A PEEK-based superlubricant composite material, preparation method and application

Abstract

The present invention relates to the technical field of superlubricant friction and wear, and particularly to a PEEK-based superlubricant composite material, a preparation method and an application, including: performing surface texturing treatment on a PEEK workpiece and removing the heat-affected zone around the surface texture of the PEEK workpiece; preparing a fluoropolymer coating on the surface of the PEEK workpiece to cover the surface texture of the PEEK workpiece; drying and sintering the PEEK workpiece coated with the fluoropolymer coating to obtain a PEEK-based superlubricant composite material; wherein, the lubricating medium of the PEEK-based superlubricant composite material is pure glycerol. Through the synergistic effect of the surface texturing technology and the fluoropolymer coating, the present invention gives full play to the lubricating effect of the coating and the texture storage function, enabling PEEK to achieve stable superlubrication in one step under an atmospheric environment. It solves the problem in the prior art that the high friction coefficient of PEEK material results in the inability of PEEK material to achieve long-life stable superlubrication.

Description

Technical Field

[0001] The present invention relates to the technical field of superlubricant friction and wear, and specifically to a PEEK-based superlubricant composite material, a preparation method and an application thereof. Background Art

[0002] PEEK (polyetheretherketone) resin is a semi-crystalline thermoplastic with a unique molecular structure. Due to its excellent properties such as high strength, high temperature resistance, low density, and easy manufacturability, it has a wide range of applications in the fields of machinery, aerospace, military equipment, electronics, etc., and is expected to become a substitute for traditional metals. However, the original PEEK has a relatively high friction coefficient (about 0.3) and poor wear resistance, resulting in a low service life of PEEK. Therefore, further reducing friction and wear is one of the core issues for extending the service life of PEEK workpieces. The use of superlubrication technology can minimize energy loss by reducing friction to an extremely low level, thereby extending the service life of equipment. Superlubrication refers to a state where the friction coefficient between two sliding surfaces is close to zero, that is, the coefficient of friction COF < 0.01.

[0003] Currently, methods such as inorganic filler modification (such as graphite, MoS2) and polymer blending (such as polytetrafluoroethylene, PTFE) are often used to prepare PEEK composite materials to improve their tribological properties. CN112812497 discloses a highly lubricious PEEK material, its preparation method and injection molding process. By melting and granulating PEEK, polytetrafluoroethylene and molybdenum disulfide, a high-performance PEEK material is obtained, and the friction coefficient of the prepared PEEK material is reduced to 0.145. CN114181493 discloses a PEEK-based composite material with low wear and high comprehensive performance and its preparation method. By uniformly mixing PEEK with PTFE, a modified lubricant and polybenzimidazole (PBI) and putting them into a twin-screw extruder, a PEEK-based composite material is obtained. The friction coefficient of the modified PEEK composite material is reduced to about 0.15. Although the friction performance of the PEEK composite material modified by the above methods has been improved, the friction coefficient of the PEEK composite material is still very high, and it cannot reach the superlubrication state, making it difficult to completely solve the PEEK friction and wear problem. Summary of the Invention

[0004] Aiming at the problem that the PEEK material has a high friction factor in the prior art, resulting in the inability of the PEEK material to achieve long-life stable superlubrication, the present invention provides a PEEK-based superlubricant composite material, a preparation method and an application thereof.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing a PEEK-based superlubricant composite material, comprising:

[0007] Performing surface texturing on the PEEK workpiece and removing the heat-affected zone around the surface texture of the PEEK workpiece;

[0008] Preparing a fluoropolymer coating on the surface of the PEEK workpiece to cover the surface texture of the PEEK workpiece;

[0009] Drying and sintering the PEEK workpiece coated with the fluoropolymer coating to obtain a PEEK-based superlubricant composite material; wherein, the lubricating medium of the PEEK-based superlubricant composite material is pure glycerol.

