Titanium-steel composite plate structure for ocean engineering and preparation method of titanium-steel composite plate structure

Abstract

The invention discloses a titanium-steel composite plate structure for ocean engineering and a preparation method of the titanium-steel composite plate structure, and belongs to the technical field of ocean engineering materials.The composite plate comprises a titanium plate, a steel sheet and a gradient functional layer arranged between the titanium plate and the steel sheet, and the gradient functional layer is composed of a titanium side MOF enrichment layer, a component gradual change transition layer and a steel side enhancement layer; the surface of a titanium plate is subjected to nanoscale rough oxidation treatment, a nano-pillar array structure is constructed on the surface of a steel sheet, high-strength combination of a heterogeneous metal interface and collaborative improvement of marine corrosion resistance are achieved, and a gradient coating technology of electrostatic spraying, aerosol spraying and slit coating is adopted in the preparation process; and the titanium-steel composite plate for ocean engineering is prepared by matching vacuum hot-pressing bonding and cooling technologies.

Description

Technical Field

[0001] The present invention belongs to the field of metal layered composite materials for marine engineering equipment, and in particular relates to a titanium-steel composite plate structure for marine engineering and a preparation method thereof. Background Art

[0002] In the field of marine engineering, due to the long-term exposure to harsh environments with high salt, high humidity, strong corrosion, and complex loads, extremely high requirements are placed on the comprehensive performance of materials. Titanium alloys have received widespread attention in marine engineering due to their excellent corrosion resistance and good comprehensive mechanical properties, but they are relatively expensive and have relatively insufficient rigidity. Although steel materials have high strength and low cost, they are very prone to corrosion in marine environments, leading to structural failure. The composite process of titanium and steel to prepare titanium-steel composite plates can achieve the complementary advantages of the two materials. They have both the corrosion resistance of titanium and the high strength and low cost of steel. They have broad application prospects in marine engineering structures such as ship hulls and offshore platforms.

[0003] Titanium and steel have significantly different physical and chemical properties, and direct composites face the following challenges: The significant difference in thermal expansion coefficients between titanium and steel makes traditional hot working (hot rolling, explosive welding) prone to thermal stresses at the interface, leading to delamination or cracking. The different atomic arrangements between titanium and steel make it difficult for atoms at the interface to form an effective metallurgical bond, making it a source of corrosion or fracture. At high temperatures, titanium and steel readily form brittle intermetallic compounds, and these hard-brittle phases significantly reduce the toughness of the interface, leading to composite plate failure. Explosive welding interfaces are prone to wavy deformation and microcracks, and the process is poorly controllable, making uniform composites over large areas difficult to achieve. Explosions generate high-intensity noise, vibration, and smoke, requiring remote locations for operation and hampering production continuity by weather conditions (humidity and wind speed). Hot rolling is difficult to achieve high-quality composites of titanium, copper, aluminum, and other materials with steel, as oxidation and interdiffusion at high temperatures exacerbate the formation of brittle phases. Interfacial oxidation during high-temperature rolling generates impurity layers such as TiO2 and FeO, weakening the bond. Prolonged heat retention promotes the growth of brittle phases. Traditional interfaces lack corrosion protection design. Chloride ions penetrate along bonding defects to induce galvanic corrosion, accelerate substrate rust, and microbial attachment further deteriorates the interface. The mutated interface cannot relieve thermal expansion mismatch stress. Under long-term thermal cycling, interface shear stress accumulates, causing delamination failure. Traditional explosion and hot rolling methods have significant shortcomings in interface brittleness control, geometric adaptability, environmental compatibility, and cost efficiency. Especially for heterogeneous metal composites such as titanium-steel, interface metallurgical incompatibility becomes a core challenge. Therefore, how to construct a suitable transition layer and reinforcement layer at the composite interface to improve the interface bonding strength, corrosion resistance, and fatigue resistance is the key to the preparation of high-performance titanium-steel composite plates. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention discloses a titanium-steel composite plate structure for marine engineering and a preparation method thereof, which belongs to the field of marine engineering material technology. The composite plate includes a titanium plate, a steel sheet and a gradient functional layer arranged between the two, and the gradient functional layer is composed of a titanium side MOF enrichment layer, a composition gradient transition layer and a steel side reinforcement layer. By performing nano-scale rough oxidation treatment on the surface of the titanium plate and constructing a nano-column array structure on the surface of the steel sheet, the high-strength bonding of the heterogeneous metal interface and the synergistic improvement of marine corrosion resistance are achieved. The preparation process adopts a gradient coating process of electrostatic spraying, aerosol spraying and slit coating, and cooperates with vacuum hot pressing bonding and rapid cooling technology to prepare a titanium-steel composite plate for marine engineering; the present invention solves the problems of low interface bonding strength and poor corrosion resistance of heterogeneous metal connections in marine engineering equipment, and can be widely used in marine platforms, ship structures and other fields.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] A method for preparing a titanium-steel composite plate structure for marine engineering includes a titanium plate, a steel sheet, and a gradient functional layer disposed between the two; the gradient functional layer is composed of a titanium-side enriched layer bonded to the titanium plate, a compositionally graded transition layer located in the middle, and a steel-side reinforcement layer bonded to the steel sheet. The preparation process uses a gradient coating process of electrostatic spraying, aerosol spraying, and slit coating, and finally vacuum hot pressing bonding to prepare a titanium-steel composite plate for marine engineering, wherein:

[0007] The titanium side enrichment layer comprises a MOF loaded with nano-boron powder and SiC nanowires and graphene oxide particles dispersed therein;

[0008] The composition-gradient transition layer comprises a mixed phase of a titanium side functional composite material, a steel side functional composite material and Ni@SiO2 microcapsules;

[0009] The steel side reinforcement layer comprises a composite of ZrO2 nanoparticles, graphene oxide particles, polyacrylonitrile fibers and silica sol.

[0010] Preferably, a nano-rough oxide layer TiO2 is provided on the surface of the titanium plate, Fe3O4 nanocrystals are deposited on the surface of the steel sheet, the titanium side enrichment layer fills the pores of the nano-rough oxide layer TiO2 of the titanium plate, and the steel side reinforcement layer forms an anchoring bond with the surface of the steel sheet.

[0011] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0012] Step (1): roughening and oxidizing the surface of the titanium plate to form a nano-scale rough oxide layer, and etching and Fe3O4 nanocrystal deposition on the surface of the steel sheet to form a nanocolumn array structure;

[0013] Step (2): preparing a titanium side enrichment layer slurry containing a MOF-based filler, a steel side reinforcement layer slurry containing a ceramic particle reinforcement phase, and an intermediate transition layer slurry containing a gradient component;

[0014] Step (3): coating a titanium side enrichment layer on the surface of the titanium plate, coating a steel side reinforcement layer on the surface of the steel sheet, and coating an intermediate transition layer with a gradient composition between the two to form a three-layer gradient functional layer;

[0015] Step (4): Laminating the coated titanium plate with the steel sheet, achieving interface metallurgical bonding through vacuum hot pressing, and obtaining a titanium-steel composite plate after cooling and cleaning.

[0016] Preferably, in step (1), the surface of the titanium plate is roughened by sandblasting, wherein Al2O3 sand particles are sprayed at a pressure of 0.4-0.6 MPa, the sandblasting distance is 8-12 cm, and the sandblasting time is 25-35 s; the oxidation treatment is carried out by constant voltage electrolysis, wherein the titanium plate is used as the anode and the platinum sheet is used as the cathode, and electrolysis is carried out in a 0.4-0.6 M oxalic acid solution at a voltage of 18-22 V for 25-35 min.

[0017] Preferably, in step (1), the steel sheet surface is etched by laser processing, with a laser wavelength of 10-64 nm, a power of 15-25 W, a scanning speed of 400-600 mm / s, and an etching spacing of 80-120 μm; the nanocrystal deposition is carried out by a hydrothermal method, and the mass ratio of FeCl3·6H2O, NaAc, and ethylene glycol in the precursor solution is 0.8-1.2:8-10:40-42, and the temperature is kept at 170-190°C for 5-7 hours.

