A TiN / GO composite ceramic coating with self-lubricating function and its preparation method

Abstract

The present invention discloses a self-lubricating TiN / GO composite ceramic coating, which is located on the surface of a TC4 substrate and is prepared from a mixed powder comprising 95-99 wt.% TiN and 1-5 wt.% GO. The preparation method comprises pre-treating the TiN and GO mixed powder; preparing a pre-set powder slurry from the pre-treated TiN and GO mixed powder; and cladding the pre-set powder slurry onto the pre-treated TC4 substrate surface using a broadband laser cladding process to form a TiN / GO composite ceramic coating on the TC4 substrate surface. The TiN / GO composite ceramic coating of the present invention exhibits excellent wear resistance and friction reduction properties, reducing friction losses in the wear system.

Description

Technical Field

[0001] The present invention belongs to the field of titanium alloy modification, and in particular relates to a TiN / GO composite ceramic coating with a self-lubricating function and a preparation method thereof. Background Art

[0002] TC4 alloy has poor wear resistance, which can easily lead to severe wear of the grinding pair at the femoral head of titanium alloy artificial joints, causing bone dissolution and aseptic loosening, which has become a key issue restricting its long-term healthy use. It needs to be surface modified and modified to improve its wear resistance. Titanium nitride (TiN) is a ceramic with good biocompatibility, corrosion resistance and wear resistance, and is a good human implant material. A large number of studies have shown that titanium alloys modified with TiN surface coatings not only have the good mechanical properties of titanium alloys, but also exhibit excellent wear resistance at the friction interface. Therefore, using surface modification technology to modify the surface of titanium alloys to obtain a ceramic coating with good wear resistance is an effective method to reduce the surface wear of titanium alloys.

[0003] However, TiN's extremely hard properties and high coefficient of friction can cause severe wear of the mating material (acetabular cup liner) at the femoral head interface, generating more wear debris, leading to osteolysis and aseptic loosening. These problems can harm the host's health and limit the use of TiN ceramic coatings as human implants. Therefore, the development of a self-lubricating ceramic coating at the femoral head interface of artificial joints to reduce the friction coefficient of the joint and the generation of wear debris, thereby ensuring the long-term, healthy and stable use of artificial joints, is a pressing technical challenge. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a TiN / GO composite ceramic coating and a preparation method thereof.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A TiN / GO composite ceramic coating is provided. The TiN / GO composite ceramic coating is located on the surface of a TC4 substrate and is prepared from a mixed powder consisting of 95-99 wt.% TiN and 1-5 wt.% GO.

[0007] The above-mentioned TiN / GO composite ceramic coating is preferably clad on the surface of the TC4 substrate using broadband laser cladding technology.

[0008] The TiN / GO composite ceramic coating preferably comprises primarily TiN, GO, Ti3Al, α-Ti, TiCN, and TiV. The TC4 substrate and powder are melted together to undergo a chemical reaction, with the Ti, Al, and V elements reacting to form AlTi3 and TiV phases, resulting in a good metallurgical bond between the coating and the coating.

[0009] The above-mentioned TiN / GO composite ceramic coating preferably has a thickness of 200-300 μm.

[0010] As a general inventive concept, the present invention also provides a method for preparing the above-mentioned TiN / GO composite ceramic coating, comprising the following steps:

[0011] (1) Pretreatment of TiN and GO mixed powder;

[0012] (2) preparing a pre-set powder slurry from the pretreated TiN and GO mixed powders;

[0013] (3) A broadband laser cladding process is used to clad the pre-set powder layer slurry on the surface of the pretreated TC4 substrate to form a TiN / GO composite ceramic coating on the surface of the TC4 substrate.

[0014] In the above preparation method, preferably, in step (1), the TiN powder in the TiN and GO mixed powder has a particle size of 1-10 μm and a purity greater than 99.9%, and the GO powder has a thickness of 1-10 nm and a purity greater than 99.9%.

[0015] In the above-mentioned preparation method, preferably, in step (1), the specific process of pre-treating the TiN and GO mixed powders is as follows: first, the TiN powder and GO powder are dried separately, and then the dried TiN powder and GO powder are ball-milled for 12-24 hours, and then the ball-milled mixed powder is added to anhydrous ethanol, ultrasonically treated for 10-30 minutes, and finally placed in a vacuum drying oven at 50-100°C for 12-24 hours.

