Superhard wear-resistant protective coating, preparation method thereof and application of superhard wear-resistant protective coating in aero-engine blade

Abstract

The invention discloses a superhard wear-resistant protective coating, a preparation method thereof and application of the superhard wear-resistant protective coating in aero-engine blades, and relates to the technical field of coating preparation. The preparation method of the superhard wear-resistant protective coating comprises the following steps that the surface of a TC4 titanium alloy matrix is pretreated, and the treated matrix is obtained; uniformly mixing titanium powder and graphene powder, and then adding a binder to obtain mixed slurry; uniformly coating the surface of the treated matrix with the mixed slurry, and drying to form a preset powder layer; argon arc welding equipment is adopted, scanning cladding is conducted on the preset powder layer under argon protection, cooling is conducted to the room temperature, and the protective coating which is cladded on the TC4 titanium alloy matrix is obtained; the superhard wear-resistant protective coating prepared by the invention has good bonding strength, hardness and protective performance, and can be applied to aero-engine blades.

Description

Technical Field

[0001] This invention relates to the field of coating preparation technology, specifically to an ultra-hard wear-resistant protective coating, its preparation method, and its application in aero-engine blades. Background Technology

[0002] Aero-engine blades operate under harsh environments characterized by high temperature, high speed, high load, and particulate erosion. Their surface protection performance directly impacts engine efficiency, safety, and service life. Coating hardness is a key factor determining blade wear resistance, erosion resistance, and resistance to fretting wear. Current aero-engine blade surfaces often employ metal protective coatings or ceramic-based thermal barrier coatings. While these improve high-temperature resistance and oxidation resistance to some extent, they still fall short in achieving a balance between high hardness and high toughness. On one hand, some metal-based protective coatings have relatively low hardness, making them prone to plastic deformation and wear under the scouring action of high-speed airflow carrying sand, dust, and other solid particles, leading to coating failure. On the other hand, while traditional high-hardness ceramic coatings possess high microhardness, their brittle structure makes them susceptible to microcracks that propagate under blade start-stop cycles, thermal shock, and vibration loads, resulting in spalling and failure. Furthermore, existing coatings still need improvement in terms of hardness distribution uniformity and interfacial bonding strength, making it difficult to simultaneously meet the comprehensive requirements of ultra-high hardness, excellent wear resistance, and long-term service stability. Therefore, developing a protective coating that combines ultra-high hardness, excellent wear resistance, and good bonding strength, and stably applying it to the surface of aero-engine blades, is of great significance for improving the service life of blades and the overall performance of the engine. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide an ultra-hard wear-resistant protective coating, its preparation method, and its application in aero-engine blades.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an ultra-hard wear-resistant protective coating includes the following steps: (1) The surface of the TC4 titanium alloy substrate is pretreated to obtain the treated substrate; (2) Mix titanium powder and graphene powder evenly, then add binder to obtain a mixed slurry; coat the mixed slurry evenly on the treated substrate surface, and dry to form a pre-placed powder layer; (3) Under argon protection, the pre-placed powder layer is scanned and clad, and then cooled to room temperature to obtain a protective coating clad on the TC4 titanium alloy substrate; The adhesive is prepared by the following method: S1: Methyl linoleate reacts with sodium hydride to form intermediate 1. S2: Intermediate 1 reacts with 4-(chloromethyl)benzyl alcohol to generate intermediate 2. S3: Intermediate 2 reacts with 6-aminohexanephosphoric acid to generate intermediate 3. S4: Intermediate 3 reacts with 3-mercaptopropyltrimethoxysilane to form a binder.

[0005] In step S2, the molar ratio of intermediate 1 to 4-(chloromethyl)benzyl alcohol is (1.05-1.1):1.

[0006] In step S3, the molar ratio of intermediate 2 to 6-aminohexanephosphoric acid is (2.02-2.08):1.

[0007] In step S4, the molar ratio of intermediate 3 to 3-mercaptopropyltrimethoxysilane is 1:(8.05-8.1).

