A sliding bearing and a method for producing and using the same

Abstract

This invention belongs to the technical field of surface protective coatings for sliding bearings, specifically relating to a sliding bearing, its preparation method, and its application. The sliding bearing includes a bearing substrate and a surface protective coating disposed on its surface. The surface protective coating is prepared from polyamide-imide resin, modified tin whiskers, graphite, and molybdenum disulfide. The modified tin whiskers, treated with a silane coupling agent, have a specific diameter and aspect ratio, forming a three-dimensional thermally conductive network with graphite and molybdenum disulfide within the resin substrate. Under boundary lubrication conditions, they synergistically induce the formation of a continuous and uniform composite solid lubrication transfer film. This invention also provides a method for preparing the sliding bearing, including dispersing the components in a solvent to obtain a composite slurry, coating it onto the surface of the bearing substrate, and curing it through a gradient temperature rise process to obtain the finished product. This sliding bearing possesses both excellent thermal conductivity and heat dissipation performance and an ultra-low coefficient of friction, exhibiting excellent anti-scratch capability, self-lubricating properties, and operational stability under extreme operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of surface protective coating technology for sliding bearings, specifically relating to a sliding bearing, its preparation method, and its application. Background Technology

[0002] With the rapid development of modern industries such as automobiles, ships, and heavy equipment manufacturing, high-power-density engines have become the core development direction of power systems. As a key and vulnerable component in the engine that bears heavy loads and high-speed rotation, the working environment of sliding bearings has become increasingly extreme and harsh. Under actual engine operating conditions, sliding bearings need to withstand the severe tests of high-speed rotation, local high temperature, instantaneous high pressure, and boundary lubrication and mixed friction during start-up and shutdown. The functional protection of the bearing's inner surface plays an irreplaceable role in isolating direct metal-to-metal contact and ensuring stable system operation.

[0003] For the protection and performance improvement of sliding bearings, traditional optimization methods in the industry mainly focus on macroscopic structural design and lubrication system improvements. For example, by refining the bearing profile and optimizing the oil groove and oil passage structure, the aim is to guide the lubricating oil to form a more ideal hydrodynamic lubricating oil film during operation; or by improving the chemical composition and physical properties of the lubricating oil itself and formulating more efficient additives to enhance the oil film's load-bearing capacity and wear-resistant and friction-reducing properties under extreme operating conditions. These mechanical structural designs and conventional optimizations of fluid lubricants constitute the mainstream technical approach in the industry for ensuring bearing operation.

[0004] However, facing the ever-increasing peak burst pressure and intense thermal loads of high-power-density engines, relying solely on macroscopic structural improvements and oil film optimization has gradually revealed its limitations. Under conditions of frequent start-stop cycles or localized oil shortages caused by instantaneous extremely high pressure, direct metal-to-metal contact due to boundary friction is still difficult to completely avoid. Therefore, the industry has begun to utilize surface modification technology to create composite protective coatings on the bearing substrate surface as an important anti-scuffing and friction-reducing technology. Currently, such solutions typically employ a polymer matrix resin combined with friction-reducing fillers and thermally conductive fillers, coated onto the bearing substrate surface.

[0005] However, such solutions still face several practical challenges. From the perspective of the synergistic construction of thermal conductivity and lubrication, the high thermal conductivity of the coating depends on the formation of a three-dimensional percolation network of thermally conductive fillers in the resin matrix. Meanwhile, the low friction characteristics under boundary lubrication conditions require the layered solid lubricant to easily undergo interlayer slip under frictional shearing and spread to form a continuous transfer film on the mating surfaces. High-hardness, high-modulus thermally conductive fillers form stable thermal conduction pathways, which severely pins and hinders the plastic rheology and film formation of the soft layered lubricant phase under shear, leading to an increase in the coefficient of friction. Conversely, if the volume ratio of the lubricant filler is increased to ensure the continuity of the transfer film, a large amount of low-thermal-conductivity layered material will encapsulate and isolate the thermally conductive filler particles, weakening or interrupting the thermal conduction pathways, drastically increasing the interfacial thermal resistance, and making it difficult to improve the coating's thermal conductivity. Meanwhile, the uniform dispersion of multi-component fillers in resin slurry also faces difficulties. Thermally conductive fillers and anti-friction fillers with different morphologies and surface properties are prone to agglomeration or phase separation due to thermodynamic incompatibility, making it difficult to achieve ordered spatial gradation and network interpenetration. This results in the formation of mutually separated thermally conductive and lubricating zones inside the coating, making it difficult to work synergistically and instead causing local heat accumulation and increased wear. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a sliding bearing, its manufacturing method, and its application.