[0016] In the above-mentioned preparation method, preferably, in step (2), the specific preparation process of the pre-set powder slurry is: adding the pretreated TiN and GO mixed powder to a polyvinyl alcohol aqueous solution with a concentration of 1-3wt.%, stirring for about 5-10 minutes, and ultrasonically dispersing for 5-10 minutes to obtain a pre-set powder slurry, wherein the concentration of the pre-set powder slurry is 0.3-0.5g / mL.

[0017] In the above preparation method, preferably, in step (3), the process parameters of the broadband laser cladding process include: laser power of 1500-2100W, laser scanning speed of 150-210mm·min-1 The length of the spot size is 15-20mm, the width is 1-3mm, and the flow rate of the protective gas argon is 5-15L·min -1 .

[0018] In the above preparation method, preferably, in step (3), the pretreatment process of the TC4 substrate includes placing the TC4 substrate in a mixture of deionized water and ethanol, ultrasonically cleaning it for 20-30 minutes, and then drying it in a vacuum dryer at 50-100°C for 12-24 hours.

[0019] Graphene oxide is non-biotoxic and exhibits good lubrication properties over a wide temperature range. By introducing GO powder and utilizing a broadband laser cladding process, the present invention can further improve the wear resistance of the TiN coating and reduce the friction coefficient of the TiN coating, thereby reducing the friction coefficient of the joint-to-grinding pair and the generation of wear debris, thereby achieving the goal of long-term, healthy, and stable use of artificial joints.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] (1) In the TiN / GO composite ceramic coating of the present invention, by introducing TiN powder and utilizing the wear resistance of TiN, a broadband laser cladding process is used to clad the coating on the TC4 surface, thereby ensuring the wear resistance of the coating; and by combining GO powder and utilizing the low friction performance of GO, a broadband laser cladding process is used to clad the coating together with TiN on the TC4 surface, thereby reducing the friction coefficient of the coating. The two work together to ensure that the composite ceramic coating has good wear resistance and friction reduction performance, thereby reducing the friction loss of the wear system.

[0022] (2) The TiN / GO composite ceramic coating of the present invention is suitable for application on artificial titanium alloy joints to prevent excessive wear of the artificial joints from generating a large amount of wear debris, thereby inducing bone dissolution and aseptic loosening.

[0023] (3) The TiN / GO composite ceramic coating of the present invention is prepared by a broadband laser cladding process, which is easy to implement, has good reliability, simple maintenance, good versatility, low production cost, and is convenient for large-scale production. In addition, compared with the circular spot process, it has higher processing efficiency, better coating quality and bonding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the TiN / GO composite ceramic coating of the present invention.

[0025] Figure 2 This is a photo of the TiN / GO composite ceramic coating prepared in Example 1 of the present invention.

[0026] Figure 3XRD patterns of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example tested by X-ray diffractometer.

[0027] Figure 4 Figure 3 is the cross-sectional micromorphology of the TiN / GO composite ceramic coating prepared in the examples of the present invention and the TiN ceramic coating prepared in the comparative example observed by SEM electron microscope. In the figure, a, b, c, and d are the cross-sectional micromorphologies of the ceramic coatings prepared in comparative example 1, example 1, example 2, and example 3, respectively.

[0028] Figure 5 The cross-sectional local micromorphology of the TiN / GO composite ceramic coating prepared in Example 1 of the present invention observed by SEM electron microscope.

[0029] Figure 6 This is an EDS point map of the cross-sectional local micromorphology of the TiN / GO composite ceramic coating prepared in Example 1 of the present invention tested by an X-ray energy spectrometer.

[0030] Figure 7 Vickers hardness indentation on the cross section of the TiN / GO composite ceramic coating prepared in an embodiment of the present invention tested by a Vickers hardness tester.

[0031] Figure 8 The Vickers hardness average value curve on the cross section of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example tested by a Vickers hardness tester.

[0032] Figure 9 The friction coefficients of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example when grinding against Si3N4 balls were tested using a friction and wear testing machine.

