Preparation process of wear-resistant coating for bicycle spokes

Abstract

The invention discloses a preparation process of a wear-resistant coating for bicycle spokes, and belongs to the technical field of surface treatment of bicycle parts. The process comprises the steps of base material pretreatment, transition layer preparation, gradient wear-resistant coating preparation and post-treatment and detection. Basic oil removal, sand blasting coarsening and acid pickling activation are sequentially carried out on the base material pretreatment; the transition layer is prepared through chemical plating, a plating solution comprises nickel sulfate hexahydrate and other components, and plating is conducted for 30-40 minutes at the temperature of 85 DEG C; the gradient wear-resistant coating is prepared by preparing composite sol containing aluminum nitrate nonahydrate, tetrabutyl titanate, nano SiC dispersion liquid and graphene suspension, coating and drying, and sintering by using a 1.5 kW industrial microwave oven under the protection of nitrogen according to a specific curve. And finally, post-treatment and detection are conducted, and it is ensured that the total thickness of the coating ranges from 11 micrometers to 17 micrometers, and the surface hardness is larger than or equal to HV1600. The wear-resistant coating prepared by the process is firm in combination and excellent in wear resistance, the process is environment-friendly, stable and controllable, the service life of the bicycle spoke can be remarkably prolonged, and the wear-resistant coating has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of spoke surface treatment technology, and more specifically, relates to a process for preparing a wear-resistant coating for bicycle spokes. Background Technology

[0002] As a crucial component connecting the hub and rim, bicycle spokes must withstand frequent tension, torque, and friction from contact with the hub and rim during riding. Currently, bicycle spokes are mostly made of high-carbon steel, and their surface is usually only treated with simple electroplating, such as chrome plating. However, this traditional treatment method has the problem of insufficient wear resistance. Over long-term use, the spoke surface is easily worn down by friction, which not only affects the appearance of the bicycle but may also lead to a decrease in spoke strength, posing a safety hazard.

[0003] Furthermore, traditional electroplating processes suffer from significant environmental pollution and high energy consumption, failing to align with the modern trend of green manufacturing. Therefore, developing a surface treatment process for bicycle spokes that offers excellent wear resistance, is environmentally friendly, and provides stable performance is of great practical importance. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a process for preparing a wear-resistant coating for bicycle spokes. The wear-resistant coating prepared by this process can significantly improve the wear resistance of bicycle spokes, extend their service life, and the process is environmentally friendly, stable and controllable.

[0005] To achieve the above-mentioned technical objectives, this invention discloses a process for preparing a wear-resistant coating for bicycle spokes, comprising: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening and pickling activation in sequence; Step b. Transition layer preparation: Prepare the chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 30-40 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes. Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry, and microwave sinter. The raw materials for the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion, and 0.1 g / L graphene suspension. The preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol (volume ratio of ethanol to tetrabutyl titanate is 1:1), adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, then add the nano-SiC dispersion and graphene suspension. The liquid was ultrasonically dispersed at 500W for 30 minutes, and the viscosity of the sol was controlled at 65mPa·s. The coating was carried out by dip-coating at a speed of 50mm / min. The drying process involved placing the sol at room temperature for 10 minutes and then drying it at 80℃ for 20 minutes. The microwave sintering was carried out using a 1.5kW industrial microwave oven with a frequency of 2.45GHz and a nitrogen protection device. The nitrogen flow rate was 2L / min. The sintering curve was as follows: the temperature was increased to 200℃ at a rate of 50℃ / min and held for 10 minutes, then increased to 450℃ at a rate of 30℃ / min and held for 30 minutes, and finally cooled naturally to below 100℃. Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 11-17μm, the surface hardness is ≥HV1600, the cross-cut test grade is ≤1, and the edge peeling area is <5%.