[0008] In step (2), the mass ratio of titanium powder, graphene, and binder is 10:(1-2):(0.5-1).

[0009] In step (3), the cladding speed is 50-200 mm / min.

[0010] In step (3), the current intensity during cladding is 80-150A.

[0011] In step (3), the voltage during cladding is 14-18V.

[0012] An ultra-hard wear-resistant protective coating is prepared by the above method.

[0013] Application of an ultra-hard wear-resistant protective coating in aero-engine blades.

[0014] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include: The superhard wear-resistant protective coating prepared by this invention has excellent bonding strength, hardness and protective performance. Attached Figure Description

[0015] Figure 1 The 1H NMR spectrum of the binder prepared in step S4 of Example 1; Figure 2 This is a high-resolution mass spectrum of the adhesive prepared in step S4 of Example 1. Detailed Implementation

[0016] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0017] Example 1: Preparation of Adhesive S1: Under nitrogen protection and in an ice bath, 150 ml of anhydrous tetrahydrofuran was added to the reactor and stirred. Then, 0.13 mol of sodium hydride was added in five batches (10 min apart). 150 ml of DMF solution containing 0.1 mol of methyl linoleate was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 50 °C and reacted for 8 h. The mixture was then cooled to 0 °C, and 150 ml of saturated ammonium chloride aqueous solution was slowly added to quench the reaction. The mixture was diluted with 200 ml of deionized water and extracted three times with ethyl acetate (150 ml each time). The organic phases were combined, washed with 50 ml of saturated brine, dried with 30 g of anhydrous sodium sulfate, filtered, and rotary evaporated at 45 °C for 1 h. The mixture was then vacuum dried at 50 °C for 12 h to obtain intermediate 1. The reaction equation is shown below: Its 1H NMR spectrum data is as follows: 1 H NMR (400 MHz, Chloroform- d ) δ 5.59 – 5.32 (m, 8H), 3.69 (s, 3H), 3.56 (t, J = 7.3 Hz, 1H), 2.57 – 2.33 (m, 6H), 2.10 – 1.98(m, 8H), 1.93 – 1.22 (m, 32H), 0.96 – 0.83 (m, 6H), HRMS (m / z): 557.4858[M+H] + .

[0018] S2: Under nitrogen protection, 400 mL of xylene, 0.105 mol of intermediate 1, 0.1 mol of 4-(chloromethyl)benzyl alcohol, and 0.005 mol of dibutyltin oxide were added to the reactor. The mixture was stirred and stirred until homogeneous, then refluxed for 6 h (methanol was removed using a water separator during the reaction). After cooling to room temperature, the mixture was washed three times with saturated brine (100 mL each time), dried with 40 g of anhydrous magnesium sulfate, filtered, and the filtrate was distilled under reduced pressure at 70 °C for 2 h and dried under vacuum at 60 °C for 12 h to obtain intermediate 2. The reaction equation is shown below: Its 1H NMR data are as follows: 1 H NMR (400 MHz, DMSO- d 6) δ 7.38 – 7.19 (m, 4H), 5.55 – 5.35 (m, 8H), 5.24 – 5.13 (m, 2H), 4.64 (t, J = 0.8 Hz, 2H), 3.60 (t,J = 7.7 Hz, 1H), 2.58 – 2.32 (m, 6H), 2.08 – 1.96 (m, 8H), 1.93 – 1.18 (m,32H), 0.95 – 0.81 (m, 6H); HRMS (m / z): 681.4938[M+H] + .