[0010] Further, the surface texturing of the PEEK workpiece is performed by means of template replication, electro-discharge machining or laser machining.

[0011] Further, the method for removing the heat-affected zone around the surface texture of the PEEK workpiece is: after performing surface texturing on the PEEK workpiece, polishing the surface of the PEEK workpiece with 2000# - 4000# sandpaper to remove the heat-affected zone around the texture.

[0012] Further, the maximum diameter of the surface texture of the PEEK workpiece is 50 - 200 μm, the maximum depth of the texture is 5 - 100 μm, and the areal density of the texture is 5% - 35%.

[0013] Further, the method for preparing the fluoropolymer coating on the surface of the PEEK workpiece is:

[0014] Mixing the fluoropolymer and the PAI solution evenly to obtain a fluoropolymer coating solution;

[0015] Coating the fluoropolymer coating solution on the surface of the PEEK workpiece by spraying, spin-coating or drop-coating, so that the fluoropolymer coating solution covers the texture surface of the PEEK workpiece.

[0016] Further, the fluoropolymer is one or more of soluble polytetrafluoroethylene, polytetrafluoroethylene and perfluorinated ethylene.

[0017] Further, the mass ratio of the fluoropolymer to the PAI solution ≥ 0.75, and the concentration of the PAI solution is 0.09 - 0.1 g / mL.

[0018] Further, during the drying and sintering process of the PEEK workpiece coated with the fluoropolymer coating, the drying condition is 100°C - 120°C, and the sintering temperature is 250°C - 280°C.

[0019] The present invention provides a PEEK-based superlubricant composite material prepared by the above method.

[0020] As described above, in the application of the above-mentioned superlubricant composite material in the field of mechanical engineering, the lubricating medium is pure glycerol.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the present invention, the surface texturing treatment of PEEK can increase the specific surface area of the matrix, and the surface of the PEEK workpiece after the surface texturing treatment can better store lubricating substances, enhancing the bonding force between the solid lubricating coating and the PEEK workpiece, and can significantly improve the service life of the coating. The PEEK-based composite material prepared by this method can not only achieve macroscopic superlubrication and long service life, but also has the advantages of simple preparation process and stable performance, and has good application prospects in actual industrial applications.

[0023] In the present invention, the fluoropolymer coating is a water-based coating, and the preparation process is simple and easy to operate. Using water as a solvent saves a large amount of resources, and has the advantages of non-toxic and pollution-free.

[0024] In the present invention, the method of solid-liquid composite superlubrication is adopted, so that the PEEK material can achieve macroscopic one-step superlubrication in the atmospheric environment without a running-in period.

[0025] The present invention also provides a PEEK-based superlubricant composite material prepared by the above method. The composite material involves two parts: a textured surface and a fluoropolymer coating, and can not only achieve macroscopic superlubrication and long service life.

[0026] As described above, the application of the superlubricant composite material in the field of mechanical engineering. The mechanical parts prepared by using this superlubricant composite material have better stability and longer service life, and have better safety performance and economic benefits. Brief Description of the Drawings

[0027] Figure 1 It is a flowchart of a preparation method of a PEEK-based superlubricant composite material of the present invention.

[0028] Figure 2 It is a surface optical picture of a PEEK-based superlubricant composite material of the present invention.

[0029] Figure 3 It is a curve graph of the surface friction test result of the PEEK-based superlubricant composite material prepared in Example 1 of the present application.

[0030] Figure 4 It is a curve graph of the surface dry friction test result of the PEEK-based superlubricant composite material prepared in Example 3 of the present application.

[0031] Figure 5 It is a curve graph of the surface friction test result of the PEEK-based superlubricant composite material prepared in Comparative Example 1 of the present application.

