibited. In addition, the friction coefficient of the sliding surface is reduced after the start of sliding even at room temperature and in a high temperature atmosphere of around 500 ° C, and the friction coefficient of the sliding surface is reduced and stabilized for a long time even in a high temperature atmosphere of around 500 ° C. It is possible to maintain the sliding state.
[0012]
In the powdery lubricant according to the second aspect of the present invention, the sliding surface of the sliding component to which the lubricant is attached is formed of silicon carbide ceramic.
[0013]
In the powdery lubricant according to the second aspect of the present invention, the ceramic sliding parts bonded with silicon carbide powder can easily retain carbon black in the pores of the sliding surface for a long period of time. become. Further, it is recognized that the aluminum phosphate compound imparts oxidation resistance to the carbon on the sliding surface and improves low friction even in a high temperature atmosphere around 500 ° C. Furthermore, since carbon black easily adheres uniformly to the sliding surface of the silicon carbide ceramic, the manufacturing cost can be reduced.
[0014]
In the powdery lubricant of the present invention according to claim 3, the mechanical seal seals a sealed fluid of gas or water vapor up to about 500 ° C., and the aluminum phosphate compound is aluminum dihydrogen phosphate.
[0015]
In the powdery lubricant of the present invention according to claim 3, when the aluminum phosphate compound is aluminum dihydrogen phosphate, the compatibility with carbon black is good and the sealed fluid is stably sealed for a long time. The friction coefficient of the sliding surface can be reduced. In particular, when powdered aluminum dihydrogen phosphate is used, the blending ratio can be increased, so that carbon black with good compatibility can be kept on the sliding surface for a long time, and the friction coefficient can be reduced even in a high temperature atmosphere around 500 ° C. Is possible.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the lubricant as a preferred embodiment according to the present invention will be described in detail.
[0019]
The lubricant according to the present invention is used for the sliding surface in various forms such as solid and powder. However, in the following, only an example used in powder form is shown as an embodiment, but it is not limited to powder form.
[0020]
FIG. 1 is a cross-sectional view of an essential part of a testing machine 1 that tests the lubricant of the present invention. FIG. 2 is a plan view of the seal ring 10 attached to FIG. FIG. 3 is a cross-sectional view of FIG. Further, FIG. 4 is a cross-sectional view of the mating ring 15 shown in FIG. 1 (this cross-sectional view is a cross section of a radius of a portion having a groove and a radius of a portion having no groove). FIG. 5 is a plan view of the mating ring 15 of FIG.
[0021]
First, before describing the lubricant A of the present invention, the test machine 1 and the test pieces 10 and 15 that have tested the lubricant will be described. Seal ring 10 shown in FIGS. 2 and 3 is a silicon carbide ceramic material. The seal ring 10 has an outer diameter of 35 mm, an inner diameter of 23.5 mm, and a width of 10 mm, and the sliding surface 11 has an outer diameter of 29 mm. A sliding surface 11 is provided on the end surface of the seal ring 10, and a suction groove 12 for the lubricant A having a circumference of 4 and a width of 4 mm and a depth of 1.5 mm along the sliding surface 11. Is provided. The suction grooves 12, the lubricant is adapted to penetrate to the sliding surfaces 11, 16 from the suction grooves 12 in rotation. Further, a thermocouple hole is provided below the center line of FIG. 2 or FIG. This hole is formed at a position 1 mm from the sliding surface 11 with a diameter of 1.0 mm and a depth of 2.8 mm. 2 are semi-circular cutouts that are equally spaced, and are holding recesses for fixing the seal ring 10. The average radius of the sliding surface is rm as shown in FIG.
[0022]
4 and 5 show a mating ring 15 made of a silicon carbide ceramic material. A sliding surface 16 is provided on the end surface of the mating ring 15. Then, it slides relative to the sliding surface 11 of the seal ring 10. The mating ring 15 has an outer diameter of 35 mm, an inner diameter of 19 mm, and a width of 7 mm. The average radius of the sliding surface is rm as shown in FIG. Both the seal ring 10 and the mating ring 15 were tested with a carbon material for both members, and further, one was tested with a carbon material and the other with a silicon carbide ceramic material. The data is omitted.
