Textured coating for sliding bearing and preparation method of textured coating

Abstract

The invention discloses a textured coating for a sliding bearing and a preparation method of the textured coating, and belongs to the technical field of plasma spraying coatings. The textured coating for the sliding bearing is prepared through the following steps: (1) carrying out laser pretreatment on bearing steel to obtain a textured matrix; (2) mixing a solvent, a binder, titanium nitride and titanium powder, and carrying out ball milling to obtain a suspension; and (3) the suspension liquid is sprayed to a textured base body in a plasma spraying mode, and the textured coating on the sliding bearing is obtained. The textured coating for the sliding bearing prepared by the invention has excellent hardness and friction resistance.

Description

Technical Field

[0001] This invention relates to the field of plasma spraying coating technology, specifically to a textured coating for sliding bearings and its preparation method. Background Technology

[0002] Roller cone drill bits are one of the most critical rock-breaking tools in oil and gas exploration and development, and their bearing system directly determines the service life and drilling efficiency of the drill bit. As the core load-bearing component of roller cone drill bits, sliding bearings operate under complex conditions such as low-speed heavy loads, strong impact vibrations, high temperature and pressure, and poor lubrication, resulting in significant friction and wear problems, which has become a major bottleneck restricting the improvement of roller cone drill bit lifespan. Existing technologies mostly improve service life by preparing wear-resistant coatings on the bearing surface. However, existing wear-resistant coatings still have certain shortcomings. Some high-hardness coatings are brittle and prone to cracking or peeling under strong impacts and alternating loads; some coatings have a high coefficient of friction under poor lubrication conditions, making it difficult to simultaneously achieve high strength, low friction, and wear resistance. Therefore, developing a coating with both high strength and high wear resistance to meet the service requirements of sliding bearings under complex oil and gas drilling conditions has significant engineering application value and practical significance for extending the service life of roller cone drill bits, improving drilling efficiency, and reducing operating costs.

[0003] Chinese invention patent CN119144953A discloses a method for preparing a composite coating for sliding bearings and the composite coating itself. The method includes: drying nickel-based underlayer alloy powder and copper-based alloy surface layer powder; aligning a cladding head with the area to be clad on the sliding bearing; based on first process parameters, uniformly feeding the nickel-based underlayer alloy powder onto the surface of the sliding bearing aligned with the cladding head using a scraper-type pressure powder feeder; melting the nickel-based underlayer alloy powder into droplets to form a micro-melt pool on the surface of the sliding bearing, and continuously cladding to form a nickel-based underlayer; after the sliding bearing with the nickel-based underlayer clad on its surface cools, polishing the nickel-based underlayer to a smooth surface; based on second process parameters, uniformly feeding copper-based alloy surface layer powder onto the surface of the nickel-based underlayer using a scraper-type pressure powder feeder; continuously cladding on the surface of the nickel-based underlayer to form a copper-based alloy surface layer, thereby obtaining a sliding bearing with a clad composite coating. However, its wear resistance needs improvement. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a textured coating for sliding bearings and a method for preparing the same.

[0005] A method for preparing a textured coating for sliding bearings includes the following steps: (1) The bearing steel is pretreated by laser to obtain a textured matrix; (2) The solvent, binder, titanium nitride and titanium powder are mixed and ball-milled to obtain a suspension; (3) The suspension is sprayed onto the textured substrate using plasma spraying to obtain a textured coating on the sliding bearing; The adhesive is prepared by the following method: S1: 4,4'-Diaminodiphenylmethane reacts with cyanuric chloride to produce intermediate 1, and the reaction equation is shown below: S2: Intermediate 1 reacts with LO-phosphoserine to generate intermediate 2, and the reaction equation is shown below: S3: Intermediate 2 reacts with 2-aminophenylboronic acid to form a binder; the reaction equation is shown below. In step S1, the molar ratio of 4,4'-diaminodiphenylmethane to cyanuric chloride is 1:(2.03-2.05).