[0033] Figure 10 The friction coefficients of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example when grinding against TC4 balls were tested using a friction and wear testing machine.

[0034] Figure 11 The friction coefficients of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example when grinding against UHMWPE balls were tested using a friction and wear testing machine.

[0035] Figure 12 The macroscopic morphologies of the TiN / GO composite ceramic coating prepared in the embodiment of the present invention and the TiN ceramic coating prepared in the comparative example when worn in SBF (simulated body fluid) solution were observed by an optical profilometer.

[0036] Figure 13The wear micromorphologies of the TiN / GO composite ceramic coating prepared in the examples of the present invention and the TiN ceramic coating prepared in the comparative example, observed by SEM electron microscope, when grinding against Si3N4 balls in SBF (simulated body fluid) solution. In the figure, a, b, c, and d are the wear micromorphologies of the ceramic coatings prepared in comparative example 1, example 1, example 2, and example 3, respectively.

[0037] Figure 14 The wear micromorphologies of the TiN / GO composite ceramic coating prepared in the examples of the present invention and the TiN ceramic coating prepared in the comparative example, observed by SEM electron microscope, when ground against TC4 balls in SBF (simulated body fluid) solution. In the figure, a, b, c, and d are the wear micromorphologies of the ceramic coatings prepared in comparative example 1, example 1, example 2, and example 3, respectively.

[0038] Figure 15 The wear micromorphologies of the TiN / GO composite ceramic coating prepared in the examples of the present invention and the TiN ceramic coating prepared in the comparative example, observed by SEM electron microscope, when ground against UHMWPE balls in SBF (simulated body fluid) solution. In the figure, a, b, c, and d are the wear micromorphologies of the ceramic coatings prepared in comparative example 1, example 1, example 2, and example 3, respectively.

[0039] Figure 16 These are actual photos of the TiN ceramic coatings prepared in Comparative Examples 2, 3, and 4 of the present invention.

[0040] Figure 17 These are actual photos of the TiN / GO composite ceramic coatings prepared in Examples 4 and 5 of the present invention.

[0041] Legend:

[0042] 1. TC4 substrate; 2. TiN / GO composite ceramic coating. DETAILED DESCRIPTION

[0043] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0044] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0045] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0046] Example 1:

[0047] A TiN / GO composite ceramic coating with self-lubricating function according to the present invention has a structural schematic diagram as shown in FIG. Figure 1 As shown, the TiN / GO composite ceramic coating 2 is located on the surface of the TC4 substrate 1. The thickness of the TiN / GO composite ceramic coating is 200 μm. The TiN / GO composite ceramic coating is composed of a mixed powder with a mass content of 97 wt.% TiN and a mass content of 3 wt.% GO, which is clad on the surface of the TC4 substrate using broadband laser cladding technology.

[0048] The preparation method of the TiN / GO composite ceramic coating of this embodiment includes the following steps:

[0049] (1) Coating raw material preparation and pretreatment

[0050] Micron-sized TiN powder (purity ≥ 99.9%, average particle size 1 μm) and nanometer-thick GO powder (purity ≥ 99.9%, average thickness 5 nm) were ball-milled in a horizontal planetary ball mill. The TiN addition amount was 97 wt.%, the GO addition amount was 3 wt.%, and the ball mill speed was 150 rpm. -1 , the ball milling time is 12h.

[0051] After ball milling, the mixed powder was placed in 300 mL of anhydrous ethanol, vibrated in an ultrasonic vibration device for 30 min, and finally dried in a vacuum drying oven at 70°C for 12 h.

[0052] (2) Substrate pretreatment

[0053] The TC4 sheets were cut into substrates measuring 20 mm x 30 mm x 4 mm using a wire-cutting machine. The surfaces of the TC4 substrates were polished with 80-grit SiC sandpaper to remove the surface oxide film. The polished TC4 substrates were then ultrasonically cleaned in deionized water and ethanol for 30 minutes and dried in a vacuum dryer at 70°C for 12 hours.