[0023]
Next, the testing machine 1 that has tested the lubricant will be described. FIG. 1 is a cross-sectional view of the testing machine 1. The lower part of the figure is a rotating shaft 2B rotated by a motor (not shown). A second jig 3B is attached to the upper end of the rotating shaft 2B. This 2nd jig | tool 3B hold | maintains the mating ring 15 rotatably. On the other hand, the fixed shaft 2A is movably held and is loaded with a load W. The first jig 3A is also connected to the lower end of the fixed shaft 2A. The first jig 3 </ b> A is configured to hold the seal ring 10 via the ball 5. The first jig 3 </ b> A is covered with a cover tube 6.
[0024]
In the testing machine 1, the test pieces 10 and 15 are composed of an upper seal ring 10 and a lower mating ring 15. The test pieces 10 and 15 are disposed between the first jig 3 </ b> A and the second jig 3 </ b> B, and the inner diameter side of the test pieces 10 and 15 is formed in the lubricant supply chamber 4. The lubricant A is put into the lubricant supply chamber 4 and tested. Further, a second thermocouple thermometer 8 is connected to the seal ring 10 in a hole for thermocouple. Further, the test pieces 10 and 15 and the jigs 3A and 3B are arranged in an atmosphere of a heating electric furnace (not shown). The atmosphere temperature in the electric furnace is controlled and measured by a first thermocouple thermometer 7 connected to the electric furnace.
[0025]
Further, a torque measuring device 9 is connected to the fixed shaft 2A. The torque measuring device 9 is transmitted to the load cell 9A via the cantilever 9B. The friction coefficient μ was calculated from the following equation by measuring the sliding torque M of the rotating shaft 2B, the load W during rotation, and the average radius rm of the sliding surface.
[0026]
μ = M / (W × rm)
[0027]
Sliding test is a measure of the aging of the friction coefficient μ due to in lubricant ambient temperature 470 ° C around the specimen 10, 15. The raw material of the lubricant A of the present invention contains carbon powder and 10 to 15% by weight of an aluminum phosphate compound. The carbon powder is carbon black or the like. Also, the aluminum phosphate compound aluminum dihydrogen phosphate (trade name: Ashidohosu 75,37,120M etc.) are suitable. In addition, when the blending amount of aluminum dihydrogen phosphate is in the range of 8 to 18% by weight, preferably 10 to 15% by weight, the low friction coefficient is excellent and the low friction coefficient can be maintained even in a high temperature atmosphere. become. When these lubricants A are used by adhering them to seal sliding surfaces or bearing sliding surfaces of carbon parts, ceramic parts, etc., a sliding surface having an excellent low friction coefficient can be obtained by the lubricant A.
[0028]
As a result of the test with the lubricant A of the present invention, the coefficient of friction immediately after the start of sliding shows a value of 0.1 to 0.3, but even when the sliding distance is 150 m, it decreases to 0.2 or less. Even when the sliding distance is 500 m, the value of the friction coefficient μ shows a stable behavior. As a result of observing the sliding surface after the sliding distance of 500 m in this sliding test with the naked eye, it is recognized that the lubricant A is attached to the sliding surface. Therefore, it is considered that the low coefficient of friction is maintained over a long period. Further, in order to impart oxidation resistance to the carbon powder by the aluminum phosphate compound, it is considered that the low friction coefficient is maintained even at high temperatures in the atmosphere or in a humid atmosphere.
[0029]
[Example 1]
The raw material of the lubricant A is carbon black powder having a particle size of 42 nm (Toka Black # 7100F manufactured by Tokai Carbon Co., Ltd.), aluminum dihydrogen phosphate Al (H ₂ PO ₄ ) ₃ Powder (made by Pure Chemical Co., Ltd. ) was used.
[0030]
90% by weight of this carbon black powder and 10% by weight of aluminum dihydrogen phosphate powder were mixed in a wet state with ethyl alcohol. In this mixed state, aluminum dihydrogen phosphate is dissolved in ethyl alcohol. Then, the mixed product is dried to a powder state. This was tested as Lubricant A of Example 1.
[0031]
This test is based on the following conditions.
First, the lubricant A was filled to about 60% in the inner diameters of the seal ring 10 and the mating ring 15 of the tester shown in FIG.
Both the seal ring 10 and the mating ring 15 of the test piece are made of silicon carbide ceramic material.