[0006] According to one embodiment of the present invention, in step a above, alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned for 20 minutes at 60°C with an ultrasonic power of 300W, and then rinsed three times with deionized water; sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.4-0.5MPa, 100-mesh white corundum abrasive, maintaining a distance of 150mm between the gun and the spoke surface, a spray angle of 45°, and a spraying time of 30 seconds, resulting in a spoke surface roughness of Ra2.0-2.5μm after treatment; subsequently, it is blown with compressed air and wiped clean with anhydrous ethanol; acid pickling activation uses an 8% hydrochloric acid solution, immersing the spokes at room temperature for 30 seconds, then rinsing with deionized water until the pH value is 6-7, and then drying in an 80°C oven for 10 minutes.

[0007] According to one embodiment of the present invention, in step b above, the nano-SiC dispersion accounts for 12% of the total mass of the sol; and the graphene suspension accounts for 0.3% of the total mass of the sol.

[0008] According to one embodiment of the present invention, the hardness of the white fused alumina is HV2200-2400.

[0009] According to one embodiment of the present invention, the transition layer is a Ni-P alloy layer with a phosphorus content of 8-10% and a hardness of HV450-500.

[0010] According to one embodiment of the present invention, a coating with a thickness of 8-12 μm can be obtained by a single coating in the preparation of the above-mentioned gradient wear-resistant coating.

[0011] Compared with the prior art, the present invention can achieve the following technical effects: This invention forms a firmly bonded, high-performance wear-resistant coating on the surface of bicycle spokes through steps including substrate pretreatment, transition layer preparation, gradient wear-resistant coating preparation, and post-treatment and testing. The transition layer enhances the adhesion between the coating and the substrate, while the gradient wear-resistant coating imparts excellent wear resistance to the spokes.

[0012] The use of electroless plating to prepare the transition layer is more environmentally friendly than traditional electroplating, reducing pollutant emissions. Furthermore, the electroless plating process is easier to control, ensuring the uniformity and stability of the transition layer.

[0013] The gradient wear-resistant coating is prepared using a composite sol-gel coating combined with microwave sintering. Nano-SiC and graphene are added to the composite sol. Nano-SiC significantly improves the coating's hardness and wear resistance, while graphene helps improve its toughness and crack resistance. The synergistic effect of these two components results in excellent overall coating performance. Microwave sintering, characterized by uniform heating, low energy consumption, and high efficiency, helps ensure coating quality.

[0014] The entire process is stable and controllable, and the resulting wear-resistant coating has a uniform thickness and reliable performance, which can significantly extend the service life of bicycle spokes and has good application prospects.

[0015] Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flow chart of the process for preparing the wear-resistant coating on bicycle spokes according to an embodiment of the present invention. Detailed Implementation

[0017] The following will describe in detail the implementation of the present invention with reference to the accompanying drawings and embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0018] Please refer to Figure 1 , Figure 1 This is a flow chart of the process for preparing the wear-resistant coating on bicycle spokes according to an embodiment of the present invention.

[0019] This invention discloses a process for preparing a wear-resistant coating for bicycle spokes, comprising: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening, and acid pickling activation in sequence; alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned for 20 minutes at 60℃ with an ultrasonic power of 300W, and then rinsed three times with deionized water; sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.4-0.5MPa, 100-mesh white corundum abrasive, a distance of 150mm between the gun and the spoke surface, a spray angle of 45°, and a spraying time of 30 seconds. After treatment, the surface roughness of the spoke reaches Ra2.0-2.5μm. Then, it is blown with compressed air and wiped clean with anhydrous ethanol; acid pickling activation uses an 8% hydrochloric acid solution, immersing the spoke at room temperature for 30 seconds, then rinsing with deionized water until the pH value is 6-7, and then drying in an 80℃ oven for 10 minutes.