[0019] S3: Under nitrogen protection, 800 ml of anhydrous DMF (N,N-dimethylformamide), 0.202 mol of intermediate 2, 0.1 mol of 6-aminohexanephosphoric acid, and 20 g of 4A molecular sieve were stirred and mixed. 0.012 mol of tetraethylammonium bromide and 0.12 mol of K₂CO₃ were added, and the mixture was heated to 60 °C and reacted for 8 h. After cooling to room temperature, the mixture was filtered, and the solution was rotary evaporated at 70 °C for 2 h to obtain a concentrated solution. 400 ml of cold anhydrous diethyl ether was slowly added to the concentrated solution under ice bath conditions, and the precipitate was stirred to precipitate. The precipitate was filtered, and the filter cake was washed with cold anhydrous diethyl ether (3 × 100 ml). The solution was then vacuum dried at 60 °C for 8 h to obtain intermediate 3. The reaction equation is shown below: Its 1H NMR data are as follows: 1 H NMR (400 MHz, DMSO- d 6 ) δ 8.74 (s, 2H), 7.26 (s,8H), 5.54 – 5.36 (m, 16H), 5.25 – 5.15 (m, 4H), 3.72 – 3.66 (m, 4H), 3.60 (t,J = 7.7 Hz, 2H), 2.64 – 2.30 (m, 14H), 2.08 – 1.78 (m, 20H), 1.67 – 1.19 (m,70H), 0.96 – 0.81 (m, 12H); HRMS (m / z): 1472.1241[M+H] + .

[0020] S4: Under nitrogen protection, add 1000 ml tetrahydrofuran, 0.1 mol intermediate 3, 0.805 mol 3-mercaptopropyltrimethoxysilane, and 1.5 g photoinitiator 184 to the reactor, stir and mix thoroughly, and incubate at room temperature with an intensity of 8.4 mW / cm². 2After irradiation under a 365nm UV LED lamp for 12 hours, the mixture was rotary evaporated at 40℃ for 1 hour. The precipitate was then slowly added to 800mL of cold diethyl ether, stirred, filtered, washed three times with 100mL of cold diethyl ether each time, and vacuum dried at 40℃ for 12 hours to obtain the binder. The reaction equation is shown below: Its hydrogen NMR spectrum is as follows Figure 1 As shown, its 1H NMR spectrum data are as follows: 1 H NMR (400 MHz, Chloroform- d δ 7.95 (s, 2H), 7.26 (s, 8H), 5.30 – 5.07 (m, 4H), 3.69 (d, J = 0.6 Hz, 4H), 3.59 (s, 72H), 3.57 (d, J = 7.7 Hz, 2H), 2.90 (p, J = 5.5 Hz, 8H), 2.66– 2.31 (m, 22H), 2.02 – 1.18 (m, 130H), 0.95 – 0.72 (m, 28H); its high-resolution mass spectrum is shown below. Figure 2 As shown, HRMS (m / z): 3040.5956 [M+H] + .

[0021] Example 2: Preparation of adhesive: S1: Under nitrogen protection and in an ice bath, 150 ml of anhydrous tetrahydrofuran was added to the reactor and stirred. Then, 0.13 mol of sodium hydride was added in batches (5 batches, 10 min apart). 150 ml of DMF solution containing 0.1 mol of methyl linoleate was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 55 °C and reacted for 7.5 h. The mixture was then cooled to 0 °C and quenched by slowly adding 150 ml of saturated ammonium chloride aqueous solution. 200 ml of deionized water was added for dilution, and the mixture was extracted three times with ethyl acetate (150 ml each time). The organic phases were combined, washed with 50 ml of saturated brine, dried with 30 g of anhydrous sodium sulfate, filtered, rotary evaporated at 45 °C for 1 h, and vacuum dried at 50 °C for 12 h to obtain intermediate 1. S2: Under nitrogen protection, 400 mL of xylene, 0.108 mol of intermediate 1, 0.1 mol of 4-(chloromethyl)benzyl alcohol, and 0.005 mol of dibutyltin oxide were added to the reactor. The mixture was stirred and stirred until homogeneous. The mixture was then refluxed for 5 h (methanol was removed using a water separator during the reaction). After cooling to room temperature, the mixture was washed three times with saturated brine (100 mL each time), dried with 40 g of anhydrous magnesium sulfate, filtered, and the filtrate was distilled under reduced pressure at 70 °C for 2 h and dried under vacuum at 60 °C for 12 h to obtain intermediate 2. S3: Under nitrogen protection, 800 ml of anhydrous DMF, 0.205 mol of intermediate 2, 0.1 mol of 6-aminohexane phosphoric acid, and 20 g of 4A molecular sieve were stirred and mixed. 0.012 mol of tetraethylammonium bromide and 0.12 mol of K2CO3 were added, and the mixture was heated to 65 °C and reacted for 7 h. After cooling to room temperature, the mixture was filtered and evaporated at 70 °C for 2 h to obtain a concentrated solution. 400 ml of cold anhydrous diethyl ether was slowly added to the concentrated solution under ice bath conditions and stirred to precipitate the precipitate. The precipitate was filtered, and the filter cake was washed with cold anhydrous diethyl ether (3 × 100 ml). The mixture was then dried under vacuum at 60 °C for 8 h to obtain intermediate 3. S4: Under nitrogen protection, add 1000 ml tetrahydrofuran, 0.1 mol intermediate 3, 0.808 mol 3-mercaptopropyltrimethoxysilane, and 1.5 g photoinitiator 184 to the reactor, stir and mix thoroughly, and incubate at room temperature with an intensity of 8.4 mW / cm². 2 After 14 hours of irradiation under a 365nm UV LED lamp, the mixture was rotary evaporated at 40℃ for 1 hour, then slowly added to 800mL of cold ether. The mixture was stirred, and a precipitate was formed. The precipitate was filtered, washed three times with 100mL of cold ether each time, and then vacuum dried at 40℃ for 12 hours to obtain the binder.