[0054] (3) Preparation before cladding

[0055] Use an electronic analytical balance to weigh 0.3 g of the mixed powder prepared in step (1), add it to 1 mL of a 2 wt.% polyvinyl alcohol aqueous solution, stir for 5 minutes, and then place it in an ultrasonic dispersion table for ultrasonic dispersion for 5 minutes to prepare a pre-set powder slurry.

[0056] The TC4 substrate treated in step (2) was placed on a constant temperature heating table at 80°C, the pre-set powder slurry was evenly spread on the surface of the substrate, and then placed in a vacuum dryer at 70°C for 24 hours to form a pre-set powder.

[0057] (4) Broadband laser cladding

[0058] A broadband laser cladding system was used to clad the pre-set powder on the surface of the TC4 substrate to form a TiN / GO composite ceramic coating. The cladding process parameters of the coating were: laser power of 1800W, laser scanning speed of 180mm min -1 , the spot size is 18mm×2mm, and the flow rate of protective gas argon is 10L·min -1 .

[0059] The macro-microstructure test results of the TiN / GO composite ceramic coating sample prepared in this example are as follows: Figure 2-Figure 6 As shown, Figure 2 The middle left picture is a photo of the TiN / GO composite ceramic coating sample, where A is the TiN / GO composite ceramic coating and B is the TC4 substrate; Figure 3 The XRD pattern of the TiN / GO composite ceramic coating prepared in this embodiment shows that the TiN / GO composite ceramic coating in this embodiment mainly contains TiN, GO, Ti3Al, α-Ti, TiCN and TiV. Due to the high temperature of laser cladding, the substrate and powder melt together and a chemical reaction occurs. The Ti, Al and V elements react to form AlTi3 and TiV phases, forming a good metallurgical bond between the coating and the substrate. Figure 4 This is the SEM electron microscope image of the TiN / GO composite ceramic coating prepared in this example, showing a good metallurgical bond between the ceramic coating and the pure titanium substrate.

[0060] The cross-sectional local micromorphology and X-ray spectrometer test results of the TiN / GO composite ceramic coating sample prepared in this embodiment are shown in FIG. Figure 5 、 6 As shown in the figure, it can be seen that the granular crystals in the TiN / GO composite ceramic coating are TiN and the lamellar crystals are GO.

[0061] The Vickers hardness test results of the TiN / GO composite ceramic coating sample prepared in this embodiment are as follows: Figure 7-Figure 8 As shown in the figure, it can be seen that the average microhardness of the ceramic coating is 1256±139HV 0.2 , greater than the microhardness of the substrate 340HV 0.2 .

[0062] Friction and wear testing:

[0063] The prepared sample block containing the TiN / GO composite ceramic coating was placed in deionized water and ethanol, and after being cleaned in an ultrasonic cleaner for 30 minutes, the cleaned sample block was placed in a 60°C vacuum dryer and dried for 8 hours. Then, a friction test was performed on it using a friction and wear testing machine, and the surface coating of the sample was polished with 80-600 mesh SiC sandpaper, and then a friction test was performed in an SBF solution environment. The grinding balls were Si3N4 balls, TC4 balls, and ultra-molecular weight polyethylene (UHMWPE) balls, respectively. The load was 2500g and the test time was 1 hour. The tribological performance test results of the TiN / GO composite ceramic coating prepared in this embodiment are shown in FIG. Figures 9 to 16 As shown in the figure, the ceramic coating prepared in this example has better wear resistance and a lower friction coefficient than the TC4 ball and UHMWPE ball in Comparative Example 1. These results demonstrate that the TiN / GO composite ceramic coating of the present invention has excellent wear resistance and good friction reduction properties, and has promising application prospects.

[0064] Comparative Example 1:

[0065] This comparative example is a TiN ceramic coating, which differs from Example 1 in that GO is not introduced. The specific preparation process includes the following steps:

[0066] (1) Substrate pretreatment

[0067] The TC4 plate was cut into substrates with a size of 20 mm × 30 mm × 4 mm using a wire cutting machine. The surface of the TC4 substrate to be prepared was polished with 80-mesh SiC sandpaper to remove the surface oxide film. The polished TC4 specimen was placed in deionized water and ethanol, cleaned in an ultrasonic cleaner for 30 minutes, and then dried in a vacuum dryer at 70°C for 12 hours.