[0032] Figure 6 It is the surface friction test result curve graph of the PEEK-based superlubricating composite material prepared in Comparative Example 3 of this application. Specific embodiments

[0033] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] It should be noted that in order to make the solid lubricant better combine with the binder, an appropriate amount of dispersant and other additives can be added. This is a conventional expansion of the innovative idea of the present invention and should be within the protection scope of this application.

[0035] See Figure 1 , the present invention provides a preparation method of a PEEK-based superlubricating composite material, including:

[0036] S1: Perform surface texturing on the PEEK workpiece and remove the heat-affected zone around the surface texture of the PEEK workpiece. Specifically: Textures can be prepared on the surface of the PEEK workpiece by means of template replication, electroprocessing or laser processing; after performing surface texturing on the PEEK workpiece, polish the surface of the PEEK workpiece with 2000# - 4000# sandpaper to remove the heat-affected zone around the texture; the maximum diameter of the surface texture of the PEEK workpiece is 50 - 200 μm, the maximum depth of the texture is 5 - 100 μm, and the areal density of the texture is 5% - 35%;

[0037] S2: Prepare a fluoropolymer coating on the surface of the PEEK workpiece to cover the surface texture of the PEEK workpiece. Specifically: Mix the fluoropolymer and the PAI solution evenly to obtain a fluoropolymer coating material; the fluoropolymer is one or more of soluble polytetrafluoroethylene, polytetrafluoroethylene and polyperfluoroethylene; the mass ratio of the fluoropolymer to PAI ≥ 0.75, and the concentration of the PAI solution is 0.09 - 0.1 g / mL;

[0038] The fluoropolymer coating is applied to the surface of the PEEK workpiece by spraying, spin coating or drop coating, so that the fluoropolymer coating covers the textured surface of the PEEK workpiece;

[0039] S3: Dry and sinter the PEEK workpiece coated with the fluoropolymer coating to obtain a PEEK-based superlubricating composite material; wherein, the drying condition of the PEEK workpiece coated with the fluoropolymer coating is 100°C to 120°C, and the sintering temperature is 250°C to 280°C; the lubricating medium of the PEEK-based superlubricating composite material is pure glycerol.

[0040] Example 1:

[0041] A preparation method of a PEEK-based superlubricating composite material includes the following steps:

[0042] The PEEK workpiece is polished with 3000# sandpaper to make the surface of the workpiece flat and smooth; a circular texture is prepared on the polished PEEK workpiece surface using a laser marking machine, the texture diameter is 100 μm, the depth is 15 μm, and the areal density is 10%; the heat-affected zone around the texture is removed by polishing with 3000# sandpaper, and the PEEK workpiece is ultrasonically cleaned and placed in a drying oven for drying to obtain a textured PEEK workpiece, as Figure 2 shown, the textures are uniformly arranged, and the size and spacing conform to the set values.

[0043] 0.4 g of polyamide-imide (PAI) is respectively mixed with 0.1 g, 0.3 g, and 0.6 g of soluble polytetrafluoroethylene (PFA), and 4 g of distilled water is added. The mixed solution is ultrasonically treated for 10 min to obtain a solid lubricating coating.

[0044] The solid lubricating coating is applied to the surface of the surface-textured PEEK workpiece by the drop coating method, dried in a drying oven at 120°C, and then sintered in a high-temperature sintering furnace at 280°C for 120 min to obtain a PEEK-based composite material.

[0045] The prepared PEEK-based composite material is subjected to a friction experiment to test its friction performance. The prepared PEEK-based composite material workpiece is placed on a friction and wear testing machine for a friction experiment. The test conditions are: using pure glycerol as the lubricant, applying a load of 5 N, a frequency of 9 Hz, a stroke of 1 mm, and performing the friction experiment at room temperature.

[0046] The friction data is as Figure 3 shown, the PEEK-based PFA solid lubricating coatings with different concentrations can all achieve one-step superlubrication in the atmospheric environment, the lowest friction coefficient is 0.007, and there is no running-in period.