[0007] The purpose of this invention is to provide a surface coating solution for sliding bearings that combines high thermal conductivity and ultra-low friction to improve the service life and operational stability of bearings under extreme boundary lubrication conditions.

[0008] The first aspect of the present invention provides a sliding bearing, including a bearing substrate and a surface protective coating disposed on the surface of the bearing substrate, the surface protective coating being prepared from raw materials including polyamide-imide resin, modified tin whiskers, graphite and molybdenum disulfide.

[0009] As a further optimization of the above-mentioned sliding bearing, the raw material for the surface protective coating includes the following components in parts by weight: Polyamide-imide resin: 45-55 parts; Modified tin whiskers: 10-20 parts; Graphite: 10-20 parts; Molybdenum disulfide: 15-25 parts.

[0010] As a further optimization of the above-mentioned sliding bearing, the preferred amount of graphite is 15±2 parts; the preferred amount of molybdenum disulfide is 20±2 parts.

[0011] As a further optimization of the aforementioned sliding bearing, the modified tin whiskers have a diameter of 1~5μm and an aspect ratio of 10~50.

[0012] As a further optimization of the aforementioned sliding bearing, the modified tin whiskers are tin whiskers modified with a silane coupling agent.

[0013] As a further optimization of the above-mentioned sliding bearing, modified tin whiskers are prepared by the following method: tin whiskers are added to an ethanol-water solution containing 5wt% silane coupling agent KH570, stirred and reacted at 60°C for 2 hours, and then filtered, washed and vacuum dried.

[0014] As a further optimization of the aforementioned sliding bearing, the bearing substrate is a copper-based bearing substrate with an aluminum-tin sputtering layer, and a surface protective coating is applied to the surface of the aluminum-tin sputtering layer.

[0015] A second aspect of the present invention is to provide a method for preparing the above-mentioned sliding bearing, comprising the following steps: Step S1: Disperse polyamide-imide resin, graphite, molybdenum disulfide and modified tin whiskers in a solvent to obtain a composite slurry; Step S2: Apply the composite slurry to the surface of the bearing substrate to form a coating; Step S3: Curing the coating to obtain the sliding bearing.

[0016] As a further optimization of the above preparation method, a step of modifying tin whiskers is included before step S1: the tin whiskers are placed in a solution containing a silane coupling agent for surface treatment to obtain modified tin whiskers; in step S1, the components are dispersed evenly by a combination of ultrasonic dispersion and mechanical stirring; wherein, the ultrasonic power is 600~1000W and the time is 30~90min; the mechanical stirring speed is 300~800r / min and the time is 1~3h.

[0017] As a further optimization of the above preparation method, in step S2, the composite slurry is coated onto the surface of the bearing substrate by spraying; the bearing substrate is a copper-based bearing substrate with an aluminum-tin sputtering layer.

[0018] As a further optimization of the above preparation method, in step S3, the curing treatment is a gradient temperature curing process: first, the temperature is raised from room temperature to 120°C and held for 0.5 to 2 hours, then the temperature is raised to 200°C and held for 1 to 3 hours, and finally cooled to room temperature.

[0019] A third aspect of the present invention is to provide the application of the above-mentioned sliding bearing for use in engine main bearings, connecting rod bearings, or bushings.

[0020] Beneficial effects The copper-based bearings with surface coatings prepared by this invention possess significant technical advantages and promising industrial application prospects. By introducing modified tin whiskers with specific morphologies into a polyamide-imide resin matrix and spatially grading them with a compounded graphite and molybdenum disulfide solid lubricant, the components generate deep physicochemical complementarity and interfacial rheological synergy during curing, film formation, and boundary oil lubrication friction. On the one hand, the one-dimensional whisker-like modified tin and the layered solid lubricant form a dense, interwoven three-dimensional heat conduction network within the coating, significantly improving the heat dissipation efficiency of the coating. On the other hand, under high-pressure shear conditions of the friction pair, the low-shear-strength tin whiskers readily undergo synergistic lubrication rheology with the layered graphite and molybdenum disulfide, thereby inducing the formation of a strong, continuous, and highly uniform composite solid lubricant transfer film at the bearing friction interface. The organic combination of this multi-dimensional, multi-filler micro-network construction and rheological lubrication mechanism enables the coating to achieve a perfect balance between high thermal conductivity and ultra-low friction coefficient and excellent boundary oil lubrication self-lubrication performance, greatly improving the service life and operational stability of copper-based bearings. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope (SEM) image of tin whiskers.