The sliding surface roughness of the test piece is from 0.05 to 0.08 μm Rz.
Rotation speed of test piece: 200rpm
Test load: 50N
Specimen ambient temperature: 470 ° C
[0032]
Under this condition, the sliding torque M, the load load W, and the sliding surface average radius rm were measured by the testing machine 1, and μ was obtained from the above-described equation of the friction coefficient. FIG. 6 is a graph No1 of the friction coefficient μ showing the relationship with the sliding distance (m) for the lubricant A of Example 1.
In Example 1, immediately after the start of sliding, the coefficient of friction was about 0.1, but thereafter, the behavior of the coefficient of friction was stabilized at a sliding distance of 0.2 or less up to 500 m. Moreover, it is recognized that the lubricant A is adhered to the sliding surface even in this state.
As a result, it can be seen that when used for a mechanical seal device or a sliding part such as a bearing, a stable low coefficient of friction is exhibited even in a high temperature atmosphere of around 500 ° C.
[0033]
[Example 2]
Lubricant A is made of carbon black powder (Tokai Carbon # 7100F manufactured by Tokai Carbon Co., Ltd.) and aluminum dihydrogen phosphate Al (H ₂ PO ₄ ) ₃ powder (produced by Junsei Chemical Co., Ltd.). did.
[0034]
85% by weight of this carbon black powder and 15% by weight of aluminum dihydrogen phosphate powder were mixed in a wet state with ethyl alcohol. In this mixed state, aluminum dihydrogen phosphate is dissolved in ethyl alcohol. Then, the mixed product is dried to a powder state. This was tested as Lubricant A of Example 2.
[0035]
This test is based on the following conditions.
First, the lubricant A was filled to about 60% in the inner diameters of the seal ring 10 and the mating ring 15 of the tester shown in FIG.
Both the seal ring 10 and the mating ring 15 of the test piece are made of silicon carbide ceramic material.
The sliding surface roughness of the test piece is from 0.05 to 0.08 μm Rz.
Rotation speed of test piece: 200rpm
Test load: 50N
Specimen ambient temperature: 470 ° C
[0036]
Under these conditions, the sliding torque M, the load load W, and the sliding surface average radius rm were measured by the testing machine 1, and μ was obtained from the equation of the friction coefficient. FIG. 7 is a graph No 2 of the friction coefficient μ showing the relationship with the sliding distance (m) for the lubricant A of Example 2.
In Example 2, the friction coefficient was about 0.36 immediately after the start of sliding, but thereafter, the behavior of a stable low friction coefficient was exhibited at a sliding distance of 0.2 or less up to 500 m. A slight variation in the coefficient of friction in Example 2 compared to Example 1 is considered to be due to an increase in the amount of aluminum dihydrogen phosphate. However, it can be seen that the coefficient of friction in a high temperature atmosphere is decreasing. Furthermore, adhesion of the lubricant A is observed on the sliding surface even when the sliding distance is over 500 m.
As a result, it can be seen that, when used for a mechanical seal device or a sliding part such as a bearing, it exhibits a low coefficient of friction that is stable for a long time even in a high temperature atmosphere of around 500 °.
[0037]
[Comparative Example 1]
As a raw material for the lubricant B , carbon black powder having a particle size of 42 nm (Toka Black # 7100F manufactured by Tokai Carbon Co., Ltd.) and Ni powder having a particle size of 63 μm or less (manufactured by Kojundo Chemical Laboratory Co., Ltd.) were used.
[0038]
99% by weight of this carbon black powder and 1% by weight of Ni powder were mixed in a wet state with ethyl alcohol. The mixed formulation is then dried to a powder state. This was tested as the lubricant B of Comparative Example 1.
[0039]
This test is based on the following conditions. First, the lubricant B was filled to about 60% in the inner diameters of the seal ring 10 and the mating ring 15 of the tester shown in FIG. Both the seal ring 10 and the mating ring 15 of the test piece are made of silicon carbide ceramic material. The sliding surface roughness of the test piece is from 0.05 to 0.08 μm Rz.
Rotation speed of test piece: 200rpm
Test load: 50N
Specimen ambient temperature: 470 ° C
[0040]
Under this condition, the testing machine 1 uses the sliding torque M, load W, sliding surface average radius rm.