[0018] Preferably, the preparation of the titanium side enrichment layer slurry in step (2) comprises: mixing UiO-66-NH2 at a vacuum degree of 10 -2 -10 - 1 Pa, immersed in nano-boron powder ethanol suspension, pressurized to 1.5-2.5MPa and maintained at pressure for 0.5-1.5h, dried and mixed with SiC nanowires, GO, PEG-400 and anhydrous ethanol and ball milled. The mass ratio of UiO-66-NH2, nano-boron powder, SiC nanowires, GO, PEG-400 and anhydrous ethanol is 7-9:0.3-0.5:1-3:4-6:9-11:75-85.

[0019] Preferably, the titanium side enrichment layer in step (3) is coated by electrostatic spraying, with a coating voltage of 18-22 kV, a nozzle distance of 13-17 cm from the substrate, a propulsion rate of 0.4-0.6 mL / min, and spraying in multiple times on a 45-55°C heating platform, with a coating thickness of 40-60 μm.

[0020] Preferably, in step (3), the intermediate transition layer is coated by aerosol spraying, and the slurry components are controlled by dynamic proportioning of dual pumps. The titanium side slurry containing 50%-60% MOF-based fillers is injected in the first 10-15 minutes, and then gradually switched to the transition slurry containing 25%-35% MOF-based fillers in the next 20-25 minutes, forming a gradient interface layer with a thickness of 100±10μm.

[0021] Preferably, in step (3), the steel side reinforcement layer is coated using a slit coating process with a coating gap of 40-60 μm and a coating speed of 40-60 mm / s. The steel sheet is preheated to 55-65°C, and the coating direction is perpendicular to the nanocolumn array so that the ZrO2 particles are oriented and arranged. The coating thickness is 140-160 μm.

[0022] Preferably, the vacuum hot pressing conditions in step (4) are: vacuum degree <10⁻³Pa, heating rate 4-6°C / min, keeping at 290-310°C for 25-35min, keeping at 440-460°C for 15-25min, and pressure 4-6MPa.

[0023] Beneficial technical effects:

[0024] The present application provides a titanium-steel composite plate structure for marine engineering and its preparation method. The structure comprises the following steps: superimposing a coated titanium plate with a steel sheet and subjecting the plate to vacuum hot pressing to achieve interfacial metallurgical bonding. During the vacuum hot pressing process, MOF decomposes to form amorphous ZrO2 and C. Nano-boron powder reacts with the porous TiO2 layer on the titanium plate surface to form TiB2. ZrO2 reacts with nano-boron powder to form ZrB2. TiB2 / ZrB2 form a covalent-metal bond mixed crystal. Ti / Zr and nano-boron powder are strongly covalently bonded, blocking the formation of the FeTi / Fe2Ti brittle phase while exhibiting high hardness and a certain degree of toughness. During the vacuum hot pressing, the SiO2 shell ruptures to release Ni particles. Graphene oxide is reduced to remove oxygen-containing groups and transform into a pure carbon layer. Under Ni catalysis, carbon atoms rearrange to form graphene crystals, which grow vertically into a graphene array structure under the action of the hot compressive stress / temperature field. The graphene array separates the titanium / steel dissimilar metals, cutting off the electron migration path and inhibiting the formation of electrochemical corrosion cells. Seawater contains abundant chloride ions, the primary anionic component and a key factor in the corrosion of marine engineering materials. The graphene array structure can block the diffusion of chloride ions. The graphene base chemically bonds to Fe₃O₄ nanocrystals, catalyzed by nickel to form Fe-C bonds. During vacuum hot pressing, the PAN molecular chains release gases such as HCN and NH₃, carbonizing to form amorphous carbon. Subsequently, graphitization occurs under nickel catalysis. The graphene bonds to ZrO₂ nanoparticles via CO-Zr bonds and chemically adsorbs to Fe atoms on the steel substrate surface via C-Fe bonds. TiB₂ / ZrB₂ ceramic particles fill the TiO₂ pores on the titanium surface. Ni-catalyzed graphene sheets cover the interface, and the vertical graphene arrays formed by PAN carbonization form a physical barrier. The titanium side bonds to the ceramic layer via Ti-O-Zr and Ti-B bonds; the steel side bonds to the reinforcement layer via Fe-Ni and Fe-C bonds. The intermediate transition layer forms a Ti-Zr-Ni-Fe interfacial metallic bond formed by diffusion of Ni particles following the rupture of the Ni@SiO₂ microcapsules. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a SEM image of a titanium-steel composite plate for marine engineering.