[0068] (2) Preparation before cladding

[0069] 0.3 g of TiN powder (purity ≥ 99.9%, average particle size 1 μm) was weighed using an electronic analytical balance and added to 1 mL of a 2 wt.% polyvinyl alcohol aqueous solution. After stirring for 5 min, the mixture was placed on an ultrasonic dispersion table and ultrasonically dispersed for 5 min to obtain a pre-set powder slurry.

[0070] The TC4 substrate prepared in step (1) was placed on a constant temperature heating table at 80°C, the pre-set powder slurry was evenly spread on the surface of the TC4 substrate, and then placed in a vacuum dryer at 70°C for drying for 12 hours.

[0071] (3) Broadband laser cladding

[0072] A broadband laser cladding system was used to clad the pre-set powder on the surface of the TC4 substrate to form a TiN ceramic coating. The cladding process parameters were: laser power of 1800W, laser scanning speed of 180mm min -1 , the spot size is 18mm×2mm, and the flow rate of protective gas argon is 10L·min -1 .

[0073] The friction and wear test was the same as in Example 1. The friction and wear test results of the TiN ceramic coating prepared in this comparative example are shown in FIG. Figures 9-15 As shown in the figure, it can be seen that the friction coefficient of the TiN ceramic coating in this comparative example is greater than that of the TiN / GO composite ceramic coating, which shows that the introduction of GO can reduce the friction coefficient of the coating during friction and wear, and can also reduce the wear amount of the friction system when grinding with TC4 balls and ultra-molecular-weight polyethylene balls.

[0074] Comparative Example 2, Comparative Example 3 and Comparative Example 4:

[0075] Comparative Examples 2-4 are all TiN / GO composite ceramic coatings. The difference from Example 1 is that a circular spot laser is used to prepare the coating in step (4). Other specific preparation processes are the same as those in Example 1.

[0076] A circular spot laser cladding system was used to clad the pre-set powder on the surface of the TC4 substrate to form a TiN / GO composite ceramic coating. The cladding process parameters were as follows: laser power as shown in Table 1, laser scanning speed of 180 mm min -1 , the spot size is 1 mm, and the flow rate of protective gas argon is 10 L min -1 .

[0077] Table 1 Laser power parameters used in comparative examples 2, 3, and 4

[0078] Comparative Example 2 Comparative Example 3 Comparative Example 4 Laser power parameters 150W 200W 250W

[0079] The TiN / GO composite ceramic coating samples prepared in Comparative Examples 2-4 are as follows Figure 16 As shown in the figure, it can be seen that when using a circular spot laser, the TiN / GO ceramic coating prepared in the comparative example exhibits the following characteristics: (1) when the power is 150W, the TiN / GO composite ceramic coating cannot be clad on the surface of the TC4 substrate; (2) when the power is 200W, the TiN / GO composite ceramic coating clad on the surface of the TC4 substrate has poor bonding performance and severe coating peeling; (3) when the power is 250W, the TiN / GO composite ceramic coating clad at a higher laser power is of poor quality and has obvious pits on the coating surface. From this, it can be indirectly seen that the broadband laser cladding process used in the present invention to prepare the TiN / GO composite ceramic coating has higher processing efficiency, better coating quality and bonding performance than the circular spot process.

[0080] Example 2 and Example 3:

[0081] The difference between Examples 2 and 3 and Example 1 is that the contents of TiN powder and GO powder in step 1 are different, as shown in Table 2. The other preparation processes are exactly the same as those in Example 1.

[0082] Table 1 Mixed powder content parameters used in Examples 1, 2, and 3

[0083]

[0084] Table 2 Wear amount of wear system (ball + coating) of embodiment and comparative example 1 (10 -2 mm 3 min -1 )

[0085]

[0086] The friction and wear properties of the TiN / GO composite ceramic coatings prepared in Examples 2 and 3 are as follows: Figures 9-15 As shown in Table 3, when grinding against TC4 and UHMWPE, Example 1 significantly reduces the wear loss and friction coefficient of the wear system (ball + coating) compared to the other comparative examples and examples. Within the scope of the present invention, self-lubricating ceramic coatings can be prepared with the addition of different amounts of GO powder, and Example 1 achieves the greatest reduction in friction coefficient.