[0047] Example 2:

[0048] A preparation method of a PEEK-based superlubricating composite material, comprising the following steps:

[0049] Sand the PEEK workpiece with 3000# sandpaper to make the surface of the workpiece flat and smooth; use a laser marking machine to prepare circular textures on the surface of the polished PEEK workpiece, with a texture diameter of 100 μm, a depth of 15 μm, and an area density of 15%; use 3000# sandpaper to grind off the heat-affected zone around the texture, and ultrasonically clean the PEEK workpiece and place it in a drying oven to dry, obtaining a PEEK workpiece with textures.

[0050] Mix 0.4 g of polyamide-imide (PAI) with 0.1 g, 0.3 g, and 0.6 g of polytetrafluoroethylene (PTFE) respectively, and add 4 g of distilled water. Ultrasonically treat the mixed solution for 10 min to obtain a solid lubricating coating.

[0051] Use the drop coating method to coat the solid lubricating coating on the surface of the PEEK workpiece after surface texturing treatment, place it in a drying oven and dry it at 120 °C, and then place it in a high-temperature sintering furnace and sinter it at 280 °C for 120 min to obtain a PEEK-based composite material.

[0052] Conduct a friction experiment on the prepared PEEK-based composite material to test its friction performance. Place the prepared PEEK-based composite material workpiece on a friction and wear testing machine to conduct a friction experiment. The test conditions are: using pure glycerol as the lubricant, applying a load of 5 N, a frequency of 9 Hz, a stroke of 1 mm, and conducting the friction experiment at room temperature.

[0053] When the PTFE content is higher than 60%, the PEEK-based solid lubricating coating containing PTFE can achieve one-step superlubrication in an atmospheric environment, with a friction coefficient of 0.009 and no running-in period.

[0054] Example 3:

[0055] A preparation method of a PEEK-based superlubricating composite material, the method comprising the following steps:

[0056] Sand the PEEK workpiece with 2000# sandpaper to make the surface of the workpiece flat and smooth; use a laser marking machine to prepare circular textures on the surface of the polished PEEK workpiece, with a texture diameter of 80 μm, a depth of 15 μm, and an area density of 10%; use 3000# sandpaper to grind off the heat-affected zone around the texture, and ultrasonically clean the PEEK workpiece and place it in a drying oven to dry, obtaining a PEEK workpiece with textures.

[0057] Put 0.4 g of polyamide-imide (PAI) and 0.8 g of polytetrafluoroethylene (PTFE) into a reagent bottle respectively, and then add 4 g of distilled water. Ultrasonically treat it for 10 min to obtain a solid lubricating coating.

[0058] The solid lubricant coating was applied to the surface of the PEEK workpiece after surface texturing treatment by the drop coating method, then placed in a drying oven and dried at 120 °C, and subsequently placed in a high-temperature sintering furnace and sintered at 280 °C for 120 min to obtain the PEEK-based composite material.

[0059] The friction experiment was carried out on the prepared PEEK-based composite material to test its friction performance. The prepared PEEK-based composite material workpiece was placed on a friction and wear testing machine for friction experiment. The test conditions were: dry friction, applying a load of 30 N, a frequency of 5 Hz, and a stroke of 3 mm, and the friction experiment was carried out at room temperature.

[0060] The friction data is as Figure 4 shown. The system can maintain a stable low friction coefficient for more than 4 h. The position where the friction coefficient suddenly increases indicates that the surface coating has been worn through and the lubricating substance inside the texture begins to take effect. It shows that the texture can play a role in storing the lubricating medium and increasing the system life.

[0061] Comparative Example 1:

[0062] To further illustrate the beneficial effects of the present invention, a PEEK-based composite material without a fluoropolymer coating was provided and its tribological behavior was tested, including the following steps:

[0063] The PEEK workpiece was polished with 2000# sandpaper to make the workpiece surface flat and smooth; a circular texture was prepared on the polished PEEK workpiece surface using a laser marking machine, with a texture diameter of 100 μm, a depth of 15 μm, and an area density of 10%; the heat-affected zone around the texture was removed by polishing with 3000# sandpaper, and the PEEK workpiece was ultrasonically cleaned and placed in a drying oven to dry, obtaining the PEEK workpiece with texture.