FIG. 8 shows the result of measuring μ and obtaining μ from the equation of the friction coefficient. FIG. 8 is a graph No 3 of the friction coefficient μ showing the relationship with the sliding distance (m) by the lubricant B of Comparative Example 1. Lubricant B containing Ni powder in carbon black showed an unstable frictional behavior in which the friction coefficient was 0.5 or more and moved up and down immediately after sliding until the sliding distance reached 500 m. Moreover, the friction coefficient is 0.8 at the maximum.
[0041]
[Comparative Example 2]
Raw material of the lubricant B, the carbon black having a particle size of 42nm powder (Tokai Carbon Co., Ltd. TOKABLACK # 7100F), use the aluminum dihydrogenphosphate _Al (H 2 _{PO 4) 3} powder (manufactured by Junsei Chemical Co., Ltd.) did. 99% by weight of this carbon black powder and 1% by weight of aluminum dihydrogen phosphate powder were mixed in a wet state with ethyl alcohol. Then, the mixed product is dried to a powder state. This was tested as the lubricant B of Comparative Example 2. Comparative Example 2 is tested under the same conditions using the same model as Comparative Example 1.
[0042]
Under this condition, the testing machine 1 uses the sliding torque M, load W, sliding surface average radius rm.
FIG. 9 shows the result of measuring and determining μ from the equation of the friction coefficient. FIG. 9 is a graph No 4 of the friction coefficient μ showing the relationship with the sliding distance (m) for the lubricant B of Comparative Example 2. This lubricant B containing aluminum dihydrogen phosphate powder in carbon black showed an unstable frictional behavior with an average friction coefficient of 0.5 or more until the sliding distance reached 500 m immediately after sliding. Moreover, the friction coefficient is 0.8 at the maximum.
[0043]
Lubricant B is made of carbon black powder (Tokai Carbon # 7100F manufactured by Tokai Carbon Co., Ltd.) and aluminum dihydrogen phosphate Al (H ₂ PO ₄ ) ₃ powder (produced by Junsei Chemical Co., Ltd.). did. 95% by weight of this carbon black powder and 5% by weight of aluminum dihydrogen phosphate powder were mixed in a wet state with ethyl alcohol. Then, the mixed product is dried to a powder state. This was tested as the lubricant B of Comparative Example 3. Comparative Example 3 is tested under the same conditions using the same model as Comparative Example 2.
[0044]
Under this condition, the testing machine 1 uses the sliding torque M, load W, sliding surface average radius rm.
FIG. 10 shows the measurement of μ and the μ obtained from the equation of the coefficient of friction. FIG. 10 is a graph No 5 of the friction coefficient μ showing the relationship with the sliding distance (m) for the lubricant B of Comparative Example 4. This lubricant B containing aluminum dihydrogen phosphate in carbon black exhibited an unstable frictional behavior with an average friction coefficient of 0.7 or more until the sliding distance reached 500 m immediately after sliding. In addition, the friction coefficient is 0.85 at the maximum.
[0045]
[Comparative Example 4]
Lubricant B is made of carbon black powder (Tokai Carbon # 7100F manufactured by Tokai Carbon Co., Ltd.) and aluminum dihydrogen phosphate Al (H ₂ PO ₄ ) ₃ powder (produced by Junsei Chemical Co., Ltd.). did. 80% by weight of this carbon black powder and 20% by weight of aluminum dihydrogen phosphate powder were mixed in a wet state with ethyl alcohol. The mixed formulation is then dried to a powder state. This was tested as a lubricant B of Comparative Example 4. Comparative Example 4 is tested under the same conditions using the same model as Comparative Example 2.
[0046]
Under this condition, the testing machine 1 uses the sliding torque M, load W, sliding surface average radius rm.
FIG. 11 shows the measurement of μ and the μ obtained from the equation of the coefficient of friction. FIG. 11 is a graph No 6 of the friction coefficient μ showing the relationship with the sliding distance (m) for the lubricant B of Comparative Example 4. Lubricant B containing aluminum dihydrogen phosphate in carbon black showed an increase in the coefficient of friction immediately after sliding, but the coefficient of friction reached an average of 0.4 after the sliding distance exceeded 250 m. Overall, the behavior of friction was somewhat unstable. However, it is recognized that when the sliding distance is increased, a stable behavior is exhibited. Also from this point, the aluminum phosphate can be sufficiently utilized up to the upper limit of 18 wt% . A review of the data from Comparative Examples and Conventional Example for the real施例, lubricant containing 10 to 15 wt% aluminum phosphate, it is recognized that the effect of the excellent low friction.
