A high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloy and its laser deposition preparation method.

Abstract

A high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloy and its laser deposition preparation method are disclosed, belonging to the field of composite material and coating preparation technology. The composite coating consists of a titanium alloy substrate layer, an intermediate toughness buffer layer, and a surface-strengthening film layer. The titanium alloy substrate layer refers to the surface of the titanium alloy. The surface-strengthening film layer is disposed on the titanium alloy substrate layer but away from its surface. The intermediate toughness buffer layer is disposed between the titanium alloy substrate layer and the surface-strengthening film layer. The titanium alloy substrate layer is composed of TC4 titanium alloy, the intermediate toughness buffer layer is composed of TiNi shape memory alloy, and the surface-strengthening film layer is composed of TC4 / B4C. The composite coating is prepared using a laser deposition method. The surface-strengthening film layer possesses comprehensive mechanical properties such as high hardness, high wear resistance, high corrosion resistance, and impact resistance, meeting the reliability manufacturing requirements of multifunctional / high-performance surface-strengthening films for typical parts under special service environments.

Description

Technical Field

[0001] This invention belongs to the field of composite material and coating preparation technology, specifically relating to a tough, interface-buffered, wear-resistant and corrosion-resistant titanium-based composite coating and its laser deposition preparation method. Background Technology

[0002] Titanium and titanium alloys possess numerous excellent properties, including high melting point, non-magnetic properties, low coefficient of thermal expansion, high specific strength and stiffness, good corrosion resistance, and resistance to bio-erosion, leading to their widespread application in aerospace, biomedical, and chemical engineering fields. However, the relatively low surface hardness, tendency to adhere, and poor wear resistance of titanium alloys severely limit their application in harsh load-bearing environments and corrosive media. Traditional modification techniques for improving surface wear resistance rely on significantly increasing surface hardness. The drawback of this method is that while improving wear resistance, it reduces impact and fatigue resistance, making it difficult to meet overall performance requirements. Since the failure behavior of titanium alloy components typically originates from the surface or surface layer, it is of great significance to improve the wear and corrosion resistance of titanium alloys through surface modification techniques, while simultaneously creating a novel modified layer with sufficient toughness and better compatibility with the matrix properties to prevent premature failure, without affecting the material's inherent properties.

[0003] Traditional surface strengthening technologies such as thermal diffusion, micro-arc oxidation, magnetron sputtering, cold / hot / plasma spraying, and chemical immersion plating can form functional films of a certain thickness on the surface of titanium and titanium alloys. These films enhance the wear resistance and corrosion resistance of the substrate surface to some extent, improving material performance and extending the service life of titanium alloy components. However, traditional surface modification technologies typically result in thin, porous, and high-stressed surface strengthening layers with significant differences in thermal expansion coefficients and elastic moduli between the strengthening layer and the substrate. This can lead to low bonding strength between the coating and the substrate, and even brittle cracking, crushing, and peeling. Once the modified layer is damaged, the released hard debris becomes abrasive particles, further exacerbating wear. Furthermore, single-layer binary and multi-component surface strengthening coatings offer limited protective functions, failing to meet the increasingly stringent service conditions demanding high wear resistance, high corrosion resistance, and other multifunctional / high-performance requirements for titanium alloy parts.

[0004] Laser melting deposition technology refers to the deposition of selected coating materials on the surface of a substrate using different filler methods. Laser irradiation causes the coating material and the substrate surface layer to melt simultaneously, resulting in rapid solidification and forming advantages such as extremely low dilution rate, minimal deformation, and excellent metallurgical bonding with the substrate material. This significantly improves the wear resistance, friction reduction, corrosion resistance, heat resistance, oxidation resistance, and functional properties of the substrate surface. Furthermore, based on service environment requirements, gradient-strengthened films of varying thicknesses and compositions, possessing both functional and performance characteristics, can be fabricated in two-dimensional and three-dimensional directions. This helps to simultaneously extend the service life and operating cycle of finished parts, avoiding the risk of part failure due to wear and corrosion.