[0087] Comparative Example 5 and Comparative Example 6:

[0088] The difference between Comparative Examples 5 and 6 and Example 1 is that more GO is added to the mixed powder in step 1. The mixed powder parameters are shown in Table 4. The other preparation processes are exactly the same as those in Example 1.

[0089] Table 4 Mixed powder content parameters used in Example 1, Comparative Example 4, and Comparative Example 5

[0090]

[0091] The TiN / GO composite ceramic coating samples prepared in Comparative Examples 5 and 6 are as follows: Figure 17 As shown in the figure, the TiN / GO composite ceramic coatings prepared in Comparative Examples 5 and 6 exhibit uneven surfaces and deteriorated coating quality as the GO content increases. This indicates that the GO content should be within the range of the present invention and should not be too high, otherwise the coating quality will deteriorate.

[0092] In summary, the technical solution of the present invention introduces an appropriate amount of GO powder and TiN powder for mixing, and uses broadband laser cladding to form a TiN / GO composite ceramic coating with self-lubricating function on the surface of the TC4 substrate, thereby reducing the friction and wear of the coating and having a friction-reducing function, ensuring that the TiN / GO composite ceramic coating has good long-term application.

Claims

1. A TiN / GO composite ceramic coating with self-lubricating function, characterized in that: The TiN / GO composite ceramic coating is applied to artificial titanium alloy joints; the TiN / GO composite ceramic coating is located on the surface of a TC4 substrate, and the TiN / GO composite ceramic coating is prepared from a mixed powder consisting of 95 to 99 wt.% TiN and 1 to 5 wt.% GO; the TiN / GO composite ceramic coating is clad on the surface of the TC4 substrate using broadband laser cladding technology.

2. The TiN / GO composite ceramic coating according to claim 1, wherein The TiN / GO composite ceramic coating contains TiN, GO, Ti3Al, α-Ti, TiCN and TiV.

3. The TiN / GO composite ceramic coating according to claim 1, wherein The thickness of the TiN / GO composite ceramic coating is 200-300 μm.

4. A method for preparing a TiN / GO composite ceramic coating according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Pretreatment of TiN and GO mixed powder; (2) preparing a pre-set powder slurry from the pre-treated TiN and GO mixed powders; (3) The broadband laser cladding process is used to clad the pre-set powder slurry on the surface of the pretreated TC4 substrate to form a TiN / GO composite ceramic coating on the surface of the TC4 substrate.

5. The preparation method according to claim 4, wherein In step (1), the TiN powder in the TiN and GO mixed powder has a particle size of 1-10 μm and a purity greater than 99.9%, and the GO powder has a thickness of 1-10 nm and a purity greater than 99.9%.

6. The preparation method according to claim 4, wherein In step (1), the specific process of pretreatment of TiN and GO mixed powder is as follows: first, the TiN powder and GO powder are dried separately, and then the dried TiN powder and GO powder are ball-milled for 12-24 h, and then the ball-milled powder is added to anhydrous ethanol and ultrasonically treated for 10-30 min, and finally placed in a vacuum drying oven at 50-100 °C for 12-24 h.

7. The preparation method according to claim 4, wherein In step (2), the specific preparation process of the pre-set powder slurry is: adding the pre-treated TiN and GO mixed powder to a 1-3 wt.% concentration of polyvinyl alcohol aqueous solution, stirring for 5-10 minutes, and ultrasonically dispersing for 5-10 minutes to obtain the pre-set powder slurry.

8. The preparation method according to claim 4, wherein In step (3), the process parameters of broadband laser cladding process include: laser power of 1500-2100 W, laser scanning speed of 150-210 mm·min -1 The spot size is 15-20 mm in length, 1-3 mm in width, and the flow rate of protective gas argon is 5-15 L·min -1 .

9. The preparation method according to claim 4, wherein In step (3), the pretreatment process of the TC4 substrate includes placing the TC4 substrate in a mixture of deionized water and ethanol, ultrasonically cleaning it for 20-30 minutes, and then drying it in a vacuum dryer at 50-100°C for 12-24 hours.

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