[0064] 0.4 g of polyamide-imide (PAI) was added to a reagent bottle, and then 4 g of distilled water was added, and it was ultrasonically treated for 10 min to obtain the solid lubricant coating.

[0065] The solid lubricant coating was applied to the surface of the PEEK workpiece by the drop coating method, placed in a drying oven and dried at 120 °C, and subsequently placed in a high-temperature sintering furnace and sintered at 280 °C for 120 min to obtain the PEEK-based composite material.

[0066] The friction experiment was carried out on the prepared PEEK-based composite material to test its friction performance. The prepared PEEK-based composite material workpiece was placed on a friction and wear testing machine for friction experiment. The test conditions were: using pure glycerol as the lubricant, applying a load of 5 N, a frequency of 9 Hz, and a stroke of 1 mm, and the friction experiment was carried out at room temperature.

[0067] See Figure 5 , the friction coefficient of this system is 0.06 and superlubrication cannot be achieved.

[0068] Comparative Example 2:

[0069] To further illustrate the beneficial effects of the present invention, a PEEK-based composite material without a fluoropolymer coating was provided, and its tribological behavior was tested, including the following steps:

[0070] The PEEK workpiece was polished with 2000# sandpaper to make the workpiece surface flat and smooth; a circular texture was prepared on the polished PEEK workpiece surface using a laser marking machine, with a texture diameter of 80 μm, a depth of 15 μm, and an area density of 20%; the heat-affected zone around the texture was removed by polishing with 3000# sandpaper, and the PEEK workpiece was ultrasonically cleaned and placed in a drying oven for drying to obtain a PEEK workpiece with a texture.

[0071] 0.4 g of polyamide-imide (PAI) and 0.4 g of graphite powder were added to a reagent bottle, and then 4 g of distilled water was added. It was ultrasonically treated for 10 min to obtain a solid lubricating coating.

[0072] The solid lubricating coating was applied to the surface of the workpiece of S2 by the drop coating method, dried in a drying oven at 120 °C, and then sintered in a high-temperature sintering furnace at 280 °C for 120 min to obtain a PEEK-based composite material.

[0073] The prepared material was subjected to a friction experiment to test its friction performance. The workpiece was placed on a friction and wear testing machine for a friction experiment. The test conditions were: using pure glycerol as a lubricant, applying a load of 5 N, a frequency of 9 Hz, a stroke of 1 mm, and conducting the friction experiment at room temperature.

[0074] The friction coefficient of this system was 0.045 - 0.055, and superlubrication could not be achieved.

[0075] Comparative Example 3:

[0076] To prove the beneficial effects of the present invention, a PEEK-based composite material without surface texturing treatment was provided, and its tribological behavior was tested, including the following steps:

[0077] 0.3 g of polyamide-imide (PAI) and 0.4 g of polytetrafluoroethylene (PTFE) were respectively added to a reagent bottle, and then 4 g of distilled water was added. It was ultrasonically treated for 10 min to obtain a solid lubricating coating.

[0078] The solid lubricating coating was applied to the surface of the PEEK-based workpiece by the drop coating method, dried in a drying oven at 120 °C, and then sintered in a high-temperature sintering furnace at 280 °C for 120 min to obtain a PEEK-based composite material.

[0079] The PEEK-based composite material was placed on a friction and wear testing machine for friction experiments. The test conditions were as follows: dry friction, an applied load of 30 N, a frequency of 5 Hz, a stroke of 3 mm, and the friction experiment was carried out at room temperature.

[0080] The friction data is as Figure 6 shown. It can be seen that when there is no texture, the coating is relatively easy to be worn through and the friction coefficient increases rapidly.