[0005] In summary, there is an urgent need to develop a wear-resistant and corrosion-resistant composite coating for titanium alloys based on a tough interface buffer layer design and its laser deposition preparation method. This will enable the composite manufacturing of high wear-resistant, high corrosion-resistant, and high-strength and toughness reinforced coatings on the surface of titanium alloy parts. This is an important way to promote the development of surface modification and strengthening technology for high value-added parts in my country, and it is also a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the technical challenges of traditional surface modification techniques in preparing reinforced coatings, such as uncontrollable reinforced layer thickness, low bonding strength, high surface hardness but poor wear resistance, and the inability to achieve multifunctional composite coatings with both wear resistance and corrosion resistance, this invention aims to propose a high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloys and its laser deposition preparation method. This method offers advantages such as concentrated energy density, small heat-affected zone, intelligent control, flexible deposition material system, and customizable design. The prepared surface-reinforced coating possesses comprehensive mechanical properties including high hardness, high wear resistance, high corrosion resistance, and impact resistance, ultimately meeting the reliability manufacturing requirements of multifunctional / high-performance surface-reinforced coatings for typical parts under special service environments.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloy comprises a titanium alloy substrate layer, an intermediate toughness buffer layer, and a surface-strengthening film layer. The titanium alloy substrate layer refers to the surface of the titanium alloy. The surface-strengthening film layer is disposed on the titanium alloy substrate layer but away from its surface. The intermediate toughness buffer layer is disposed between the titanium alloy substrate layer and the surface-strengthening film layer. The titanium alloy substrate layer is composed of TC4 titanium alloy, the intermediate toughness buffer layer is composed of TiNi shape memory alloy, and the surface-strengthening film layer is composed of TC4 / B4C. TC4 / B4C refers to a mixture or doping of micro / nano-scale mismatched B4C ceramic particles with TC4 alloy powder. Specifically, the mass fraction of B4C particles with a particle size range of 53-150 μm is 50%~75%, and the mass fraction of B4C particles with a particle size range of 5-10 nm is 25%~50%. The preparation method is as follows: micron-sized and nano-sized B4C ceramic particles are added to TC4 alloy powder at a certain mass fraction. First, mechanical premixing is performed using a V-type powder mixer, and then wet mixing is performed using a high-energy ball mill. To avoid the powder from heating up and oxidizing during the high-energy ball milling process, anhydrous ethanol is used as the wet mixing medium. After vacuum drying, a uniformly mixed ceramic particle-reinforced TC4 / B4C composite powder is obtained. The amount of B4C added accounts for 10% to 50% of the mass fraction of the TC4 / B4C composite powder.

[0009] Furthermore, when the service environment requires 45HRC < surface modification layer hardness < 55HRC, the mass fraction of B4C ceramic particles is 10%-30%; when 55HRC < surface modification layer hardness < 70HRC, the mass fraction of B4C ceramic particles is 30%~50%.

[0010] Furthermore, when the surface modification layer requires comprehensive mechanical properties such as high hardness, high wear resistance, high corrosion resistance, and impact resistance, the surface modification composite coating can be a TC4 substrate layer - TC4 / B4C surface strengthening layer (…). Figure 1 Example 1, Example 4 Figure 2 Alternatively, it can be a "soft-hard alternating" TC4 substrate layer - TiNi toughness layer - TC4 / B4C surface strengthening layer - TiNi toughness layer - TC4 / B4C surface strengthening layer (the number of alternations can be set according to actual needs). Figure 1 Example 3), furthermore, the TiNi tough alloy layer can be designed as a lattice structure with impact resistance and energy absorption effects. Figure 1 Example 2).

[0011] This invention also provides a method for preparing a high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloys, comprising the following steps:

[0012] (1) The surface of the TC4 titanium alloy substrate is mechanically polished according to the set polishing path to remove the surface oxide film and improve the bonding strength between the substrate and the cladding layer; after polishing, it is cleaned to remove the surface debris and oil.

[0013] (2) TC4 alloy powder and B4C ceramic powder are weighed according to the mass fraction of B4C in TC4 / B4C composite powder of 10%-50%, and then mechanically mixed in a V-type powder mixer at 80 rpm for 1-2 h. Then, the premixed powder is put into a ball mill for wet high-energy ball milling. The ratio of zirconia ceramic balls to metal powder balls is 1:1, the speed is 400 rpm, the mixing time is 20-24 h, the mixing medium is anhydrous ethanol, and Ar atmosphere is used for protection. In order to further improve the uniformity of powder mixing, a multi-channel powder feeding system can also be used to transport TC4 alloy powder and B4C ceramic powder online in real time.