[0006] In step S2, the molar ratio of intermediate 1 to LO-phosphoserine is 1:(2.04-2.06).

[0007] In step S3, the molar ratio of intermediate 2 to 2-aminophenylboronic acid is 1:(2.05-2.08).

[0008] In step (1), the scanning speed of the laser preprocessing is 80-100 mm / s and the repetition frequency is 25-30 kHz.

[0009] In step (1), the pulse width of the laser preprocessing is 5-10 ns.

[0010] In step (2), the ratio of solvent, binder, titanium nitride and titanium powder is 7:(0.1-0.15):(1.5-2):(1-1.5).

[0011] In step (3), the arc power of the plasma spraying is 70-90kW.

[0012] In step (3), the plasma spray gun moves at a speed of 200-300 mm / s.

[0013] A textured coating for sliding bearings is obtained by the above preparation method.

[0014] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The textured coating for sliding bearings prepared by this invention has excellent hardness and friction resistance. Attached Figure Description

[0015] Figure 1 The image shows the 1H NMR spectrum of the binder prepared in Example 1.

[0016] Figure 2 The image shows a high-resolution mass spectrum of the adhesive prepared in Example 1. Detailed Implementation

[0017] Example 1: Preparation of Adhesive S1: 300 ml of dichloromethane, 0.1 mol of 4,4'-diaminodiphenylmethane, and 0.203 mol of cyanuric chloride were added to a reaction vessel and stirred until homogeneous. 0.11 mol of potassium carbonate was added under ice bath conditions, and the reaction was carried out at 0°C for 4 h. After filtration, the mixture was distilled under reduced pressure at 30°C for 1 h. 200 ml of diethyl ether was added and stirred to precipitate the solid. After filtration, the solid was dried under vacuum at 40°C for 5 h to obtain intermediate 1. Its 1H NMR spectrum data are as follows: 1 HNMR (400 MHz, DMSO- d 6) δ 9.67 (s, 2H), 7.49 - 7.39 (m, 4H), 7.20-7.05 (m,4H), 3.87 (q, J = 1.0 Hz, 2H); HRMS (m / z): 494.9917[M+H] + ; S2: Add 300 ml of DMF and 0.1 mol of intermediate 1 to a reaction vessel, stir and mix well, add 200 ml of an aqueous solution containing 0.204 mol of LO-phosphoserine, adjust the pH to 11 with 10 wt% NaOH solution, heat to 40 °C, react for 7 h, cool to room temperature, add 200 ml of deionized water to dilute, adjust the pH to 4 with 1 M HCl solution, precipitate, filter, wash with deionized water (2 × 80 ml), and dry under vacuum at 60 °C for 12 h to obtain intermediate 2; its 1H NMR data are as follows: 1 H NMR (400 MHz, DMSO-) d 6) δ 12.49 (s, 2H), 9.75 (s, 2H), 7.72 - 7.61 (m, 2H), 7.49 -7.41 (m, 4H), 7.39 (s, 4H), 7.13 (dt, J = 7.5, 1.0 Hz, 4H), 4.69 - 4.52 (m,4H), 4.37 - 4.22 (m, 2H), 3.87 (q, J = 1.0 Hz, 2H); HRMS (m / z): 791.0591[M+H] + ; S3: Add 800 ml DMF, 0.1 mol intermediate 2, and 0.205 mol 2-aminophenylboronic acid to a reaction vessel, stir and mix well. Adjust the pH to 11 using 10 wt% NaOH solution, heat to 80℃, and react for 18 h. Cool to room temperature, add 1000 ml diethyl ether, stir to precipitate, filter, and wash successively with a mixed solution of 100 ml diethyl ether and anhydrous ethanol (volume ratio of diethyl ether to anhydrous ethanol is 1:1) and deionized water (2 × 80 ml). Dry under vacuum at 60℃ for 12 h to obtain the binder; its 1H NMR spectrum is shown below. Figure 1 As shown, the data is as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 12.49 (s, 2H), 8.91 (s, 2H), 8.71 (s, 2H), 7.87 - 7.76 (m, 2H), 7.69 (s, 4H), 7.48 - 7.41 (m, 4H), 7.41 - 7.35 (m, 6H), 7.25 - 7.18 (m, 2H), 7.13 (dt, J = 7.5, 1.0 Hz, 4H), 7.03 - 6.93 (m, 4H), 4.69 - 4.52 (m, 4H), 4.37 - 4.22 (m, 2H), 3.87 (p, J = 1.2 Hz, 2H); its high-resolution mass spectrum is shown below. Figure 2 As shown, HRMS (m / z): 993.2355 [M+H] + .

