JP2006045463A - Composition for sliding member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition which is used for sliding materials and can form coating films having low frictional coefficients, excellent abrasion resistance and excellent baking resistance. <P>SOLUTION: This composition for the sliding materials is characterized by comprising a polyamideimide resin and a platy abrasion-inhibiting material which has an aspect ratio of 5 to 100 represented by an average particle diameter/average particle thickness, an average particle diameter of ≤15.0 μm and a Mohs hardness of ≥6, wherein the abrasion-inhibiting material is contained in an amount of 1 to 80 pts.wt. per 100 pts.wt. of the polyamideimide resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composition for a sliding member for forming a coating layer (coating film) of a dry film lubricant for reducing wear coefficient and seizure property while reducing a friction coefficient.

An example of the sliding member is a piston used for an internal combustion engine. When converting heat energy as power in an internal combustion engine, the frictional characteristics between the piston skirt and the cylinder have a strong effect on the efficiency, and when there is no lubrication, a seizure phenomenon occurs and stops immediately. This piston skirt becomes boundary lubrication due to partial oil shortage between the piston skirt and the cylinder when the side pressure increases during the swinging phenomenon that occurs during the vertical movement of the piston, especially during the combustion stroke that receives explosive force, Furthermore, it proceeds to burn-in. For this reason, a coating film is applied to the piston skirt surface (sliding surface) in contact with the cylinder in order to improve durability.
As an example of the composition for a sliding member for forming the above-mentioned coating film, there is one obtained by adding spherical alumina as an antiwear agent to a polyamideimide resin (see Patent Document 1). A polyamideimide resin having a high elongation is used. The coating film formed with this composition absorbs and reduces the contact stress generated when the counterpart material and the sliding member come into contact with each other by the elongation of the polyamideimide resin.
Further, as another example, there is one in which plate-like alumina is added to a resin in order to improve scratch resistance (see Patent Document 2). Plate-like alumina has high sedimentation stability in the resin, and stability during coating is ensured.
JP 2002-53883 A JP 2001-335752 A

In recent years, lubrication conditions have become extremely strict due to the progress of high compression and minimum clearance in response to demands for exhaust gas regulations, low fuel consumption, low noise, and high output. In particular, it is desired that the friction coefficient is even smaller at the sliding portion such as a piston skirt and that the low friction coefficient is maintained for a long time. Conventionally, a resin coating layer composed of a solid lubricant for reducing the coefficient of friction and a binder for holding it improves the sliding characteristics. However, if the blending amount of the solid lubricant is increased in order to reduce the friction coefficient, the wear resistance tends to be lowered. On the other hand, increasing the mechanical strength of the binder to improve wear resistance, seizure resistance, etc. often amplifies the internal stress, impairs the adhesive strength with the substrate, and increases the coefficient of friction.
The present invention has been devised in view of the above points. That is, an object of the present invention is to provide a composition for a sliding member that can form a coating film having a low friction coefficient and excellent wear resistance and seizure resistance.

As a result of repeating the experiment, the present inventors have used a plate-like wear suppressing material having a predetermined hardness and a polyamide-imide resin, thereby achieving a low friction coefficient, excellent wear resistance and seizure resistance. It has been found that a composition for a sliding member capable of forming a film is obtained.
That is, the composition for a sliding member according to the first invention is a plate having an aspect ratio of 5 to 100 expressed by average particle diameter / average particle thickness, and the average particle diameter is 15.0 μm or less. It contains a wear suppression material having a hardness of 6 or more and a polyamideimide resin, and contains 1 to 80 parts by weight of the wear suppression material with respect to 100 parts by weight of the polyamideimide resin.

  Next, the sliding member composition according to the second invention is the sliding member composition according to the first invention, wherein the wear suppressing material is alumina.

  Next, the sliding member composition according to the third invention is the sliding member composition according to the first or second invention, wherein the average particle size of alumina is 1.0 μm or less. Features.

  Next, the sliding member composition according to the fourth invention is the sliding member composition according to the second invention, wherein 10 to 50 parts by weight of alumina is added to 100 parts by weight of the polyamideimide resin. It is characterized by containing.

  Next, a sliding member composition according to a fifth invention is the sliding member composition according to any one of the first to fourth inventions, and the polyamideimide resin has a breaking strength of 100 MPa. Thus, the elongation at break is 20% or more.