[0022] Figure 2 This is a schematic diagram of the bearing cross-section.

[0023] Figure 3 The image shows the microscopic state of the bearing cross-section prepared in Example 1.

[0024] Figure 4 This is a microscopic view of the bearing cross-section prepared in Example 2.

[0025] Figure 5 This is a microscopic view of the bearing cross-section prepared in Example 3. Detailed Implementation

[0026] The present invention is further illustrated below with specific embodiments. These embodiments are exemplary and intended to illustrate the problem and explain the present invention, and are not intended to be limiting.

[0027] Raw material and process parameter description Tin whiskers: The tin whiskers used in this invention have a diameter of 1~5μm and an aspect ratio of 10~50, and their scanning electron microscope morphology is as follows. Figure 1 As shown.

[0028] Gradient temperature curing process: First, the temperature is increased from room temperature to 120℃ over 20 minutes and held for 1 hour; then the temperature is increased to 200℃ over 20 minutes and held for 2 hours; finally, the temperature is cooled to room temperature in the furnace.

[0029] Tin whisker modification: Take 10g of tin whiskers, ultrasonically clean them in ethanol solution for 30min to remove surface impurities, and then dry them in an oven at 80℃ for 2h. Add the dried and cleaned tin whiskers to an ethanol-water solution (volume ratio 1:1) containing silane coupling agent KH570 (silane coupling agent concentration 5wt%), and stir the reaction at 60℃ for 2h. After the reaction is complete, filter and collect the modified tin whiskers, wash them three times with ethanol, and vacuum dry them at 100℃ for 4h for later use.

[0030] Example 1 Weigh 55g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 323g. Add 10g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0031] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtered layer using a spray coating method, with the coating thickness controlled within the range of 12-18 μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature, resulting in a copper-based bearing with a surface coating. The cross-section of this bearing is shown below. Figure 2 As shown, the same applies below.

[0032] Example 2 Weigh 50g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0033] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0034] Example 3 Weigh 45g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 313g. Add 20g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0035] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0036] Comparative Example 1 Weigh 50g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g (without any filler). The resulting mixed slurry is ultrasonically dispersed at 800W for 60min, followed by mechanical stirring at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0037] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0038] Comparative Example 2 Weigh 50g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 5g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0039] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0040] Comparative Example 3 Weigh 39g of PAI resin, 20g of graphite, and 26g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0041] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0042] Comparative Example 4 Weigh 60g of PAI resin, 10g of graphite, and 15g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0043] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0044] Comparative Example 5 Weigh 50g of PAI resin, 15g of graphite, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of flake aluminum powder to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0045] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0046] Comparative Example 6 Weigh 50g of PAI resin, 15g of graphite, and 20g of boron nitride, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of modified tin whiskers to the mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, then mechanically stir at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0047] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0048] Comparative Example 7 Weigh 50g of PAI resin, 15g of boron nitride, and 20g of molybdenum disulfide, add N-ethylpyrrolidone (NEP) solvent, and stir until homogeneous to obtain a mixed slurry with a total weight of 318g. Add 15g of modified tin whiskers to this mixed slurry. Ultrasonically disperse the resulting mixture at 800W for 60min, followed by mechanical stirring at 500r / min for 2h to obtain a uniform and stable composite slurry.

[0049] A composite slurry was applied to the surface of a copper-based bearing substrate with an aluminum-tin sputtering layer using a spraying method, with the coating thickness controlled within the range of 12~18μm. After coating, a gradient temperature curing process was used for curing, followed by natural cooling to room temperature to obtain a copper-based bearing with a surface coating.