[0026] Figure 2 This is a product appearance diagram of a titanium-steel composite plate for marine engineering. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the following examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above-mentioned method concepts of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0028] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to be limiting of the application.

[0029] As used in this application, the singular forms "for," "a," "any," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0030] In addition, if the terms "first" and "second" appear in this application, they are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0031] In the first aspect, the present application provides a titanium-steel composite plate structure for marine engineering, comprising a titanium plate, a steel sheet, and a gradient functional layer arranged between the two; the gradient functional layer is composed of a titanium side enrichment layer bonded to the titanium plate, a compositionally gradient transition layer located in the middle, and a steel side reinforcement layer bonded to the steel sheet, wherein: the titanium side enrichment layer contains UiO-66-NH2 loaded with nano-boron powder and SiC nanowires and graphene oxide dispersed therein; the compositionally gradient transition layer includes a mixed phase of titanium side slurry, steel side slurry, and Ni@SiO2 microcapsules, and the MOF content decreases along the titanium → steel direction; the steel side reinforcement layer includes a composite solution formed on the surface of a steel substrate, including ZrO2 nanoparticles, graphene oxide (GO), polyacrylonitrile fibers, and silica sol.

[0032] In one feasible implementation scheme, a nano-scale rough oxide layer is provided on the surface of the titanium plate, and a nano-column array structure is provided on the surface of the steel sheet. The titanium side enrichment layer is filled in the pores of the nano-scale rough oxide layer of the titanium plate, and the steel side reinforcement layer forms an anchoring bond with the nano-column array structure of the steel sheet.

[0033] In one feasible implementation scheme, the nanoscale rough oxide layer is a TiO2 porous layer with a thickness of 4-6 μm; the diameter of the pillars in the nanopillar array structure is 40-60 nm and the height is 70-90 nm.

[0034] In a second aspect, the present application provides a method for preparing a titanium-steel composite plate structure for marine engineering, comprising the following steps: (1) surface pretreatment: roughening and oxidizing the surface of the titanium plate to form a nano-scale rough oxide layer, and etching and nanocrystal deposition on the surface of the steel sheet to form a nano-column array structure; (2) slurry preparation: preparing a titanium side enrichment layer slurry containing MOF-based fillers, a steel side reinforcement layer slurry containing ceramic particle reinforcement phase, and an intermediate transition layer slurry containing gradient components; (3) gradient coating: coating the titanium side enrichment layer on the surface of the titanium plate, coating the steel side reinforcement layer on the surface of the steel sheet, and coating an intermediate transition layer with a gradient composition between the two to form a three-layer gradient functional layer; (4) vacuum hot pressing bonding: overlapping the coated titanium plate and the steel sheet, achieving interface metallurgical bonding through vacuum hot pressing, and obtaining a titanium-steel composite plate after rapid cooling and cleaning.

[0035] In one feasible implementation scheme, in step (1), the surface of the titanium plate is roughened by sandblasting, with Al2O3 sand particles sprayed at a pressure of 0.4-0.6 MPa, a sandblasting distance of 8-12 cm, and a sandblasting time of 25-35 s; the oxidation treatment is carried out by constant voltage electrolysis, with the titanium plate as the anode and the platinum sheet as the cathode, in a 0.4-0.6 M oxalic acid solution, at a voltage of 18-22 V for 25-35 min.