According to the present invention, the composition for a sliding member is coated, applied, etc., depending on the particle shape and particle diameter of the wear suppressing material, in particular, by adding the wear suppressing material satisfying the conditions as described above to the composition. The friction coefficient of the coating film surface obtained in this way can be further reduced. Further, even after the surface of the coating film is worn by friction or the like, the friction coefficient of the coating film can be kept low. Furthermore, in the composition for a sliding member of the first invention, in particular, the wear resistance and seizure resistance of the resulting coating film are improved by adding a wear inhibitor having a Mohs hardness of 6 or more to the polyamideimide resin. ing.
Therefore, the present invention provides a sliding member composition capable of forming a coating film having a low coefficient of friction and excellent wear resistance and seizure resistance, thereby reducing friction torque due to sliding and sliding member. It is possible to obtain a coating film that can reduce the wear and the like over a long period of time.

The best mode for carrying out the present invention will be described below.
The composition for a sliding member in the present example contains a polyamideimide resin, a wear suppressing material, and a solid lubricant. Each configuration will be described below.

[Abrasion inhibitor]
As the wear suppressing material, various plate-like inorganic fine particles having a Mohs hardness of 6 or more can be used. For example, alumina such as aluminum oxide, aluminum hydroxide, alumina white and silica alumina, zirconia, tungsten carbide, titanium carbide, silicon carbide, titanium dioxide, iron oxide, feldspar, pumice, orthofeldspar, iridium, quartz, silica, oxidation Examples include beryllium, zirconium oxide, chromium, boron carbide, tungsten carbide, silicone carbide, and diamond. These may be used in combination of two or more, or may be a combination of two or more, or some surface treatment or surface modification. When the Mohs hardness is 6 or more, it is possible to impart good hardness to the coating film obtained from the sliding member composition and to improve the wear resistance and seizure resistance. Also, for example, in a sliding member composition for forming a film applied to a metal surface and a surface rubbed in the presence of lubricating oil, such as a sliding surface of an engine piston skirt, aluminas having a Mohs hardness of 9 It is particularly preferable that good abrasion resistance and seizure resistance can be imparted.

  The shape of the wear-suppressing material is a flat plate shape having an aspect ratio of 5 to 100 represented by average particle diameter / average particle thickness. In the wear suppression material having an aspect ratio lower than 5, the shape approaches a spherical shape, and the effect inherent to the plate-shaped wear suppression material is lost. In addition, in the wear suppression material having an aspect ratio higher than 100, the average particle thickness is reduced with respect to the average particle diameter, and the wear suppression material may be cracked or chipped in a paint dispersion process or the like. Preferably, the aspect ratio of the wear-suppressing material is 5-30. If it is a plate-like wear suppression material having an aspect ratio in this range, it has a thin plate shape with a thin and large smooth surface (because the pointed surface is reduced), and maintains hardness, Aggressiveness against the opponent material can be suppressed. For this reason, also when formed in a coating film, while reinforcing a coating film with the hardness which an abrasion suppression material has, it can suppress favorably that a friction coefficient increases by the presence. Or it is thought that the smoothness of the sliding surface of a coating film can be improved and it can contribute to the fall of a friction coefficient.

  In addition, the plate-like wear-suppressing material having the above aspect ratio is oriented in parallel in the coating film, reducing sharp contact between the formed coating film and the counterpart material, and suppressing the increase in the coefficient of friction is good. It is thought that it is planned. Further, since the expansion and contraction in the film surface direction of the coating film is restricted, the internal stress of the coating film is hardly increased, and it is considered that the adhesiveness between the coating film and the substrate is positively affected. Furthermore, even when the wear-suppressing material is exposed due to the abrasion of the coating film, since it is oriented parallel to the film surface direction of the coating film, an increase in the friction coefficient is suppressed as compared with the spherical wear-suppressing material.

  Here, the aspect ratio is average particle diameter / average particle thickness, and is a value determined by the following method. For the average particle thickness (average particle thickness) or the average particle size (average particle size), any 10 particles are selected by observing the wear-suppressing material with a scanning electron microscope. The diameter was measured, the average particle thickness was 10 arithmetic averages, the average particle diameter was (major axis + short axis) / 2, and 10 arithmetic averages.

  The average particle size of the wear suppressing material is 15.0 μm or less. In the wear suppression material having an average particle diameter exceeding 15.0 μm, the protrusion amount of the wear suppression material from the coating film surface is increased, the friction coefficient is increased, and the aggressiveness to the counterpart material is likely to be increased. Preferably, when the average particle size is 1.0 μm or less, the aggressiveness to the counterpart material is low, and the effect of reducing the friction coefficient is exhibited well.