[0022] Example 3: Preparation of adhesive: S1: Under nitrogen protection and in an ice bath, 150 ml of anhydrous tetrahydrofuran was added to the reactor and stirred. Then, 0.13 mol of sodium hydride was added in batches (5 batches, 10 min apart). 150 ml of DMF solution containing 0.1 mol of methyl linoleate was slowly added dropwise over 30 min. After the addition was complete, the temperature was raised to 60 °C and reacted for 7 h. The mixture was then cooled to 0 °C and quenched by slowly adding 150 ml of saturated ammonium chloride aqueous solution. 200 ml of deionized water was added for dilution. The mixture was then extracted three times with ethyl acetate (150 ml each time). The organic phases were combined, washed with 50 ml of saturated brine, dried with 30 g of anhydrous sodium sulfate, filtered, and rotary evaporated at 45 °C for 1 h. The mixture was then vacuum dried at 50 °C for 12 h to obtain intermediate 1. S2: Under nitrogen protection, 400 mL of xylene, 0.11 mol of intermediate 1, 0.1 mol of 4-(chloromethyl)benzyl alcohol, and 0.005 mol of dibutyltin oxide were added to the reactor. The mixture was stirred and stirred until homogeneous. The mixture was then refluxed for 4 h (methanol was removed using a water separator during the reaction). After cooling to room temperature, the mixture was washed three times with saturated brine (100 mL each time), dried with 40 g of anhydrous magnesium sulfate, filtered, and the filtrate was distilled under reduced pressure at 60 °C for 1.5 h and then dried under vacuum at 60 °C for 12 h to obtain intermediate 2. S3: Under nitrogen protection, 800 ml of anhydrous DMF, 0.208 mol of intermediate 2, 0.1 mol of 6-aminohexane phosphoric acid, and 20 g of 4A molecular sieve were stirred and mixed. 0.012 mol of tetraethylammonium bromide and 0.12 mol of K2CO3 were added, and the mixture was heated to 70 °C and reacted for 6 h. After cooling to room temperature, the mixture was filtered and evaporated at 70 °C for 2 h to obtain a concentrated solution. 400 ml of cold anhydrous diethyl ether was slowly added to the concentrated solution under ice bath conditions and stirred to precipitate the precipitate. The precipitate was filtered, and the filter cake was washed with cold anhydrous diethyl ether (3 × 100 ml). The mixture was then dried under vacuum at 60 °C for 8 h to obtain intermediate 3. S4: Under nitrogen protection, add 1000 ml tetrahydrofuran, 0.1 mol intermediate 3, 0.81 mol 3-mercaptopropyltrimethoxysilane, and 1.5 g photoinitiator 184 to the reactor, stir and mix thoroughly, and incubate at room temperature with an intensity of 8.4 mW / cm². 2 After 16 hours of irradiation under a 365nm UV LED lamp, the mixture was rotary evaporated at 40℃ for 1 hour. The precipitate was then slowly added to 800mL of cold ether and stirred. The precipitate was filtered, washed three times with 100mL of cold ether each time, and then vacuum dried at 40℃ for 12 hours to obtain the binder.