[0047]
【The invention's effect】
The powder lubricant according to the present invention has the following effects.
According to the powdery lubricant of the present invention according to claim 1, the fluid to be sealed in a high temperature atmosphere from room temperature to around 500 ° C. by adding 10 to 15% by weight of an aluminum phosphate compound to the carbon powder. On the sliding surface that seals, there is an effect that a stable low coefficient of friction can be maintained for a long time. This aluminum phosphate compound has good binding properties with sliding surfaces in sliding parts made of carbon materials or silicon carbide materials, and particularly when used for carbon materials, the acid resistance of the sliding surfaces to be sealed by the carbon materials. It is also recognized that the chemical properties are improved. For this reason, when used for sliding surfaces, such as a mechanical seal, it is also recognized that there exists an outstanding sealing effect. Furthermore, since the aluminum phosphate compound causes carbon to adhere to the sliding surface and the aluminum phosphate compound imparts oxidation resistance to the carbon attached to the sliding surface, it is considered that the heat resistance is also good. In addition, the sliding surface has an effect of maintaining a low friction state even at a normal temperature and a high temperature of about 500 ° C. from the initial sliding stage.
[0048]
According to the powdery lubricant of the present invention according to claim 2, since the carbon black tends to adhere to the sliding surfaces of the sliding parts of the carbon material and the silicon carbide material due to the aluminum phosphate, the low friction coefficient for a long time There is an effect to maintain. Furthermore, since the oxidation resistance of carbon black is improved by the aluminum phosphate on the sliding surface of this sliding component, there is an effect that a low friction coefficient of the sliding surface can be obtained even in a high temperature atmosphere of around 500 ° C. In addition, the manufacturing cost of the lubricant can be reduced.
[0049]
According to the lubricant of the present invention according to claim 3, aluminum dihydrogen phosphate is mixed with carbon and exhibits steam oxidation resistance at about 500 ° as well as oxidation resistance in the atmosphere. Even in an atmosphere with a low friction coefficient, the effect is obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part of a testing machine for testing a lubricant of the present invention.
FIG. 2 is a plan view of a seal ring to be tested by applying the lubricant of the present invention.
3 is a cross-sectional view of the seal ring shown in FIG.
FIG. 4 is a cross-sectional view of a mating ring to be tested by applying a lubricant of the present invention.
FIG. 5 is a plan view of the mating ring of FIG. 4;
6 is a graph showing a friction coefficient No1 of Example 1. FIG.
7 is a graph showing a friction coefficient No2 of Example 2. FIG.
8 is a graph showing a friction coefficient No3 of Comparative Example 1. FIG.
9 is a graph showing a friction coefficient No4 of Comparative Example 2. FIG.
10 is a graph showing a friction coefficient No5 of Comparative Example 3. FIG.
11 is a graph showing a friction coefficient No6 of Comparative Example 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Test machine 2A Fixed axis | shaft 2B Rotating shaft 3A, 1st jig | tool 3B 2nd jig | tool 4 Lubricant supply chamber 5 Ball 6 Cover tube 7 1st thermocouple thermometer 8 2nd thermocouple thermometer 9 Torque measuring instrument 9A Load cell 9B Cantilever 10 Seal ring 11 Sliding surface 15 Mating ring 16 Sliding surface

Claims (3)

A powdery lubricant for lubricating a sliding surface of a sliding part for a mechanical seal made of a carbon material or a ceramic material, comprising 10 to 15% by weight of an aluminum phosphate compound and carbon powder as main components Powdered lubricant. Powdered lubricant of claim 1, wherein the sliding surface of said sliding component to attach the powdered lubricant is formed of silicon carbide ceramics. 3. The mechanical seal is for sealing a gas or water vapor sealed fluid up to approximately 500 ° C., and the aluminum phosphate compound is aluminum dihydrogen phosphate. The powdery lubricant as described.

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