Moreover, 1-80 weight part of an abrasion suppression material is contained with respect to 100 weight part of polyamideimide resin. If the wear-suppressing material is less than 1 part by weight, it is difficult to obtain a significant effect by adding the wear-suppressing material. On the other hand, when the wear suppression material is more than 80 parts by weight, the amount of the polyamide-imide resin that is a binder is relatively reduced, so that the adhesiveness to the substrate is lowered and the coating film is easily peeled off.
Preferably, the amount of the wear inhibitor is 10 to 50 parts by weight with respect to 100 parts by weight of the polyamideimide resin. Within this range, the effect of reducing the friction coefficient and improving the wear resistance and seizure resistance by the wear suppressing material can be exhibited well.

[Polyamideimide resin]
As the polyamide-imide resin, a known polyamide-imide resin used in the sliding member composition can be selected. As for the mechanical strength of the polyamide-imide resin, it is preferable that the breaking strength is 100 MPa or more and the breaking elongation is 20% or more.
When the breaking strength is less than 100 MPa, the formed coating film may be broken due to insufficient strength due to sliding with the counterpart material. For this reason, it is difficult to ensure the wear resistance of the coating film.
When the elongation at break is less than 20%, the effect of dispersing the contact stress and reducing the coefficient of friction becomes insufficient.
More preferably, a polyamideimide resin having a breaking strength of 150 MPa and a breaking elongation of 50% or more is used. If it is a polyamide-imide resin having a mechanical strength in this range, it is possible to form a coating film having a low coefficient of friction and good wear resistance and seizure resistance in combination with the above-described wear suppression material. It can be set as the composition for members, and especially wear resistance can be improved.
The breaking strength of the polyamideimide resin is desirably 500 MPa or less. This is because a polyamideimide resin having a higher breaking strength has a higher molecular weight and a higher viscosity, which increases the number of man-hours and costs for coating.
The breaking elongation of the polyamideimide resin is desirably 100% or less. This is because a polyamide-imide resin having an elongation at break higher than this increases the amount of deformation of the coating film and decreases the adhesion to the substrate.

  The breaking strength of the polyamideimide resin used in the present invention and the elongation at break of the polyamideimide resin used in the present invention are measured by a film of polyamideimide resin. The polyamideimide resin used in the present invention is cast onto a biaxially stretched polyethylene terephthalate film so that the thickness after drying is 20 μm, and dried at 150 ° C. for 20 hours. Next, the polyamide-imide film is peeled off from the polyethylene terephthalate film, adjusted to a width of 10 mm and a measurement length of 40 mm, and a tensile test is performed with a tensile tester. The pulling speed at this time is 20 mm / min, and the measurement temperature is 25 ° C.

[Solid lubricant]
As the “solid lubricant” in the present embodiment, a known solid lubricant can be used.
For example, as a solid lubricant, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene Fluorine compounds such as fluoride and polychlorotrifluoroethylene, sulfides such as molybdenum disulfide (MoS ₂ ) and tungsten disulfide (WS ₂ ), layered scales such as graphite (graphite), fluorinated graphite, boron nitride and mica Materials, soft metals such as lead, zinc and copper, and melamine cyanurate.

The solid lubricant is included in an amount of 5 to 250 parts by weight with respect to 100 parts by weight of the polyamideimide resin. When the solid lubricant is less than 5 parts by weight, the effect of reducing the friction coefficient and wear resistance is small. On the other hand, if the solid lubricant is more than 250 parts by weight, the coating film formed is likely to be worn due to the relatively small amount of the polyamide-imide resin as a binder, and the solid lubricant has a reduced holding power and is solid. It becomes easy to drop off from the coating film on which the lubricant is formed, and the coating film cannot have excellent wear resistance.
Preferably, the solid lubricant is 10 to 150 parts by weight with respect to 100 parts by weight of the polyamideimide resin. Within this range, good low friction coefficient, wear resistance, and seizure resistance can be obtained.

  The average particle size of the solid lubricant is preferably 15.0 μm or less. Considering that the film thickness of the coating film formed on the surface of the sliding member is approximately 5 to 25 μm, it is preferable to set the film thickness within this range according to the thickness of the coating film. If the maximum particle size of the solid lubricant is larger than the film thickness of the coating film, the solid lubricant tends to fall off the coating film.

  In the present invention, the properties of the coating film can be modified by a general additive in addition to the above components. These additives include dispersants that help disperse wear inhibitors and solid lubricants, silane coupling agents that help improve adhesion and adhesion to wear inhibitors, and leveling that controls surface tension. Agents, surfactants, and thickeners that control thixotropic properties.