[0050] Test case The coating samples of the above embodiments and comparative examples were subjected to performance tests. Thermal conductivity was determined using the laser flare method (LFA); the coefficient of friction was tested on a multi-functional tribological testing machine, with a 42CrMo steel ring as the mating part, a load of 100-1000N, a sliding speed of 0-1m / s, and boundary oil lubrication conditions. The test results are summarized in Table 1.

[0051] Table 1 Performance Test Results Case Thermal conductivity of the coating (W / (m·K)) Coating friction coefficient Example 1 2.0 0.020 Example 2 3.5 0.015 Example 3 3.6 0.018 Comparative Example 1 0.7 0.036 Comparative Example 2 0.9 0.033 Comparative Example 3 3.0 0.025 Comparative Example 4 1.9 0.038 Comparative Example 5 3.3 0.030 Comparative Example 6 3.0 0.027 Comparative Example 7 2.8 0.025 The cross-sectional morphology of the copper-based bearings with surface coatings prepared in each embodiment was observed. The microstructures of the cross-sections of the samples from Examples 1, 2, and 3 are as follows: Figure 3 , Figure 4 and Figure 5 As shown. From Figures 3 to 5 As can be seen, the interface between the polymer coating, the aluminum-tin physical sputtering layer and the copper-based alloy layer is tightly bonded, and the modified tin whiskers and solid lubricant exhibit good dispersion characteristics in the resin matrix.

[0052] As shown in Table 1, the copper-based bearings with surface coatings prepared in Examples 1-3 of this invention achieved excellent test results in terms of thermal conductivity and coefficient of friction. Specifically, the thermal conductivity of the coatings in Examples 1-3 reached 2.0-3.6 W / (m·K), and the coefficient of friction under boundary oil lubrication conditions was as low as 0.015-0.020, exhibiting excellent thermal conductivity and heat dissipation performance as well as friction reduction and self-lubricating properties. Among them, Example 2 showed the most outstanding overall performance, with a thermal conductivity as high as 3.5 W / (m·K) and a coefficient of friction of only 0.015.

[0053] Comparative Example 1, without any modified tin whiskers, had a coating thermal conductivity of only 0.7 W / (m·K) and a friction coefficient as high as 0.036. Comparative Example 2, although it added 5g of modified tin whiskers, had only a small amount, resulting in limited improvement in both thermal conductivity (0.9 W / (m·K)) and friction coefficient (0.033). In contrast, Example 2, after adding 15g of modified tin whiskers, showed a significant increase in thermal conductivity to 3.5 W / (m·K) and a substantial decrease in friction coefficient to 0.015. This demonstrates that introducing a reasonable amount of modified tin whiskers into the coating is crucial for achieving both high thermal conductivity and an ultra-low friction coefficient. When the content of modified tin whiskers is too low, an effective thermal conductivity network cannot be constructed in the resin matrix, nor can sufficient solid lubrication synergy be provided; only when its content reaches the reasonable range of this invention can a qualitative leap in performance be achieved.

[0054] Comparative Example 3 reduced the PAI resin content and increased the amounts of graphite and molybdenum disulfide, resulting in an increase in the coating friction coefficient to 0.025 and a decrease in thermal conductivity. Comparative Example 4 added a large amount of PAI resin and correspondingly reduced the amounts of graphite and molybdenum disulfide, resulting in a significant deterioration in the friction coefficient to 0.038 and a decrease in thermal conductivity to 1.9 W / (m·K). It can be seen that in the coating system of this invention, a reasonable ratio must be maintained between the base resin PAI and the graphite and molybdenum disulfide. Too little resin matrix will result in the filler not being completely coated, leading to poor coating density and increased susceptibility to defects, thereby impairing thermal conductivity and lubrication performance. Conversely, too much resin matrix will excessively dilute the concentration of the functional filler, preventing the formation of a continuous and effective lubricating film and heat conduction pathway on the friction pair surface.

[0055] Comparative Example 5 used the same mass of flake aluminum powder instead of the modified tin whiskers of the present invention. Although its coating thermal conductivity reached 3.3 W / (m·K), its coefficient of friction increased significantly to 0.030, which was significantly worse than 0.015 in Example 2. This demonstrates that the modified tin whiskers with specific morphology used in the system of the present invention have an irreplaceable and unique role. One-dimensional whisker-shaped tin not only better cross-links with layered graphite and molybdenum disulfide in the coating to form a highly efficient three-dimensional heat conduction network, but also, during the high-pressure friction process of boundary lubrication, the tin whiskers, due to their low shear strength, more easily undergo synergistic rheological changes with graphite and molybdenum disulfide, forming a more uniform and more adhesive composite solid lubrication transfer film on the substrate surface. This achieves a perfect balance between high thermal conductivity and ultra-low friction, an effect that cannot be achieved using flake aluminum powder.