[0018] Example 2 Preparation of Adhesive S1: Add 300 ml of dichloromethane, 0.1 mol of 4,4'-diaminodiphenylmethane and 0.204 mol of cyanuric chloride to a reaction vessel, stir and mix well, add 0.11 mol of potassium carbonate, react at 0℃ for 5 h, filter, distill under reduced pressure at 30℃ for 1 h, add 200 ml of diethyl ether and stir to precipitate, filter, dry under vacuum at 40℃ for 5 h to obtain intermediate 1; S2: Add 300 ml DMF and 0.1 mol intermediate 1 to the reaction vessel, stir and mix well, add 200 ml of aqueous solution containing 0.205 mol LO-phosphoserine, adjust the pH to 11 with 10 wt% NaOH solution, heat to 45℃, react for 6 h, cool to room temperature, add 200 ml deionized water to dilute, adjust the pH to 4 with 1 M HCl solution, precipitate, filter, wash with deionized water (2 × 80 ml), and vacuum dry at 60℃ for 12 h to obtain intermediate 2; S3: Add 800 ml DMF, 0.1 mol intermediate 2 and 0.206 mol 2-aminophenylboronic acid to the reaction vessel, stir and mix well, adjust the pH to 11 with 10 wt% NaOH solution, heat to 85℃, react for 17 h, cool to room temperature, add 1000 ml diethyl ether and stir to precipitate, filter, wash successively with a mixed solution of 100 ml diethyl ether and anhydrous ethanol (volume ratio of diethyl ether and anhydrous ethanol is 1:1) and deionized water (2 × 80 ml), and vacuum dry at 60℃ for 12 h to obtain the binder.

[0019] Example 3 Preparation of Adhesive S1: Add 300 ml of dichloromethane, 0.1 mol of 4,4'-diaminodiphenylmethane and 0.205 mol of cyanuric chloride to a reaction vessel, stir and mix well, add 0.11 mol of potassium carbonate, react at 0℃ for 6 h, filter, distill under reduced pressure at 30℃ for 1 h, add 200 ml of diethyl ether and stir to precipitate, filter, dry under vacuum at 40℃ for 5 h to obtain intermediate 1; S2: Add 300 ml DMF and 0.1 mol intermediate 1 to the reaction vessel, stir and mix well, add 200 ml of aqueous solution containing 0.206 mol LO-phosphoserine, adjust the pH to 11 with 10 wt% NaOH solution, heat to 50℃, react for 5 h, cool to room temperature, add 200 ml deionized water to dilute, adjust the pH to 4 with 1 M HCl solution, precipitate, filter, wash with deionized water (2 × 80 ml), and vacuum dry at 60℃ for 12 h to obtain intermediate 2; S3: Add 800 ml DMF, 0.1 mol intermediate 2 and 0.208 mol 2-aminophenylboronic acid to the reaction vessel, stir and mix well, adjust the pH to 11 with 10 wt% NaOH solution, heat to 90℃, react for 15 h, cool to room temperature, add 1000 ml diethyl ether and stir to precipitate, filter, wash successively with a mixed solution of 100 ml diethyl ether and anhydrous ethanol (volume ratio of diethyl ether and anhydrous ethanol is 1:1) and deionized water (2 × 80 ml), and vacuum dry at 60℃ for 12 h to obtain the binder.