[0014] (3) Dry the TC4 / B4C composite powder and TiNi alloy powder separately in a vacuum heating box at a temperature of 60 ℃~150 ℃ for 2 h~4 h under Ar atmosphere protection.

[0015] (4) Using laser melting deposition technology, a dried TiNi alloy coating or a TiNi alloy coating with a lattice structure is deposited on the surface of the treated TC4 titanium alloy to obtain an intermediate toughness buffer layer. During deposition, the defocusing amount is set to -4 mm to +4 mm, the laser power is 1300 W to 3500 W, the scanning speed is 5 mm / s to 15 mm / s, the powder feed rate is 0.7 r / min to 2.5 r / min, the overlap rate is 30% to 50%, the carrier gas flow rate is 2.5 L / min to 4.7 L / min, the spot diameter is 2 mm to 5 mm, the oxygen content is ≤30 ppm, and the substrate preheating temperature is 200 ℃ to 500 ℃. Then, dried TC4 / B4C composite powder is deposited on the surface of the intermediate toughness buffer layer as a surface strengthening film layer. During deposition, the defocusing amount is set to 0 mm to +2 mm, the laser power is 1200 W to 2500 W, the scanning speed is 7 mm / s to 12 mm / s, and the powder feed rate is 1.0 r / min to 2.0 r / min. With a speed of r / min, an overlap ratio of 40%~50%, a carrier gas flow rate of 2.5 L / min~4.5 L / min, a spot diameter of 3 mm~5 mm, an oxygen content of ≤50ppm, a substrate preheating temperature of 200 ℃~300 ℃, and 1~6 deposition layers, a composite coating with high wear resistance, high corrosion resistance, and impact resistance is obtained.

[0016] In step (4), a "soft-hard alternation" method can also be used to deposit a TiNi intermediate toughness layer and a TC4 / B4C reinforcement layer on the TC4 substrate; wherein, the TiNi toughness alloy layer can also be designed as a lattice structure with impact resistance and energy absorption effect. Figure 3 ).

[0017] Furthermore, based on the requirements of the service environment, in order to improve the surface quality of the composite coating, the coating surface is subjected to laser remelting or intelligent polishing; the laser remelting power is 500 W~1000 W, the scanning speed is 5 mm / s~10 mm / s, and the scanning interval is 2 mm; the intelligent polishing process uses a high-hardness cubic boron nitride grinding head for polishing, the polishing speed is 1000 rpm~2000 rpm, and the grinding amount is 100 μm~300 μm.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) This invention provides a design and laser deposition method for a high wear resistance, high corrosion resistance and impact resistance composite coating suitable for titanium alloys. The expansion coefficient of the TiNi alloy intermediate toughness buffer layer is small and the bonding strength is high. After deposition, it can achieve synergistic deformation with the substrate. During the friction process, the TiNi transition layer with porous lattice structure and "soft and hard alternation" has a certain deformable space during the impact process. Its surface micro-peaks can withstand large contact stress, induce large amount of recoverable deformation, effectively increase the contact area, and can greatly reduce stress concentration compared with hard surface film layer with poor deformation capacity. Local stress concentration can also induce phase transformation of adjacent tissues, so that stress can be released in time. Through the synergistic cooperation of high hardness surface strengthening film layer with specific composition and intermediate toughness buffer layer with different structure, the high toughness composite coating has good wear resistance, corrosion resistance and impact resistance and high mechanical properties, which can effectively improve the reliability and safety of titanium alloy parts in special service environments.