[0020] Step b. Transition layer preparation: Prepare the chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 30-40 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes. Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry, and microwave sinter. The raw materials for the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion, and 0.1 g / L graphene suspension. The preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol (volume ratio of ethanol to tetrabutyl titanate is 1:1), adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, then add the nano-SiC dispersion and graphene suspension. The liquid was ultrasonically dispersed at 500W for 30 minutes, and the viscosity of the sol was controlled at 65mPa·s. The coating was carried out by dip-coating at a speed of 50mm / min. The drying process involved placing the sol at room temperature for 10 minutes and then drying it at 80℃ for 20 minutes. The microwave sintering was carried out using a 1.5kW industrial microwave oven with a frequency of 2.45GHz and a nitrogen protection device. The nitrogen flow rate was 2L / min. The sintering curve was as follows: the temperature was increased to 200℃ at a rate of 50℃ / min and held for 10 minutes, then increased to 450℃ at a rate of 30℃ / min and held for 30 minutes, and finally cooled naturally to below 100℃. Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 11-17μm, the surface hardness is ≥HV1600, the cross-cut test grade is ≤1, and the edge peeling area is <5%. Example 1

[0021] A process for preparing an abrasion-resistant coating for bicycle spokes includes the following steps: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening, and acid pickling activation in sequence; alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned for 20 minutes at 60℃ with an ultrasonic power of 300W, and then rinsed three times with deionized water; sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.4MPa and 100-mesh white corundum (hardness HV2200) abrasive, maintaining a distance of 150mm between the gun and the spoke surface, a spray angle of 45°, and a spraying time of 30 seconds, after which the surface roughness of the spoke reaches Ra2.0μm, followed by blowing with compressed air and wiping with anhydrous ethanol for cleaning; acid pickling activation uses an 8% hydrochloric acid solution, immersing the spoke at room temperature for 30 seconds, then rinsing with deionized water until the pH value is 6, and then drying in an 80℃ oven for 10 minutes.

[0022] Step b. Transition layer preparation: Prepare a chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 30 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes; the resulting transition layer is a Ni-P alloy layer with a phosphorus content of 8% and a hardness of HV450.

[0023] Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry, and microwave sinter it; the raw materials of the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion (accounting for 12% of the total mass of the sol), and 0.1 g / L graphene suspension (accounting for 0.3% of the total mass of the sol); the preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol dropwise, wherein the volume ratio of ethanol to tetrabutyl titanate is 1:1, adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, then add nano-SiC dispersion and The graphene suspension was ultrasonically dispersed at 500W for 30 minutes, controlling the sol viscosity at 65mPa·s. Coating was performed using the dip-coating method at a speed of 50mm / min, achieving an 8μm thick coating in a single coat. Drying involved first placing the coating at room temperature for 10 minutes, followed by drying at 80℃ for 20 minutes. Microwave sintering was performed using a 1.5kW industrial microwave oven with a frequency of 2.45GHz, equipped with a nitrogen protection device and a nitrogen flow rate of 2L / min. The sintering curve involved heating to 200℃ at a rate of 50℃ / min and holding for 10 minutes, then heating to 450℃ at a rate of 30℃ / min and holding for 30 minutes, and finally naturally cooling to below 100℃.

[0024] Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 11μm, the surface hardness is HV1600, the cross-cut test grade is 1, and the edge peeling area is 3%. Example 2

[0025] A process for preparing an abrasion-resistant coating for bicycle spokes includes the following steps: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening, and acid pickling activation in sequence; alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned for 20 minutes at 60℃ with an ultrasonic power of 300W, and then rinsed three times with deionized water; sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.45MPa and 100-mesh white corundum (hardness HV2300) abrasive, maintaining a distance of 150mm between the gun and the spoke surface, a spray angle of 45°, and a spraying time of 30 seconds, after which the surface roughness of the spoke reaches Ra2.3μm, followed by blowing with compressed air and wiping with anhydrous ethanol for cleaning; acid pickling activation uses an 8% hydrochloric acid solution, immersing the spoke at room temperature for 30 seconds, then rinsing with deionized water until the pH value is 6.5, and then drying in an 80℃ oven for 10 minutes.

[0026] Step b. Transition layer preparation: Prepare a chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 35 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes; the resulting transition layer is a Ni-P alloy layer with a phosphorus content of 9% and a hardness of HV480.