[0020] Example 4: Preparation of textured coating for sliding bearings (1) The bearing steel (100mm×50mm×10mm) was immersed in acetone and ultrasonically cleaned (50Hz, 30min), vacuum dried at 80℃ for 10min, and pretreated with YAG laser. Under argon protection, the scanning speed was set to 80mm / s, the repetition frequency to 25KHz, the spot diameter to 30μm, the pulse width to 5ns, and the groove spacing to 100μm to obtain the textured matrix. (2) Mix 70g of anhydrous ethanol, 1g of binder (prepared in Example 1), 15g of titanium nitride and 15g of titanium powder, put them into a ball mill, use grinding balls with a diameter of 5mm and 3mm, the weight ratio of 5mm grinding balls to 3mm grinding balls is 1:1, the ball-to-material ratio is 10:1, grind at 300r / min for 15min, stop for 5min, repeat 20 times, take out the grinding balls, and obtain a suspension; (3) The suspension was sprayed onto the textured substrate using a plasma spray gun. The arc power was set to 70kW, the argon flow rate to 50L / min, the hydrogen flow rate to 10L / min, the feeding speed to 25ml / min, the spraying power to 90kW, the spraying distance to 80mm, the moving speed to 200mm / s, and the spraying thickness to 200μm, to obtain the textured coating on the sliding bearing.

[0021] Example 5: Preparation of textured coating for sliding bearings (1) The bearing steel (100mm×50mm×10mm) was immersed in acetone and ultrasonically cleaned (50Hz, 30min), vacuum dried at 80℃ for 10min, and pretreated with YAG laser. Under argon protection, the scanning speed was set to 90mm / s, the repetition frequency to 28KHz, the spot diameter to 30μm, the pulse width to 8ns, and the groove spacing to 120μm to obtain the textured matrix. (2) Mix 70g of anhydrous ethanol, 1.2g of binder (prepared in Example 2), 18g of titanium nitride and 12g of titanium powder, put them into a ball mill, use grinding balls with a diameter of 5mm and 3mm, the weight ratio of 5mm grinding balls to 3mm grinding balls is 1:1, the ball-to-material ratio is 10:1, grind at 300r / min for 15min, stop for 5min, repeat 20 times, take out the grinding balls, and obtain a suspension; (3) The suspension was sprayed onto the textured substrate using a plasma spray gun. The arc power was set to 80kW, the argon flow rate to 50L / min, the hydrogen flow rate to 10L / min, the feeding speed to 25ml / min, the spraying power to 90kW, the spraying distance to 80mm, the moving speed to 250mm / s, and the spraying thickness to 250μm, to obtain the textured coating on the sliding bearing.

[0022] Example 6: Preparation of Textured Coating for Sliding Bearings (1) The bearing steel (100mm×50mm×10mm) was immersed in acetone and ultrasonically cleaned (50Hz, 30min), vacuum dried at 80℃ for 10min, and pretreated with YAG laser. Under argon protection, the scanning speed was set to 100mm / s, the repetition frequency to 30KHz, the spot diameter to 30μm, the pulse width to 10ns, and the groove spacing to 150μm to obtain the textured matrix. (2) Mix 70g of anhydrous ethanol, 1.5g of binder (prepared in Example 1), 20g of titanium nitride and 10g of titanium powder, put them into a ball mill, use grinding balls with a diameter of 5mm and 3mm, the weight ratio of 5mm grinding balls to 3mm grinding balls is 1:1, the ball-to-material ratio is 10:1, grind at 300r / min for 15min, stop for 5min, repeat 20 times, take out the grinding balls, and obtain a suspension; (3) The suspension was sprayed onto the textured substrate using a plasma spray gun. The arc power was set to 90kW, the argon flow rate to 50L / min, the hydrogen flow rate to 10L / min, the feeding speed to 25ml / min, the spraying power to 90kW, the spraying distance to 80mm, the moving speed to 300mm / s, and the spraying thickness to 300μm, to obtain the textured coating on the sliding bearing.