[0036] In terms of a feasible implementation scheme, in step (1), the steel sheet surface is etched by laser processing, with a laser wavelength of 10-64nm, a power of 15-25W, a scanning speed of 400-600mm / s, and an etching spacing of 80-120μm; the nanocrystal deposition is carried out by a hydrothermal method, and the mass ratio of FeCl3·6H2O, NaAc, and ethylene glycol in the precursor solution is 0.8-1.2:8-10:40-42, and the temperature is kept at 170-190℃ for 5-7h.

[0037] In a feasible embodiment, the preparation of the titanium side enrichment layer slurry in step (2) includes: UiO-66-NH2 is placed in a vacuum of 10 -2 -10 -1 Pa, immersed in nano-boron powder ethanol suspension, pressurized to 1.5-2.5MPa and maintained at pressure for 0.5-1.5h, dried and mixed with SiC nanowires, GO, PEG-400 and anhydrous ethanol, and ball milled. The mass ratio of each component is 7-9:0.3-0.5:1-3:4-6:9-11:75-85.

[0038] In one feasible implementation scheme, the titanium side enrichment layer in step (3) is coated by electrostatic spray coating, with a coating voltage of 18-22 kV, a nozzle distance of 13-17 cm from the substrate, a propulsion rate of 0.4-0.6 mL / min, and multiple sprayings on a 45-55°C heating platform, with a coating thickness of 40-60 μm.

[0039] As for a feasible implementation scheme, the intermediate transition layer in step (3) is coated by aerosol spraying, and the slurry components are controlled by dynamic proportioning of dual pumps. In the first 10-15 minutes, a titanium side slurry containing 50%-60% MOF-based filler is injected, and in the next 20-25 minutes, it is gradually switched to a transition slurry containing 25%-35% MOF-based filler, forming a gradient interface layer with a thickness of 100±10μm.

[0040] In terms of a feasible implementation scheme, in step (3), the steel side reinforcement layer adopts a slit coating process with a coating gap of 40-60 μm and a coating speed of 40-60 mm / s. The steel sheet is preheated to 55-65°C. The coating direction is perpendicular to the nanocolumn array so that the ZrO2 particles are arranged in a directional manner. The coating thickness is 140-160 μm.

[0041] In terms of a feasible implementation scheme, the vacuum hot pressing conditions in step (4) are as follows: vacuum degree <10-3Pa, heating rate 4-6℃ / min, keeping at 290-310℃ for 25-35min and 440-460℃ for 15-25min, pressure 4-6MPa; water quenching immediately after hot pressing, cooling rate 130-170℃ / s, and ultrasonic cleaning after quenching to remove residual impurities on the surface.

[0042] The following will describe in detail a titanium-steel composite plate structure for marine engineering and a preparation method thereof provided by the present application in combination with different embodiments.

[0043] Example 1:

[0044] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0045] 1. A titanium plate was fixed to the working chamber of a sandblaster. 100μm Al2O3 sand particles were sprayed uniformly at a pressure of 0.5MPa from a distance of 10cm for 30s. After roughening, the titanium plate was ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove surface dust and then dried. The titanium plate served as the anode, a platinum sheet as the cathode, and a 0.5M oxalic acid solution as the electrolyte. Electrolysis was performed at a constant voltage of 20V for 30 minutes. The electrolyte temperature was controlled at 25±2°C to produce a 5±0.5μm thick porous TiO2 layer. After oxidation, the titanium plate was rinsed three times with deionized water and dried in an 80°C oven for 1 hour.

[0046] 2. Using a laser wavelength of 50 nm, power of 20 W, scanning speed of 500 mm / s, and etching pitch of 100 μm, nanopillar arrays with a diameter of 50 nm and a height of 80 nm were fabricated on a steel surface. After etching, the steel sheet was ultrasonically cleaned with acetone for 15 minutes to remove surface oil. FeCl₃・6H₂O was added to ethylene glycol and stirred until dissolved. NaAc was added and stirred for 30 minutes until uniform. The mass ratio of FeCl₃・6H₂O:NaAc:ethylene glycol was 1.00:9.00:41. The steel sheet was placed vertically in a polytetrafluoroethylene reactor and the prepared solution was slowly poured into it. The mixture was incubated at 180°C for 6 hours, cooled naturally, removed from the heat, rinsed with deionized water, and dried at 60°C for 2 hours.