[Coating method]
A known coating method can be adopted as the coating method.
First, the polyamide-imide resin is dissolved using an organic solvent. The organic solvent can be used without particular limitation as long as it is an organic solvent that can dissolve the polyamideimide resin.
For example, NMP (N-methyl-2-pyrrolidone) can be used. A mixed solvent obtained by adding an aromatic solvent such as xylene, a ketone solvent such as methyl ethyl ketone, or an ester solvent such as ethyl acetate to NMP can be used.
Next, the solid lubricant and the wear suppressing material are added to the solution in which the polyamideimide resin is dissolved, and the solid lubricant and the wear suppressing material are dispersed for an appropriate time with a ball mill or the like to prepare the composition for the sliding member of this example. can do.

The sliding member composition of this example prepared in this manner is applied to the sliding surface of the sliding member. The sliding member is a member to which a coating film is applied by a known sliding member composition such as a sliding member for an automobile, a sliding member for an OA device, or a sliding member for a weak electric device. Moreover, the material of the sliding member or sliding surface to which the composition for sliding member of the present embodiment can be applied is not particularly limited, and there are metals such as aluminum and iron, alloys, rubber, plastics, elastomers, and the like. . Various coating instruments can be used for application of the composition for a sliding member. Examples of coating equipment include brushes, rollers, roll coaters, air sprays, airless sprays, electrostatic coating machines, immersion coating machines, electrodeposition coating machines, screen printing machines, pad printing machines, and gravure coaters.
After applying the composition for a sliding member, the polyamide-imide resin is baked at a temperature capable of drying and curing to form a coating film. In addition, although baking temperature is not specifically limited, Generally, it bakes for 5 to 180 minutes with the calcination temperature of the range of normal temperature to 350 degreeC. Moreover, the film thickness of the coating film after baking is although it does not specifically limit, Generally, it is 1-50 micrometers, Preferably it is 5-25 micrometers.

The sliding surface of the sliding member may be subjected to preliminary treatment such as alkali degreasing and solvent degreasing, shot blasting, etching, and chemical conversion treatment as necessary.
Moreover, the composition for sliding members of the present Example can be applied also to the sliding surface of the sliding member which gave the undercoat and the precoat.

[Test example]
Hereinafter, specific examples will be described. [Table 1] shows the compositions of the constituent elements contained in the sliding member compositions of Examples 1 to 5 and Comparative Examples 1 to 4. The test results are shown in [Table 2] to [Table 4] described later. In addition, this test example does not restrain this invention.
The materials blended in each example and comparative example are as follows.
First, as the polyamideimide resins of Examples 1 to 4 and Comparative Examples 1 to 4, polyamideimide resins having a breaking strength of 150 MPa and a breaking elongation of 88% were used. Further, as the polyamideimide resin of Example 5, a polyamideimide resin having a breaking strength of 88 MPa and a breaking elongation of 17% was used.
Next, plate-like alumina having an average particle diameter of 0.6 μm (product name: YFA00610, manufacturer name: Kinsei Matech, aspect ratio: 5 to 15) was used as the wear suppressing material of Examples 1 to 3 and 5. In addition, plate-like alumina having an average particle diameter of 2.5 μm (product name: YFA02025, manufacturer name: Kinsei Matech, aspect ratio: 20 to 30) was used as the wear suppressing material of Example 4. Further, spherical alumina having an average particle diameter of 0.4 μm was used as the wear suppressing material of Comparative Example 2. Further, as the wear suppressing material of Comparative Example 3, scaly mica having an average particle diameter of 5 μm was used. Further, spherical nickel having an average particle diameter of 0.4 μm was used as the wear suppressing material of Comparative Example 4.
Next, PTFE having an average particle diameter of 0.3 μm was used as the solid lubricant in Examples 1 to 5 and Comparative Examples 1 to 4.
Next, Comparative Example 5 (not shown in Table 1) was used as one of Comparative Examples of (Measurement Method of Critical Load). In Comparative Example 5, 5 parts by weight of PTFE (average particle diameter 0.3 μm), 50 parts by weight of molybdenum disulfide, and 14 parts by weight of graphite are added to 100 parts by weight of polyamideimide resin having a breaking strength of 88 MPa and a breaking elongation of 17%. It was set as the composition for sliding members to contain.