[0020] (2) The laser melting deposition preparation method proposed in this invention has the advantages of intelligent control, flexible deposition materials, controllable gradient composition, online real-time powder mixing, uniform composite powder composition, and the ability to realize fine manufacturing of porous lattice structure, which ensures the custom design of intermediate toughness buffer layer and the high quality and high performance manufacturing of surface strengthening film. Attached Figure Description

[0021] Figure 1 The figure shows a schematic diagram of the high wear resistance / high corrosion resistance and toughening composite coating structure of titanium alloy described in the embodiment of the present invention. The labels in the figure represent: A is the TC4+B4C surface strengthening layer, B is the TiNi alloy intermediate toughening layer, C is the TC4 alloy base layer, D is the TiNi alloy layer with a lattice structure, and E is the strengthening layer with a gradient change in the mass fraction of B4C.

[0022] Figure 2 The surface morphology of the strengthening and toughening composite coating of the titanium alloy described in this invention;

[0023] Figure 3 The macroscopic morphology of the TiNi alloy toughness buffer specimens with different hollow ratio lattice structures described in this invention;

[0024] Figure 4 This refers to the high wear-resistant reinforced layer with a gradient change in B4C mass fraction as described in the embodiments of the present invention;

[0025] Figure 5 The effect of gradient composition transition on the coating's sensitivity to crack defects;

[0026] Figure 6 The effect of gradient component transition mode on improving wear resistance. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] A high-wear-resistant, high-corrosion-resistant, and toughening composite coating for titanium alloys, such as Figure 4 As shown. To reduce the differences in mechanical properties, physical properties, and chemical composition between the high-hardness reinforced film layer on the upper surface and the lower substrate, this high-performance composite coating includes: depositing a first TiNi alloy coating as an intermediate toughness buffer layer on top of the TC4 substrate; depositing a second TC4+10%B4C reinforced layer; depositing a third TC4+20%B4C reinforced layer; depositing a fourth TC4+30%B4C reinforced layer; and depositing a fifth TC4+40%B4C reinforced layer, ultimately forming a high-hardness, high-wear-resistant, and toughened composite coating system with a gradient composition of B4C mass fraction. Specifically, the added B4C particles with a particle size range of 53-150 μm account for 75% of the mass fraction, and the B4C particles with a particle size range of 5-10 nm account for 25% of the mass fraction.

[0029] The preparation method of the high-hardness, high-wear-resistant, and toughened composite coating with a gradient composition of B4C mass fraction includes the following specific steps:

[0030] (1) The surface of TC4 titanium alloy was mechanically polished using 400# and 600# abrasive belts. After polishing, it was cleaned in an ultrasonic cleaner containing anhydrous ethanol to remove the grinding debris and oil stains on the surface. The TC4 titanium alloy substrate with the oxide film removed by grinding and cleaned was placed in a flexible Ar gas sealed chamber. Then, the three-dimensional model data of the sample to be deposited was drawn by Solidworks software and input into the control system. The part model was adaptively sliced ​​from bottom to top and a serpentine reciprocating scanning path was planned. Then, the sample was prepared for layer-by-layer deposition additive manufacturing.

[0031] (2) TC4 alloy powder and B4C ceramic powder were weighed according to the mass fraction of B4C in TC4 / B4C composite powder of 10%, 20%, 30% and 40%, respectively. They were first mechanically mixed in a V-type powder mixer at a speed of 80 rpm for 2 h. Then the premixed powder was put into a ball mill for wet high-energy ball milling. The ratio of zirconia ceramic balls to metal powder balls was 1:1 (ball:material = 1:1), the speed was 400 rpm, the mixing time was 24 h, the mixing medium was anhydrous ethanol, and Ar atmosphere was used for protection.

[0032] (3) The TC4 / B4C composite powder and TiNi alloy powder were dried separately in a vacuum heating box at a temperature of 120 °C for 3 h under Ar atmosphere protection.