[0023] Example 4: Preparation of protective coating: (1) Take a TC4 titanium alloy substrate (100mm×50mm×10mm), use 400-grit sandpaper to mechanically grind the surface of the substrate until there are no obvious scratches on the surface; then place it in acetone for ultrasonic cleaning for 15min (300W, 40kHz), then in anhydrous ethanol for ultrasonic cleaning for 10min, and blow dry with hot air at 60℃ to obtain the treated substrate; (2) Weigh 100g of titanium powder and 10g of graphene powder and place them in 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 2:1 and the ball-to-material ratio is 15:1. Grind at 500r / min for 15min, stop for 15min, and repeat 10 times to mix evenly. Then add 50ml of aqueous solution containing 5g of binder (prepared in Example 1) and stir at 500r / min for 20min to mix evenly to obtain a mixed slurry. Use a scraper to evenly coat the slurry onto the treated substrate surface and place it in a 60℃ constant temperature drying oven to dry for 2h to obtain a pre-placed powder layer (thickness of 0.2mm). (3) Place the pre-placed powder layer on the workbench of the argon arc cladding equipment and perform cladding treatment under pure argon protection. The argon flow rate is controlled at 15L / min; the cladding current is 80A, the voltage is 14V, the cladding speed is 50mm / min, and the arc length is 2mm. After cladding, allow it to cool naturally to room temperature to obtain a protective coating clad on the TC4 titanium alloy substrate.

[0024] Example 5: Preparation of protective coating: (1) Take a TC4 titanium alloy substrate (100mm×50mm×10mm), use 400-grit sandpaper to mechanically grind the surface of the substrate until there are no obvious scratches on the surface; then place it in acetone for ultrasonic cleaning for 15min (300W, 40kHz), then in anhydrous ethanol for ultrasonic cleaning for 10min, and blow dry with hot air at 60℃ to obtain the treated substrate; (2) Weigh 100g of titanium powder and 15g of graphene powder and place them in 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 2:1 and the ball-to-material ratio is 15:1. Grind at 500r / min for 15min, stop for 15min, and repeat 10 times to mix evenly. Then add 50ml of aqueous solution containing 8g of binder (prepared in Example 2), stir at 500r / min for 20min to mix evenly, and obtain a mixed slurry. Use a scraper to evenly coat the slurry onto the treated substrate surface, and place it in a 60℃ constant temperature drying oven to dry for 2h to obtain a pre-placed powder layer (thickness of 0.2mm). (3) Place the pre-placed powder layer on the worktable of the argon arc cladding equipment and perform cladding treatment under pure argon protection, wherein the argon flow rate is controlled at 15L / min; the cladding current is 120A, the voltage is 16V, the cladding speed is 100mm / min, and the arc length is 2.5mm; after the cladding is completed, it is naturally cooled to room temperature to obtain a protective coating clad on the TC4 titanium alloy substrate.