A method for measuring the friction coefficient, seizure load, and wear amount will be described in order.
(Method for Measuring Friction Coefficient) In this example, a friction coefficient measurement test was conducted using a thrust tester 1 (Orientec Co., Ltd.) shown in FIG.
A plate-shaped member (t3 × 30 × 30 mm, material AC8A, roughness Rz = 1 μm) was used as the test plate 16. As shown in FIG. 1, the upper surface (first sliding surface 14) of the test plate 16 was subjected to solvent degreasing as a pretreatment.
The composition for sliding member of each example and each comparative example was applied to the first sliding surface 14 by spraying and dried (180 ° C., 90 minutes) to form a coating film. The film thickness of the coating film was 10 μm.

In addition, a hollow cylindrical member (outer diameter φ25.6 mm, inner diameter φ20 mm, material FC250, roughness Rz = 1 μm) was used as the first counterpart material 12. The first mating member 12 was placed on the first sliding surface 14 to which the coating film was applied. In this state, the test plate 16 was rotated in the direction of the arrow 18 in FIG. 1 (rotation speed 72 m / min).
Then, after acclimation rotation (applying a pressing load of 245 N for 10 minutes), the pressing load is applied to the first mating member 12 from the direction of the arrow 10 in FIG. 1, and the pressing load is increased at a constant cycle (245 N / 2 min). It was. And the friction coefficient at the time of pressing load 245N, 980N, 2940N, 4900N was measured.
In addition, the said test was done under lubrication of lubricating oil (mineral oil; 5W-30). The oil temperature of the lubricating oil was 80 ° C.

(Measurement method of seizure load) Using the above-described thrust tester 1 (manufactured by Orientec Co., Ltd.), the first counterpart material is similarly applied to the first sliding surface 14 created under the same conditions as the friction test conditions. 12 and the test plate 16 was rotated while increasing the pressing load under the same conditions. When the friction coefficient of the first sliding surface 14 with respect to the first mating member 12 exceeded 0.10, “when seizure occurred” was measured and the load at that time was measured as the seizure load.

(Measurement Method of Wear Amount) In this embodiment, a wear amount measurement test was performed using a block-on-ring tester 2 (manufactured by FALEX LFW-1, FALEEX CORPORATION) shown in FIG.
As the test material 22, a block-shaped member (6 × 16 × 10 mm, material AC8A, roughness Rz = 1 μm) was used. The lower surface (second sliding surface 24) of the test material 22 as viewed in FIG. 2 was subjected to solvent degreasing as a pretreatment. The sliding member composition of each example and each comparative example was applied to the second sliding surface 24 by spraying and then dried (180 ° C., 90 minutes) to form a coating film. The film thickness of the coating film was 10 μm.

Further, a ring-shaped member (outer diameter φ35 mm, thickness 8 mm, material FC250 (gray cast iron), roughness Rz = 1 μm) was used as the second counterpart material 26. The second mating member 26 was brought into contact with the second sliding surface 24. In this state, the second counterpart material 26 was rotated in the direction of arrow 28 in FIG. 2 (rotational speed 5 m / min), and a pressing load (55 N) was applied to the test material 22 from the direction of arrow 20 in FIG. The amount of wear (μm) of the coating film was measured after 5 minutes from the start of the test.
In addition, the said test was done under lubrication of lubricating oil (mineral oil; 5W-30). The oil temperature of the lubricating oil was 80 ° C.

(Measuring method of critical load) In this example, the critical load was measured using a load fluctuation type frictional wear tester (manufactured by Shinto Kagaku Co., Ltd.).
A load fluctuation type frictional wear tester (not shown) is composed of a plate-shaped test piece steel plate (SPCC) and a counterpart steel ball (diameter 1/8 inch, material SUJ-2).
The composition of Example 1 and Comparative Examples 2, 3, 5, and 6 was applied to one surface of the test piece steel plate and dried at 180 ° C. for 90 minutes to form a coating film having a thickness of 10 μm as a sliding surface. The test piece steel plate was slid back and forth (speed: 15 mm / sec) (with a durability of 200 cycles) in a state where the mating steel ball was pressed against the sliding surface. The load at the time of pressing the mating steel ball against the sliding surface is varied (0 gf to 1000 gf), and the load when the mating steel ball reaches the steel material that is the base of the test piece steel plate is defined as “critical load (gf)” I read it.
In addition, the said test was done under lubrication of lubricating oil (mineral oil; 5W-30). The oil temperature of the lubricating oil was 80 ° C.