[0023] Comparative Example 1 The preparation method of the textured coating for sliding bearings is basically the same as in Example 5, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 4,4'-diaminodiphenylmethane in step S1 is replaced with 0.2 mol of aniline, LO-phosphoserine in step S2 is replaced with 0.102 mol, and 2-aminophenylboronic acid in step S3 is replaced with 0.103 mol.

[0024] Comparative Example 2 The preparation method of the textured coating for sliding bearings is basically the same as in Example 5, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that the 4,4'-diaminodiphenylmethane in step S1 is replaced with an equimolar amount of 4,4'-diaminodicyclohexylmethane.

[0025] Comparative Example 3 The preparation method of the textured coating for sliding bearings is basically the same as that in Example 6, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 4,4'-diaminodiphenylmethane in step S1 is replaced with an equimolar amount of p-phenylenediamine.

[0026] Comparative Example 4 The preparation method of the textured coating for sliding bearings is basically the same as that in Example 6, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that the 4,4'-diaminodiphenylmethane in step S1 is replaced with an equimolar amount of 4,4'-diaminodiphenyl ether.

[0027] Comparative Example 5 The preparation method of the textured coating for sliding bearings is basically the same as in Example 5, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that LO-phosphoserine in step S2 is replaced with an equimolar amount of DL-serine.

[0028] Comparative Example 6 The preparation method of the textured coating for sliding bearings is basically the same as in Example 5, except that the adhesive is replaced with an equal weight of adhesive prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 2-aminophenylboronic acid in step S3 is replaced with an equimolar amount of 4-aminophenylboronic acid.

[0029] The bearing steel used in the embodiments and comparative examples of this application is GCr18Mo; the titanium nitride is of type LT-N-002-3 with an average particle size of 1μm, and is produced by Shanghai Liantian Materials Technology Co., Ltd.; the titanium powder has a particle size distribution of 15-75μm and is produced by Suzhou Keyue Materials Technology Co., Ltd.

[0030] The hardness and wear resistance of the textured coatings used in the sliding bearings prepared in Examples 4-6 and Comparative Examples 1-6 were tested, and the test results are shown in Table 1.

[0031] Hardness Testing: The hardness of this layer was tested using a Vickers hardness tester with a load of 1 kg and a loading time of 10 s. The length of the diagonal of the indentation was then measured using a reading microscope, and the Vickers hardness H was calculated using the following formula:

[0032] Where R is the applied load; d is the average value of the two diagonals of the indentation.

[0033] Wear resistance testing: An MS-T3000 ball-and-disc friction and wear tester was used to conduct wear tests on the samples under dry sliding conditions. The test employed a reciprocating linear motion with ball-to-surface contact. The friction pair consisted of 3mm diameter cemented carbide balls. The test load was 4N, the average friction speed was 100r / m, and the test wear time was 60min. The volume of the wear track profile was measured using an optical profilometer, and the wear rate was calculated using the volumetric method, as shown in the following formula: Where L is the sliding distance; V is the wear volume; This is the normal load.

[0034] Table 1 Performance Test Data As can be seen from the data in Examples 4-6 in Table 1, the textured coating for sliding bearings prepared by the present invention has excellent hardness and friction resistance.