[0025] Example 6: Preparation of protective coating: (1) Take a TC4 titanium alloy substrate (100mm×50mm×10mm), use 400-grit sandpaper to mechanically grind the surface of the substrate until there are no obvious scratches on the surface; then place it in acetone for ultrasonic cleaning for 15min (300W, 40kHz), then in anhydrous ethanol for ultrasonic cleaning for 10min, and blow dry with hot air at 60℃ to obtain the treated substrate; (2) Weigh 100g of titanium powder and 20g of graphene powder and place them in 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 2:1 and the ball-to-material ratio is 15:1. Grind at 500r / min for 15min, stop for 15min, and repeat 10 times to mix evenly. Then add 50ml of aqueous solution containing 10g of binder (prepared in Example 3) and stir at 500r / min for 20min to mix evenly to obtain a mixed slurry. Use a scraper to evenly coat the slurry onto the treated substrate surface and place it in a 60℃ constant temperature drying oven to dry for 2h to obtain a pre-placed powder layer (thickness of 0.2mm). (3) Place the pre-placed powder layer on the workbench of the argon arc cladding equipment and perform cladding treatment under pure argon protection. The argon flow rate is controlled at 15L / min; the cladding current is 150A, the voltage is 18V, the cladding speed is 200mm / min, and the arc length is 3mm. After cladding, allow it to cool naturally to room temperature to obtain a protective coating clad on the TC4 titanium alloy substrate.

[0026] Comparative Example 1 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that methyl linoleate in step S1 is replaced with an equimolar amount of methyl oleate; and the feed ratio of 3-mercaptopropyltrimethoxysilane in step S4 is replaced with 0.404 mol.

[0027] Comparative Example 2 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 4-(chloromethyl)benzyl alcohol in step S2 is replaced with an equimolar amount of 5-chloro-1-pentanol.

[0028] Comparative Example 3 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 6-aminohexane phosphate in step S3 is replaced with an equimolar amount of (2-aminoethyl)phosphonate diethyl ester.

[0029] Comparative Example 4 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 6-aminohexanephosphoric acid in step S3 is replaced with an equimolar amount of aminomethylphosphonic acid.

[0030] Comparative Example 5 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that 3-mercaptopropyltrimethoxysilane in step S4 is replaced with an equimolar amount of mercaptopropylmethyldimethoxysilane.

[0031] Comparative Example 6 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: The preparation method of the adhesive is basically the same as that in Example 2, except that the amount of 3-mercaptopropyltrimethoxysilane fed in step S4 is 0.608 mol.

[0032] Comparative Example 7 The preparation method of the superhard wear-resistant protective coating is basically the same as that in Example 5, except that the binder in step (2) is replaced with an equal weight of binder prepared by the following method: S1: Under nitrogen protection, 400 mL of xylene, 0.108 mol of methyl linoleate, 0.1 mol of 4-(chloromethyl)benzyl alcohol, and 0.005 mol of dibutyltin oxide were added to the reactor. The mixture was stirred and stirred until homogeneous. The mixture was then refluxed for 5 h (methanol was removed using a water separator during the reaction). After cooling to room temperature, the mixture was washed three times with saturated brine (100 mL each time), dried with 40 g of anhydrous magnesium sulfate, filtered, and the filtrate was distilled under reduced pressure at 70 °C for 2 h and dried under vacuum at 60 °C for 12 h to obtain intermediate A. S2: Under nitrogen protection, 800 ml of anhydrous DMF, 0.205 mol of intermediate A, 0.1 mol of 6-aminohexane phosphoric acid, and 20 g of 4A molecular sieve were stirred and mixed. 0.012 mol of tetraethylammonium bromide and 0.12 mol of K2CO3 were added, and the mixture was heated to 65 °C and reacted for 7 h. After cooling to room temperature, the mixture was filtered and evaporated at 70 °C for 2 h to obtain a concentrated solution. 400 ml of cold anhydrous diethyl ether was slowly added to the concentrated solution under ice bath conditions, and the precipitate was stirred to precipitate. The precipitate was filtered, and the filter cake was washed with cold anhydrous diethyl ether (3 × 100 ml). The mixture was then dried under vacuum at 60 °C for 8 h to obtain intermediate B. S3: Under nitrogen protection, add 1000 ml tetrahydrofuran, 0.1 mol intermediate B, 0.408 mol 3-mercaptopropyltrimethoxysilane, and 1.5 g photoinitiator 184 to the reactor, stir and mix thoroughly, and at room temperature, at an intensity of 8.4 mW / cm². 2 After 14 hours of irradiation under a 365nm UV LED lamp, the mixture was rotary evaporated at 40℃ for 1 hour, then slowly added to 800mL of cold ether. The mixture was stirred, and a precipitate was formed. The precipitate was filtered, washed three times with 100mL of cold ether each time, and then vacuum dried at 40℃ for 12 hours to obtain the binder.