[0081] Such as the application of the above-mentioned superlubricant composite material in the field of mechanical engineering. The mechanical parts prepared by using this superlubricant composite material have better stability and longer service life, and have better safety performance and economic benefits.

[0082] In summary, the present invention provides a PEEK-based superlubricant composite material, a preparation method and an application. By setting textures on the surface of the PEEK workpiece, solid lubricants are stored in the textures, so as to achieve superlubrication on the surface of the PEEK workpiece while the textures provide continuous superlubrication for the surface of the PEEK workpiece; in addition, the setting of the textures can also capture the wear debris generated during the friction process, thereby minimizing abrasive wear, improving the surface microstructure by texturing the sample surface, thereby increasing the specific surface area of the substrate, providing a good attachment surface for the lubricating coating, and improving the bonding strength between the PEEK substrate and the coating.

[0083] The above are only the preferred embodiments of the present invention and are not used to limit the technical solutions of the present invention. Those skilled in the art should understand that without departing from the spirit and principles of the present invention, the technical solutions can be modified and replaced simply, and these modifications and replacements also fall within the protection scope covered by the claims.

Claims

1. A preparation method of a PEEK-based superlubricating composite material, characterized in that, Including: Performing surface texturing on the PEEK workpiece and removing the heat-affected zone around the surface texture of the PEEK workpiece; the maximum diameter of the surface texture of the PEEK workpiece is 50 - 200 μm, the maximum depth of the texture is 5 - 100 μm, and the areal density of the texture is 5% - 35%; Preparing a fluoropolymer coating on the surface of the PEEK workpiece to cover the surface texture of the PEEK workpiece; Drying and sintering the PEEK workpiece coated with the fluoropolymer coating to obtain a PEEK-based superlubricating composite material; wherein, the lubricating medium of the PEEK-based superlubricating composite material is pure glycerol.

2. The preparation method of the PEEK-based superlubricating composite material according to claim 1, characterized in that, Performing surface texturing on the PEEK workpiece by means of template replication, electroprocessing or laser processing.

3. The preparation method of the PEEK-based superlubricating composite material according to claim 1, wherein The method for removing the heat-affected zone around the surface texture of the PEEK workpiece is: after performing surface texturing on the PEEK workpiece, polishing the surface of the PEEK workpiece with 2000# - 4000# sandpaper to remove the heat-affected zone around the texture.

4. The preparation method of the PEEK-based superlubricating composite material according to claim 1, characterized in that, The method for preparing the fluoropolymer coating on the surface of the PEEK workpiece is: Mixing the fluoropolymer and the PAI solution evenly to obtain a fluoropolymer coating solution; Coating the fluoropolymer coating solution on the surface of the PEEK workpiece by spraying, spin coating or drop coating, so that the fluoropolymer coating solution covers the textured surface of the PEEK workpiece.

5. The preparation method of the PEEK-based superlubricant composite material according to claim 4, characterized in that, The fluoropolymer is one or more of soluble polytetrafluoroethylene, polytetrafluoroethylene and polyperfluoroethylene.

6. The preparation method of the PEEK-based superlubricating composite material according to claim 4, characterized in that, The mass ratio of the fluoropolymer to the PAI solution is ≥0.75, and the concentration of the PAI solution is 0.09 - 0.1 g / mL.

7. The preparation method of the PEEK-based superlubricating composite material according to claim 1, characterized in that, During the drying and sintering process of the PEEK workpiece coated with the fluoropolymer coating, the drying condition is 100°C - 120°C, and the sintering temperature is 250°C - 280°C.

8. A PEEK-based superlubricating composite material, characterized in that, Prepared by the method according to any one of claims 1 - 7.

9. The application of the superlubricating composite material as described in claim 8 in the field of mechanical engineering, characterized in that, The lubricating medium is pure glycerol.

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