[0056] Comparative Example 6 used boron nitride instead of molybdenum disulfide, and Comparative Example 7 used boron nitride instead of graphite. The results showed that their thermal conductivity decreased to 3.0 W / (m·K) and 2.8 W / (m·K), respectively, while their friction coefficients increased to 0.027 and 0.025, respectively, both significantly inferior to Example 2. This indicates that although boron nitride also possesses certain lubrication and thermal conductivity capabilities, it does not exhibit good compatibility and synergy with the modified tin whiskers in the system of this invention. This invention requires the simultaneous use of appropriate amounts of graphite and molybdenum disulfide for compounding. Graphite and molybdenum disulfide exhibit unique physicochemical complementarity in their layered crystal structure, interlayer shear characteristics, and geometric network construction with one-dimensional modified tin whiskers.

[0057] In summary, through the above comparative analyses, it can be concluded that in the PAI-based coating of this invention, the appropriate content of modified tin whiskers combined with appropriate contents of graphite and molybdenum disulfide are key to achieving excellent comprehensive performance. The components mutually promote and synergistically optimize each other through crystal morphology, spatial network construction, and physicochemical complementarity under boundary friction conditions, achieving an excellent balance between high thermal conductivity and ultra-low friction coefficient.

[0058] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A sliding bearing, characterized in that, The bearing includes a bearing substrate and a surface protective coating disposed on the surface of the bearing substrate, the surface protective coating being prepared from raw materials including polyamide-imide resin, modified tin whiskers, graphite and molybdenum disulfide.

2. The sliding bearing according to claim 1, characterized in that, The raw materials for the surface protective coating include the following components in parts by weight: Polyamide-imide resin: 45-55 parts; Modified tin whiskers: 10-20 parts; Graphite: 10-20 parts; Molybdenum disulfide: 15-25 parts.

3. The sliding bearing according to claim 1, characterized in that, The modified tin whiskers have a diameter of 1~5μm and an aspect ratio of 10~50.

4. The sliding bearing according to claim 1, characterized in that, The modified tin whiskers are tin whiskers modified with silane coupling agent KH570.

5. The sliding bearing according to claim 1, characterized in that, The bearing substrate is a copper-based bearing substrate with an aluminum-tin sputtering layer, and the surface protective coating is disposed on the surface of the aluminum-tin sputtering layer.

6. A method for preparing a sliding bearing as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step S1: Disperse polyamide-imide resin, graphite, molybdenum disulfide and modified tin whiskers in a solvent to obtain a composite slurry; Step S2: Apply the composite slurry to the surface of the bearing substrate to form a coating; Step S3: Curing the coating to obtain the sliding bearing.

7. The preparation method according to claim 6, characterized in that, Before step S1, the method further includes a step of modifying tin whiskers: placing the tin whiskers in a solution containing a silane coupling agent for surface treatment to obtain the modified tin whiskers; in step S1, the components are dispersed evenly by a combination of ultrasonic dispersion and mechanical stirring; wherein, the ultrasonic power is 600~1000W and the time is 30~90min; the mechanical stirring speed is 300~800r / min and the time is 1~3h.

8. The preparation method according to claim 6, characterized in that, In step S2, the composite slurry is coated onto the surface of the bearing substrate by spraying; the bearing substrate is a copper-based bearing substrate with an aluminum-tin sputtering layer.

9. The preparation method according to claim 6, characterized in that, In step S3, the curing process is a gradient temperature curing process: first, the temperature is raised from room temperature to 120°C and held for 0.5 to 2 hours, then the temperature is raised to 200°C and held for 1 to 3 hours, and finally the temperature is cooled to room temperature.

10. The application of the sliding bearing according to any one of claims 1 to 5 or the sliding bearing prepared by the method according to any one of claims 6 to 9, characterized in that, Used for main bearings, connecting rod bearings, or bushings in engines.

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