[0035] The binder added to the textured coating for sliding bearings prepared in this invention uses diphenylmethane as its core and incorporates triazine rings, phosphoric acid, boric acid, and carboxylic acid structures. Specifically, the diphenylmethane and triazine rings in the binder act as rigid aromatic structures, enhancing the rigidity of the molecular skeleton and preventing structural disintegration during ball milling, ensuring that other functional groups (such as carboxyl groups, phosphoric acid, and boric acid) can function effectively. The carboxyl groups can form hydrogen bonds with titanium nitride and titanium powder, improving the binder's wetting ability on the powder surface and promoting uniform spreading of the binder on the particle surface. The triazine rings coordinate with titanium and titanium nitride, improving the binder's anchoring ability on the particle surface and synergistically inhibiting powder agglomeration with the carboxyl groups, thus improving the dispersion stability of the mixture. Phosphoric acid and boric acid can form PO-Ti and BO-Ti covalent bonds with the surfaces of titanium nitride and titanium powder, acting as molecular bridges between the particles and the binder. Furthermore, during high-temperature spraying, a low-temperature glass phase is formed, enabling wetting and penetration of the metal surface at high temperatures, improving the density and hardness of the coating.

[0036] In Comparative Example 2, 4,4′-diaminodicyclohexylmethane was used instead of 4,4′-diaminodiphenylmethane, resulting in a lack of the high rigidity and thermal stability inherent in aromatic systems in the binder molecules. This led to insufficient structural stability during ball milling, and the cyclohexyl ring structure exhibited weaker interaction with the surfaces of metal and ceramic particles, making it difficult to form a stable chemical anchoring interface, thus reducing coating performance. In Comparative Example 3, p-phenylenediamine was used instead of diphenylmethane, resulting in a highly linear, rigid aromatic structure in the binder molecules. However, this resulted in insufficient molecular flexibility and configurational adjustment capabilities, making it difficult to adapt to complex particle surface morphologies during ball milling and spraying. This resulted in poor interfacial spreading and stress buffering capabilities, easily leading to stress concentration at the coating interface. In Comparative Example 4, the diphenyl ether structure in the binder allowed for greater rotational freedom between benzene rings, reducing molecular rigidity and making the binder prone to structural disintegration or conformational changes, leading to performance degradation. In Example 5, the boric acid in the binder can form a coordinate bond with the adjacent N, enhancing the stability of the bridging structure. In contrast, in Comparative Example 5, the boric acid and N exist in the para position, resulting in reduced structural stability and decreased coating performance.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a textured coating for sliding bearings, characterized in that, Includes the following steps: (1) The bearing steel is pretreated by laser to obtain a textured matrix; (2) The solvent, binder, titanium nitride and titanium powder are mixed and ball-milled to obtain a suspension; (3) The suspension is sprayed onto the textured substrate using plasma spraying to obtain a coating; The adhesive is prepared by the following method: S1: 4,4'-Diaminodiphenylmethane reacts with cyanuric chloride to produce intermediate 1. S2: Intermediate 1 reacts with LO-phosphoserine to generate intermediate 2. S3: Intermediate 2 reacts with 2-aminophenylboronic acid to form a binder.

2. The method for preparing a textured coating for sliding bearings according to claim 1, characterized in that, In step S1, the molar ratio of 4,4'-diaminodiphenylmethane to cyanuric chloride is 1:(2.03-2.05).

3. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step S2, the molar ratio of intermediate 1 to LO-phosphoserine is 1:(2.04-2.06).

4. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step S3, the molar ratio of intermediate 2 to 2-aminophenylboronic acid is 1:(2.05-2.08).

5. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step (1), the scanning speed of the laser preprocessing is 80-100 mm / s and the repetition frequency is 25-30 kHz.

6. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step (1), the pulse width of the laser preprocessing is 5-10 ns.

7. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step (2), the ratio of solvent, binder, titanium nitride and titanium powder is 7:(0.1-0.15):(1.5-2):(1-1.5).

8. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step (3), the arc power of the plasma spraying is 70-90kW.

9. The method for preparing a textured coating for a sliding bearing according to claim 1, characterized in that, In step (3), the plasma spray gun moves at a speed of 200-300 mm / s.

10. A textured coating for sliding bearings, characterized in that, It is obtained by the preparation method according to any one of claims 1-9.

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