[Discussion]
First, the friction coefficients in Examples 1 to 5 and Comparative Examples 1 to 4 are compared based on [Table 2] and [Table 3].
First, the friction coefficients of Examples 1 to 5 were lower than those of Comparative Example 2. Thus, it was found that the coating film to which the flat plate-like alumina was added had a lower coefficient of friction than the coating film to which spherical alumina was added.
Further, the friction coefficients of Examples 1 to 3 were lower than those of Example 4 at the pressing loads 980N to 4900N. The friction coefficient of Example 4 exceeded 0.02 at a pressing load of 2940N. On the other hand, the friction coefficients of Examples 1 to 3 did not exceed 0.02 at a pressing load of 980N to 4900N. From this, the coating film obtained by the composition to which alumina having an average particle diameter of 0.6 μm is added has a coefficient of friction more than that of the coating film obtained from the composition to which alumina having an average particle diameter of 2.5 μm is added. I found it smaller.

  The friction coefficient of Example 1 was lower than the friction coefficients of Example 2 and Example 3 in the range of the pressing loads 245N to 4900N. From this, it becomes clear that it is more preferable to add 30 parts by weight of plate-like alumina having an average particle diameter of 0.6 μm and a Mohs hardness of 9 to 100 parts by weight of the polyamideimide resin. It was.

  Further, the friction coefficient of Example 5 exceeded 0.02 at a pressing load of 4900N. On the other hand, the friction coefficient of Example 1 did not exceed 0.02 in the range of the pressing loads 245N to 4900N as described above. As a result, it was found that the coefficient of friction was further reduced in the coating film to which the polyamideimide resin having high mechanical strength was added.

  Next, when the amount of wear was examined, the amount of wear in Examples 1 to 5 was less than the amount of wear in Comparative Example 1. Moreover, the abrasion loss of Examples 1-5 was smaller than the abrasion loss of the comparative examples 3 and 4 to which mica and nickel with Mohs hardness 5 or less were added. On the other hand, Comparative Example 2 containing a wear suppression material of spherical alumina (Mohs hardness 9) has an equivalent amount of wear, and Examples 1 to 5 have a reduced friction coefficient compared to the comparative example. It was found to have good wear resistance. In particular, in Example 1, although the friction coefficient is low, the amount of wear is small, and it is more preferable to add 30 parts by weight of plate-like alumina having a Mohs hardness of 9 in terms of reducing the friction coefficient and improving the wear resistance. It became clear.

Next, the seizure resistance was examined. In the range of the pressing load of 245N to 4900N, no seizure occurred in the coating films of Examples 1 to 5, but the pressing load of 4900N and Comparative Examples 1, 3 and 4 Baking occurred in the coating film. As a result, it was found that the coating film obtained from the composition to which alumina having a Mohs hardness of 9 was added had higher seizure resistance than the coating film from a composition to which mica or nickel having a Mohs hardness of 5 or less was added.
Furthermore, when the critical load was examined, the critical load of Example 1 was larger than the critical loads of Comparative Examples 2, 3, 4, and 5. From this, it was found that the coating film of Example 1 was superior in load resistance to the coating films of other comparative examples. In particular, Example 1 containing plate-like alumina was found to be high in strength and difficult to break even as compared with Comparative Example 2 containing spherical alumina.

It is the schematic of a thrust testing machine. It is a schematic diagram of a block on ring testing machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thrust testing machine 2 Block-on-ring testing machine 12 1st mating material 14 1st sliding surface 16 Test plate 22 Test material 24 2nd sliding surface 26 2nd mating material

Claims (5)

A wear suppressant having a plate shape with an aspect ratio of 5 to 100 represented by average particle diameter / average particle thickness, an average particle diameter of 15.0 μm or less, and a Mohs hardness of 6 or more;
Containing a polyamide-imide resin,
A composition for a sliding member, comprising 1 to 80 parts by weight of the wear suppressing material with respect to 100 parts by weight of the polyamideimide resin. It is a composition for sliding members of Claim 1, Comprising:
The composition for a sliding member, wherein the wear suppressing material is alumina. The composition for a sliding member according to claim 1 or 2,
The composition for a sliding member, wherein the wear suppressing material has an average particle size of 1.0 μm or less. It is a composition for sliding members of Claim 2, Comprising:
A composition for a sliding member, comprising 10 to 50 parts by weight of the alumina based on 100 parts by weight of the polyamideimide resin. It is a composition for sliding members in any one of Claims 1-4, Comprising:
The composition for a sliding member, wherein the polyamideimide resin has a breaking strength of 100 Mpa or more and a breaking elongation of 20% or more.

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