[0033] The TC4 titanium alloy used in the embodiments and comparative examples of this application is an aerospace-grade TC4 titanium alloy plate, grade TA1, produced by Baoji Likun Titanium Industry Co., Ltd.; the titanium powder is model CW-TiC-001, with an average particle size of 50nm, produced by Shanghai Chaowei Nanotechnology Co., Ltd.; the graphene powder is model HQNANO-GR-002, produced by Suzhou CarbonFeng Graphene Technology Co., Ltd.

[0034] The protective coatings prepared in Examples 4-6 and Comparative Examples 1-7 were tested for bonding strength, hardness, and protective performance.

[0035] Bond strength test: The protective coating was cut into 25mm diameter circular specimens. Both sides of each specimen were bonded to a mating rod (Φ25mm×30mm) using FM-1000 high-temperature film. The specimens were then held at 190℃ for 2 hours in a muffle furnace. The bonded specimens were then subjected to a tensile test on a LE5105 electronic universal testing machine at a loading rate of 2mm / min. The bond strength δ was calculated using the following formula.

[0036] Where F is the maximum load when the coating breaks, and S is the coating area.

[0037] Hardness Testing: A square pyramidal diamond with an angle of 136° between its opposing faces was indented into the superhard wear-resistant protective coating using a Vickers hardness tester. The applied load was 1 kgf, and the holding time was 10 s. The length of the diagonal of the indentation was then measured using a reading microscope. The Vickers hardness H was calculated using the following formula: Where P is the applied load; d is the average value of the two diagonals of the indentation.

[0038] Protective performance test: The protective coatings prepared in Examples 4-6 and Comparative Examples 1-7 were subjected to air-cooling cycle treatment (the protective coating was placed in an electric furnace at 1100℃ and kept at 0.5h, then taken out and quickly transferred to room temperature (25±5℃) to cool to room temperature, which is one cycle) until the peeling area of ​​the coating reached 20% of the total area of ​​the coating. At this point, the protective coating was considered to have failed, and the corresponding number of cycles was defined as the protective performance of the coating.

[0039] Table 1 Performance Test Data of Ultrahard Wear-Resistant Protective Coating As can be seen from Table 1, the superhard wear-resistant protective coatings prepared in Examples 4-6 of this application have high bonding strength, hardness and protective performance.

[0040] The binder added to the protective coating prepared in this application is a multi-arm silanized macromolecular compound with a long-chain multifunctional group backbone derived from linoleic acid as its core. The long alkyl chain and siloxane groups provide excellent flexibility and film-forming properties, effectively buffering internal stress in the coating. The rigid conjugated structure of the benzene ring enhances the rigidity of the molecular chain, contributing to improved coating hardness. The phosphate ester groups form strong chemical bonds (such as POM) with the metal substrate surface, significantly improving the coating's bonding strength. Simultaneously, the terminal siloxy group (Si-OCH3) can hydrolyze and condense during the cladding process, forming a Si-O-Si three-dimensional network, and chemically coupling with inorganic components in the coating, further enhancing overall density and wear resistance. Furthermore, the CS bonds formed by the mercapto-alkene reaction stabilize the crosslinked network, preventing high-temperature cracking. The ester bond, acting as a bridge combining rigidity and flexibility, connects the flexible long alkyl chain with the rigid benzene ring, imparting rigidity and thermal stability to the molecular structure while simultaneously providing flexibility and internal stress buffering capacity due to the rotatability of the bond. Synergistic effects between functional groups enable the coating to possess both high hardness and strong bonding strength, adapting to the thermal stress environment of the cladding process.