[0033] (4) By inputting commands into the control system, the powder-feeding laser head is moved to both ends of the processing table (i.e., the starting position of the workpiece printing). The powder feeding device and protective gas control valve are turned on for pre-powder feeding and gas protection. When the oxygen content detector shows that the oxygen content is ≤30ppm, the laser is turned on and the high-energy laser beam is transmitted to the laser head through the optical fiber. The dried metal powder is sprayed on the titanium alloy metal substrate above it along the planned path. The preset shape is deposited according to the model data. After several depositions, a deposition sample of a certain height is obtained. The details are as follows:

[0034] A coaxial powder-fed laser melting deposition technique was employed. First, TiNi alloy was deposited onto the surface of a treated TC4 titanium alloy substrate to prepare an intermediate toughness buffer layer. The deposition parameters were: defocusing depth +4 mm, laser power 2500 W, scanning speed 10 mm / s, powder feed rate 1.0 r / min, overlap ratio 50%, carrier gas flow rate 4.7 L / min, spot diameter 4 mm, oxygen content ≤50 ppm, and substrate preheating temperature 300 ℃. Since B4C ceramic powder increases the absorption rate of the composite powder to the laser, a gradient power variation deposition strategy was adopted. The laser power was 2500 W for the first layer with 10% B4C content, 2300 W for 20% B4C content, 2100 W for 30% B4C content, and 1900 W for 40% B4C content. The scanning speed was 10 mm / s, the powder feed rate was 1.0 r / min, and the thickness of each layer was approximately 0.5 mm. The composite coating exhibits high wear resistance, high corrosion resistance, and impact resistance. Specifically, based on service environment requirements, to improve the surface quality of the composite coating and reduce machining processes, the surface is laser-remelted followed by intelligent polishing. The laser remelting power is 800 W, the scanning speed is 7 mm / s, the spot diameter is 4 mm, and the scanning spacing is 2 mm. The intelligent polishing process uses a high-hardness cubic boron nitride grinding head at 1500 rpm and a grinding depth of 200 μm, thereby obtaining a smooth, finely finished surface-strengthened coating. The overlap ratio is 50%, the carrier gas flow rate is 4.7 L / min, the spot diameter is 4 mm, the oxygen content is ≤30 ppm, the substrate preheating temperature is 200 ℃, and four layers of each composite component are deposited.

[0035] When directly laser cladding high-volume-fraction B4C particle composite powder, cracking of the cladding layer occurs due to the difference in elastic modulus and coefficient of thermal expansion between the cladding layer and the matrix material. Therefore, a gradient composition transition method is adopted. Each cladding layer can be achieved by simply changing the rotation speed of the powder feeding hopper, with a gradual change of 10%-20%-30%-40%.

[0036] like Figure 5 As shown, coatings with a direct deposition of 40% B4C by mass fraction exhibit cracks, while those using a gradient composition transition method show no cracks on the coating surface. Figure 6 As shown, the gradient composition transition method has a significant impact on improving wear resistance. The smaller the friction coefficient, the better the wear resistance. The average friction coefficient of the TC4 titanium alloy substrate is 0.391, while the average friction coefficient of the gradient composition transition method is 0.278, which improves the wear resistance by 28.9%.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite coating for high wear resistance, high corrosion resistance, and enhanced toughness of titanium alloy, characterized in that, It is composed of a titanium alloy substrate layer, an intermediate toughness buffer layer, and a surface strengthening film layer; the titanium alloy substrate layer refers to the surface of the titanium alloy, the surface strengthening film layer is disposed on the titanium alloy substrate layer and away from the surface of the titanium alloy substrate, and the intermediate toughness buffer layer is disposed between the titanium alloy substrate layer and the surface strengthening film layer; wherein, the intermediate toughness buffer layer is composed of TiNi shape memory alloy, and the surface strengthening film layer is composed of TC4 / B4C, where TC4 / B4C refers to the mixture or doping of micro / nano-scale mismatched B4C ceramic particles with TC4 alloy powder. In the micro / nano-scale mismatched B4C ceramic particles, the mass fraction of B4C particles with a particle size range of 53-150 μm is 50%~75%, and the mass fraction of B4C particles with a particle size range of 5-10 nm is 25%~50%. The preparation method of the TC4 / B4C is as follows: micron-sized and nano-sized B4C ceramic particles are added to TC4 alloy powder according to the mass fraction. First, mechanical premixing is performed using a V-type powder mixer, and then wet mixing is performed using a high-energy ball mill. Anhydrous ethanol is used as the wet mixing medium. After vacuum drying, a uniformly mixed ceramic particle-reinforced TC4 / B4C composite powder is obtained. The amount of B4C added accounts for 10%~50% of the mass fraction of the TC4 / B4C composite powder.