[0027] Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry, and microwave sinter it; the raw materials of the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion (accounting for 12% of the total mass of the sol), and 0.1 g / L graphene suspension (accounting for 0.3% of the total mass of the sol); the preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol dropwise, wherein the volume ratio of ethanol to tetrabutyl titanate is 1:1, adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, then add nano-SiC dispersion and The graphene suspension was ultrasonically dispersed at 500W for 30 minutes, controlling the sol viscosity at 65mPa·s. Coating was performed using the dip-coating method at a speed of 50mm / min, achieving a 10μm thick coating in a single coat. Drying involved first placing the coating at room temperature for 10 minutes, followed by drying at 80℃ for 20 minutes. Microwave sintering was performed using a 1.5kW industrial microwave oven with a frequency of 2.45GHz, equipped with a nitrogen protection device and a nitrogen flow rate of 2L / min. The sintering curve involved heating to 200℃ at a rate of 50℃ / min and holding for 10 minutes, then heating to 450℃ at a rate of 30℃ / min and holding for 30 minutes, and finally naturally cooling to below 100℃.

[0028] Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 14μm, the surface hardness is HV1700, the cross-cut test grade is 0, and the edge peeling area is 1%. Example 3

[0029] A process for preparing an abrasion-resistant coating for bicycle spokes includes the following steps: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening, and acid pickling activation in sequence; alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned at 60℃ for 20 minutes with an ultrasonic power of 300W, and then rinsed three times with deionized water; sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.5MPa and 100-mesh white corundum (hardness HV2400) abrasive, the distance between the gun and the spoke surface is maintained at 150mm, the spray angle is 45°, and the spraying time is 30 seconds. After treatment, the surface roughness of the spoke reaches Ra2.5μm. Then it is blown with compressed air and wiped clean with anhydrous ethanol; acid pickling activation uses an 8% hydrochloric acid solution, the spoke is immersed in room temperature for 30 seconds, then rinsed with deionized water until the pH value is 7, and then dried in an 80℃ oven for 10 minutes.

[0030] Step b. Transition layer preparation: Prepare a chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 40 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes; the resulting transition layer is a Ni-P alloy layer with a phosphorus content of 10% and a hardness of HV500.

[0031] Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry, and microwave sinter it; the raw materials of the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion (accounting for 12% of the total mass of the sol), and 0.1 g / L graphene suspension (accounting for 0.3% of the total mass of the sol); the preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol dropwise, wherein the volume ratio of ethanol to tetrabutyl titanate is 1:1, adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, then add nano-SiC dispersion and The graphene suspension was ultrasonically dispersed at 500W for 30 minutes, controlling the sol viscosity at 65mPa·s. Coating was performed using the dip-coating method at a speed of 50mm / min, achieving a 12μm thick coating in a single coat. Drying involved first placing the coating at room temperature for 10 minutes, followed by drying at 80℃ for 20 minutes. Microwave sintering was performed using a 1.5kW industrial microwave oven with a frequency of 2.45GHz, equipped with a nitrogen protection device and a nitrogen flow rate of 2L / min. The sintering curve involved heating to 200℃ at a rate of 50℃ / min and holding for 10 minutes, then heating to 450℃ at a rate of 30℃ / min and holding for 30 minutes, and finally naturally cooling to below 100℃.

[0032] Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 17μm, the surface hardness is HV1800, the cross-cut test grade is 0, and the edge peeling area is 0%.