[0047] 3. Preparation of titanium side slurry: Take UiO-66-NH2 and place it in a vacuum impregnation tank, evacuate to 10-2Pa, inject 0.5wt% nano-boron powder ethanol suspension (ultrasonic dispersion for 30min, power 300W), pressurize to 2MPa and hold the pressure for 1h, release the pressure and dry at 60℃ for 2h, ball mill the boron-loaded MOF and SiC nanowires, add GO, PEG-400, and anhydrous ethanol and ball mill. In the titanium side slurry, the mass ratio of UiO-66-NH2, nano-boron powder, SiC nanowires, GO, PEG-400, and anhydrous ethanol is 8:0.4:2:5:10:80

[0048] 4. Preparation of steel side slurry: GO was dissolved in 16 times the mass of deionized water and ultrasonically dispersed for 30 minutes; 0.04 times the mass of GO polyacrylonitrile fiber and 2 times the mass of GO ZrO2 nanoparticles were added, and ultrasonication was continued for 2 hours (200W, 40kHz); 10 times the mass of GO silica sol was added and magnetic stirring was performed for 1 hour.

[0049] 5. Gradient transition layer slurry (intermediate layer): 20% nickel powder ethanol slurry + 10% hydrolyzate (TEOS:EtOH:H2O:ammonia mass ratio of 1.00:3.34:0.95:0.48). Stir at 25°C for 30 minutes, then centrifuge and wash (8000 rpm × 5 minutes). Add the remaining 90% hydrolyzate dropwise (0.5 mL / min), and react in a 40°C water bath for 2 hours (magnetic stirring at 200 rpm). Mix the titanium side slurry with the steel side slurry (mass ratio of 3:5), add 2wt% Ni@SiO2 microcapsules, and stir until evenly distributed.

[0050] 6. MOF-enriched layer on the titanium side: Voltage 20 kV, nozzle distance 15 cm from the titanium plate, propulsion rate 0.5 mL / min, atomization pressure 0.2 MPa. The titanium plate was placed horizontally on a heated platform (50°C), and sprayed at a constant speed (5 mm / s). Spraying was performed in three passes (with 10-minute drying intervals between each pass).

[0051] 7. Intermediate Transition Layer: Aerosol injection parameters were: 0.3 MPa pressure, 100 μm nozzle diameter, 10 mm distance from the substrate, and a slurry flow rate of 1 mL / min. Gradient Control: Dynamically proportioning with a dual syringe pump was employed. The titanium side slurry (50% MOF) was injected for the first 10 minutes, followed by a gradual switch to the transition layer slurry (30% MOF) over the next 20 minutes, creating a uniform, gradient interface.

[0052] 8. Steel side reinforcement layer: Slit coating parameters are: a 50 μm gap, a coating speed of 50 mm / s, and the steel sheet is preheated to 60°C to reduce solvent residue. The coating direction is perpendicular to the nanopillar array on the steel surface to ensure vertical alignment of the ZrO2 particles. The coating thickness is 150 μm.

[0053] 9.Thermocompression bonding and post-processing

[0054] The coated titanium plate and the steel sheet are overlapped, and 1mm thick elastic graphite pads are placed on the upper and lower sides, and fixed in a stainless steel clamp to ensure uniform interface pressure. After the hot pressing is completed, the clamp is removed and immersed in 25°C deionized water (the liquid level is 5cm higher than the sample), and the cooling rate is 150±20°C / s. After quenching, the sample is ultrasonically cleaned with ethanol for 10 minutes to remove residual graphite debris on the surface, and then dried and sealed to preserve the titanium-steel composite plate. Hot pressing parameters: vacuum degree: <10-3Pa; heating program: 5°C / min to 300°C, keep warm for 30 minutes, continue to heat up to 450°C, keep warm for 20 minutes; pressure control: 5MPa, a titanium-steel composite plate structure for marine engineering is obtained, such as Figure 1 and Figure 2 shown.