2. The high wear-resistant, high corrosion-resistant, and toughened composite coating for titanium alloy according to claim 1, characterized in that, On a titanium alloy substrate, a TiNi intermediate toughness buffer layer and a TC4 / B4C surface strengthening film layer are alternately arranged.

3. The high wear-resistant, high corrosion-resistant, and toughened composite coating for titanium alloy according to claim 1, characterized in that, The TiNi intermediate toughness buffer layer is set with a lattice structure.

4. The method for preparing the high wear-resistant, high corrosion-resistant, and toughened composite coating of titanium alloy according to any one of claims 1-3, characterized in that, Follow these steps: (1) The surface of the TC4 titanium alloy substrate is mechanically polished according to the set polishing path to remove the surface oxide film and improve the bonding strength between the substrate and the cladding layer; after polishing, it is cleaned to remove the surface debris and oil. (2) Mix TC4 alloy powder and B4C ceramic powder according to the mass fraction ratio; then put the premixed powder into a ball mill for wet high-energy ball milling and mixing. The ratio of zirconia ceramic balls to metal powder balls is 1:1, the rotation speed is 400 rpm, the mixing time is 20h~24h, the mixing medium is anhydrous ethanol, and Ar atmosphere is used for protection. (3) Dry the TC4 / B4C composite powder and TiNi alloy powder separately in a vacuum heating chamber under Ar atmosphere protection; (4) Using laser melting deposition technology, a dried TiNi alloy coating or a TiNi alloy coating with a lattice structure is deposited on the surface of the treated TC4 titanium alloy to obtain an intermediate toughness buffer layer; then, dried TC4 / B4C composite powder is deposited on the surface of the intermediate toughness buffer layer as a surface strengthening film.

5. The method for preparing the high wear-resistant, high corrosion-resistant, and toughened composite coating of titanium alloy according to claim 4, characterized in that, In step (2), after weighing according to the mass fraction of B4C in TC4 / B4C composite powder of 10% to 50%, mechanical mixing is carried out in a V-type powder mixer at a speed of 80 rpm for 1 to 2 hours.

6. The method for preparing the high wear-resistant, high corrosion-resistant, and toughened composite coating of titanium alloy according to claim 4, characterized in that, In step (4), the process parameters for depositing TiNi alloy powder on the surface of TC4 titanium alloy are as follows: the defocusing amount during deposition is set to -4mm to +4mm, the laser power is 1300W to 3500W, the scanning speed is 5mm / s to 15mm / s, the powder feeding rate is 0.7r / min to 2.5r / min, the overlap rate is 30% to 50%, the carrier gas flow rate is 2.5L / min to 4.7L / min, the spot diameter is 2mm to 5mm, the oxygen content is ≤30ppm, and the substrate preheating temperature is 200℃ to 500℃.

7. The method for preparing a high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloys according to claim 4, characterized in that, In step (4), the process parameters for depositing TC4 / B4C composite powder on the surface of the intermediate toughness buffer layer are as follows: the defocusing amount is set to 0mm~+2mm, the laser power is 1200W~2500W, the scanning speed is 7mm / s~12mm / s, the powder feeding rate is 1.0r / min~2.0r / min, the overlap rate is 40%~50%, the carrier gas flow rate is 2.5L / min~4.5L / min, the spot diameter is 3mm~5mm, the oxygen content is ≤50ppm, the substrate preheating temperature is 200℃~300℃, and the number of deposition layers is 1~6 layers.

8. The method for preparing a high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloys according to claim 4, characterized in that, In step (4), an alternating deposition method is used to deposit a TiNi intermediate toughness layer and a TC4 / B4C reinforcement layer on the TC4 substrate.

9. The method for preparing a high-wear-resistant, high-corrosion-resistant, and toughened composite coating for titanium alloys according to claim 4, characterized in that, The coating surface is subjected to laser remelting or intelligent polishing; the laser remelting power is 500W~1000W, the scanning speed is 5mm / s~10mm / s, and the scanning interval is 2mm; the intelligent polishing process uses a high-hardness cubic boron nitride grinding head for polishing, the polishing speed is 1000rpm~2000rpm, and the grinding amount is 100μm~300μm.

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