[0033] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A process for preparing a wear-resistant coating for bicycle spokes, characterized in that, include: Step a. Substrate pretreatment: The spoke body made of high carbon steel is subjected to alkaline degreasing, sandblasting roughening and pickling activation in sequence; Step b. Transition layer preparation: Prepare a chemical plating solution and perform plating; the chemical plating solution contains 25 g / L nickel sulfate hexahydrate, 20 g / L sodium hypophosphite monohydrate, 15 g / L trisodium citrate, 10 g / L ammonium chloride, and 0.5 mg / L lead nitrate, with the remainder diluted with deionized water; the plating temperature is controlled at 85℃, using a water bath for heating, with a temperature difference not exceeding ±1℃, and the plating time is 30-40 minutes. During the plating process, mechanical stirring is performed at a stirring speed of 100 r / min. After plating, rinse with deionized water and then dry in a 120℃ oven for 20 minutes. Step c. Preparation of gradient wear-resistant coating: Prepare a composite sol, then coat, dry and microwave sinter; the raw materials of the composite sol include 0.6 mol / L aluminum nitrate nonahydrate, 0.2 mol / L tetrabutyl titanate, 50 g / L nano-SiC dispersion, and 0.1 g / L graphene suspension; the preparation steps of the composite sol are as follows: dissolve aluminum nitrate nonahydrate in deionized water at 80℃ for 2 hours, add tetrabutyl titanate diluted with ethanol, wherein the volume ratio of ethanol to tetrabutyl titanate is 1:1, adjust the pH to 2.0 with hydrochloric acid and stir for 1 hour, add nano-SiC dispersion and graphene suspension, and ultrasonically disperse at 500W power for 30 minutes, controlling the sol viscosity at 65 mPa·s; coating is carried out by dip-coating method, and the coating speed is 50 mm / min; drying is carried out by first placing at room temperature for 10 minutes, and then drying at 80℃ for 20 minutes. The microwave sintering uses a 1.5kW industrial microwave oven with a frequency of 2.45GHz, equipped with a nitrogen protection device, and a nitrogen flow rate of 2L / min. The sintering curve is as follows: heat up to 200℃ at a rate of 50℃ / min and hold for 10 minutes, then heat up to 450℃ at a rate of 30℃ / min and hold for 30 minutes, and finally cool naturally to below 100℃. Step d. Post-processing and inspection: Remove burrs from the edges of the coating at both ends of the spokes with 1000-grit sandpaper, ultrasonically clean with anhydrous ethanol for 5 minutes, and check that the total thickness of the gradient wear-resistant coating and the transition layer reaches 11-17μm, the surface hardness is ≥HV1600, the cross-cut test grade is ≤1, and the edge peeling area is <5%.

2. The process for preparing a wear-resistant coating for bicycle spokes according to claim 1, characterized in that, In step a, alkaline degreasing uses a 5% sodium hydroxide solution containing 0.5% sodium dodecyl sulfate, ultrasonically cleaned for 20 minutes at 60°C with an ultrasonic power of 300W, and then rinsed three times with deionized water. Sandblasting roughening uses a pressure-type sandblasting gun with a working pressure of 0.4-0.5MPa, using 100-mesh white corundum abrasive. The distance between the gun and the spoke surface is maintained at 150mm, the spray angle is 45°, and the spraying time is 30 seconds. After treatment, the spoke surface roughness reaches Ra2.0-2.5μm. It is then blew with compressed air and wiped clean with anhydrous ethanol. Acid pickling activation uses an 8% hydrochloric acid solution, immersing the spokes at room temperature for 30 seconds, then rinsing with deionized water until the pH value reaches 6-7, and finally drying in an 80°C oven for 10 minutes.

3. The process for preparing a wear-resistant coating for bicycle spokes according to claim 1, characterized in that, In step b, the nano-SiC dispersion accounts for 12% of the total mass of the sol; the graphene suspension accounts for 0.3% of the total mass of the sol.

4. The process for preparing a wear-resistant coating for bicycle spokes according to claim 1, characterized in that, The hardness of the white fused alumina is HV2200-2400.

5. The process for preparing a wear-resistant coating for bicycle spokes according to claim 1, characterized in that, The transition layer is a Ni-P alloy layer with a phosphorus content of 8-10% and a hardness of HV450-500.

6. The process for preparing a wear-resistant coating for bicycle spokes according to claim 1, characterized in that, In the preparation of the gradient wear-resistant coating, a single coating can achieve a thickness of 8-12 μm.

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