[0041] In Comparative Example 3, the main reasons for the decrease in coating performance after replacing 6-aminohexanephosphoric acid in step S3 with an equimolar amount of (2-aminoethyl)phosphonate diethyl ester during the preparation of the binder are as follows: 6-aminohexanephosphoric acid contains free phosphonic acid groups and six long methylene spacer arms, which can rapidly dissociate under high-temperature cladding or interfacial conditions with trace amounts of moisture, forming strong polydentate coordination and MOP covalent bonds with the oxide layer on the metal substrate surface. At the same time, the long chain provides good stress buffering and flexible bridging, effectively improving the interfacial metallurgical bonding strength and anti-peeling ability. Conversely, the phosphate groups of (2-aminoethyl)phosphonate diethyl ester are completely esterified by ethoxy groups, losing the strong acidity and direct chemical coordination ability of the free acid. Under the high-temperature short-time conditions of cladding, the ester groups are difficult to fully hydrolyze or cleave into active phosphonate groups, and the carbon chain has only two methylene groups, resulting in large steric hindrance and weak extension ability, leading to a significant reduction in interfacial chemical bonding efficiency. Furthermore, esterification significantly weakens the polarity and hydrogen bonding ability of molecules, affects wettability and diffusivity in the molten state, and reduces the synergistic crosslinking effect with the Si-O-Si network. Ultimately, this impairs the cohesive strength, toughness, and crack propagation resistance of the coating, resulting in a decline in coating performance.

[0042] In Comparative Example 4, replacing 6-aminohexanephosphoric acid in step S3 with an equimolar amount of aminomethylphosphonic acid leads to a significant decrease in the adhesive performance. The core reason is as follows: the aminomethylphosphonic acid molecule has an extremely compact structure. Its phosphate group is connected to the amino group only through a methylene group. When this molecule is connected to the benzene ring core of intermediate 2 through the amino group, the distance between the phosphate group and the benzene ring is extremely close. In the molecular conformation, it is very easy to be stereo-encapsulated or spatially shielded by the rigid benzene ring unit, which significantly reduces the exposure of the phosphate group. This makes it difficult for the phosphate group to effectively contact and anchor to the surface of the metal substrate. Even under high-temperature cladding conditions, it is difficult to form a sufficiently strong interfacial chemical bond, thus leading to a decrease in performance.

[0043] 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 an ultra-hard wear-resistant protective coating, characterized in that, Includes the following steps: (1) The surface of the TC4 titanium alloy substrate is pretreated to obtain the treated substrate; (2) Mix titanium powder and graphene powder evenly, then add binder to obtain a mixed slurry; coat the mixed slurry evenly on the treated substrate surface, and dry to form a pre-placed powder layer; (3) Under argon protection, the pre-placed powder layer is scanned and clad, and then cooled to room temperature to obtain a protective coating clad on the TC4 titanium alloy substrate; The adhesive is prepared by the following method: S1: Methyl linoleate reacts with sodium hydride to form intermediate 1. S2: Intermediate 1 reacts with 4-(chloromethyl)benzyl alcohol to generate intermediate 2. S3: Intermediate 2 reacts with 6-aminohexanephosphoric acid to generate intermediate 3. S4: Intermediate 3 reacts with 3-mercaptopropyltrimethoxysilane to form a binder.

2. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step S2, the molar ratio of intermediate 1 to 4-(chloromethyl)benzyl alcohol is (1.05-1.1):

1.

3. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step S3, the molar ratio of intermediate 2 to 6-aminohexanephosphoric acid is (2.02-2.08):

1.

4. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step S4, the molar ratio of intermediate 3 to 3-mercaptopropyltrimethoxysilane is 1:(8.05-8.1).

5. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step (2), the mass ratio of titanium powder, graphene, and binder is 10:(1-2):(0.5-1).

6. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step (3), the cladding speed is 50-200 mm / min.

7. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step (3), the current intensity during cladding is 80-150A.

8. The method for preparing an ultra-hard wear-resistant protective coating according to claim 1, characterized in that, In step (3), the voltage during cladding is 14-18V.

9. A superhard wear-resistant protective coating, characterized in that, It is prepared by the method described in any one of claims 1-8.

10. The application of an ultrahard wear-resistant protective coating prepared by the preparation method according to any one of claims 1-8 in aero-engine blades.

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