[0055] Example 2:

[0056] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0057] 1. A titanium plate was fixed to the working chamber of a sandblaster. 100μm Al2O3 sand particles were sprayed uniformly at a pressure of 0.4MPa from a distance of 8cm for 25s. After roughening, the titanium plate was ultrasonically cleaned with anhydrous ethanol for 10min to remove surface dust and then air-dried for later use. The titanium plate served as the anode, a platinum sheet as the cathode, and a 0.4M oxalic acid solution as the electrolyte. Electrolysis was performed at a constant voltage of 18V for 25min. The electrolyte temperature was controlled at 25±2°C, producing a 5±0.5μm thick porous TiO2 layer. After oxidation, the titanium plate was rinsed three times with deionized water and oven-dried at 80°C for 1h.

[0058] 2. Using a laser wavelength of 50 nm, power of 20 W, scanning speed of 500 mm / s, and etching pitch of 100 μm, nanopillar arrays with a diameter of 40 nm and a height of 70 nm were fabricated on a steel surface. After etching, the steel sheet was ultrasonically cleaned with acetone for 15 minutes to remove surface oil. FeCl₃・6H₂O was added to ethylene glycol and stirred until dissolved. NaAc was added and stirred for 30 minutes until uniform. The mass ratio of FeCl₃・6H₂O:NaAc:ethylene glycol was 0.8:8:40. The steel sheet was placed vertically in a polytetrafluoroethylene reactor and the prepared solution was slowly poured into it. The steel sheet was heated at 170°C for 7 hours, cooled naturally, removed from the reactor, rinsed with deionized water, and dried at 60°C for 2 hours.

[0059] 3. Titanium side slurry preparation: UiO-66-NH2 was placed in a vacuum impregnation tank and evacuated to 10-2 Pa. A 0.5 wt% nanoboron powder suspension in ethanol (ultrasonic dispersion for 30 minutes at 300 W) was added. The pressure was increased to 1.5 MPa and maintained for 1 hour. After depressurization, the tank was dried at 60°C for 2 hours. The boron-loaded MOF and SiC nanowires were ball-milled. GO, PEG-400, and anhydrous ethanol were then added and ball-milled. The mass ratio of UiO-66-NH2, nanoboron powder, SiC nanowires, GO, PEG-400, and anhydrous ethanol in the titanium side slurry was 7:0.3:1:4:9:75.

[0060] 4. Preparation of steel side slurry: GO was dissolved in 16 times the mass of deionized water and ultrasonically dispersed for 30 minutes; 0.04 times the mass of GO polyacrylonitrile fiber and 2 times the mass of GO ZrO2 nanoparticles were added, and ultrasonication was continued for 2 hours (200W, 40kHz); 10 times the mass of GO silica sol was added and magnetic stirring was performed for 1 hour.

[0061] 5. Gradient transition layer slurry (intermediate layer): 20% nickel powder ethanol slurry + 10% hydrolyzate (TEOS:EtOH:H2O:ammonia mass ratio of 1.00:3.34:0.95:0.48). Stir at 25°C for 30 minutes, then centrifuge and wash (8000 rpm × 5 minutes). Add the remaining 90% hydrolyzate dropwise (0.5 mL / min), and react in a 40°C water bath for 2 hours (magnetic stirring at 200 rpm). Mix the titanium side slurry with the steel side slurry (mass ratio of 3:5), add 2wt% Ni@SiO2 microcapsules, and stir until evenly distributed.

[0062] 6. MOF-enriched layer on the titanium side: Voltage 18 kV, nozzle distance 13 cm from the titanium plate, propulsion rate 0.4 mL / min, atomization pressure 0.2 MPa. The titanium plate was placed horizontally on a heated platform (40°C), and sprayed at a constant speed (5 mm / s). Spraying was performed in three passes (with 10-minute drying intervals between each pass).

[0063] 7. Intermediate Transition Layer: Aerosol injection parameters were: 0.3 MPa pressure, 100 μm nozzle diameter, 10 mm distance from the substrate, and a slurry flow rate of 1 mL / min. Gradient Control: Dynamically proportioning with a dual syringe pump was employed. The titanium side slurry (50% MOF) was injected for the first 10 minutes, followed by a gradual switch to the transition layer slurry (25% MOF) over the next 20 minutes, creating a uniform, gradient interface.

[0064] 8. Steel side reinforcement layer: Slit coating parameters are: a coating gap of 40 μm, a coating speed of 40 mm / s, and the steel sheet is preheated to 55°C to reduce solvent residue. The coating direction is perpendicular to the nanopillar array on the steel surface to ensure vertical alignment of the ZrO2 particles. The coating thickness is 140 μm.

[0065] 9.Thermocompression bonding and post-processing

[0066] The coated titanium plate and the steel sheet are overlapped, and 1mm thick elastic graphite pads are placed on the upper and lower surfaces, and fixed in a stainless steel clamp to ensure uniform interface pressure. After the hot pressing is completed, the clamp is removed and immersed in 25°C deionized water (the liquid level is 5cm higher than the sample), and the cooling rate is 150±20°C / s. After quenching, the sample is ultrasonically cleaned with ethanol for 10 minutes to remove residual graphite debris on the surface, and then dried and sealed for preservation of the titanium-steel composite plate. Hot pressing parameters: vacuum degree: <10-3Pa; heating program: 5°C / min to 290°C, keep warm for 30 minutes, continue to heat up to 440°C, keep warm for 20 minutes; pressure control: 5MPa, a titanium-steel composite plate structure for marine engineering is obtained, such as Figure 1 and Figure 2 shown.

[0067] Example 3:

[0068] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0069] 1. A titanium plate was fixed to the working chamber of a sandblaster. 100μm Al2O3 sand particles were sprayed uniformly at a pressure of 0.6MPa from a distance of 12cm for 35 seconds. After roughening, the titanium plate was ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove surface dust and then dried. The titanium plate served as the anode, a platinum sheet as the cathode, and a 0.6M oxalic acid solution as the electrolyte. Electrolysis was performed at a constant voltage of 22V for 35 minutes. The electrolyte temperature was controlled at 25±2°C to produce a 5±0.5μm thick porous TiO2 layer. After oxidation, the titanium plate was rinsed three times with deionized water and oven-dried at 80°C for 1 hour.

[0070] 2. Using a laser wavelength of 50 nm, power of 25 W, scanning speed of 500 mm / s, and etching pitch of 100 μm, a nanopillar array with a diameter of 60 nm and a height of 90 nm was fabricated on a steel surface. After etching, the steel sheet was ultrasonically cleaned with acetone for 15 minutes to remove surface oil. FeCl₃・6H₂O was added to ethylene glycol and stirred until dissolved. NaAc was added and stirred for 30 minutes until uniform. The mass ratio of FeCl₃・6H₂O:NaAc:ethylene glycol was 1.2:10:42. The steel sheet was placed vertically in a polytetrafluoroethylene reactor and the prepared solution was slowly poured into it. The steel sheet was heated at 190°C for 5 hours, cooled naturally, removed from the reactor, rinsed with deionized water, and dried at 60°C for 2 hours.

[0071] 3. Titanium side slurry preparation: UiO-66-NH2 was placed in a vacuum impregnation tank and evacuated to 10-2 Pa. A 0.5 wt% nanoboron powder suspension in ethanol (ultrasonic dispersion for 30 minutes at 300 W) was then injected. The pressure was increased to 2.5 MPa and maintained for 1 hour. After depressurization, the tank was dried at 60°C for 2 hours. The boron-loaded MOF and SiC nanowires were ball-milled. GO, PEG-400, and anhydrous ethanol were then added and ball-milled. The mass ratio of UiO-66-NH2, nanoboron powder, SiC nanowires, GO, PEG-400, and anhydrous ethanol in the titanium side slurry was 9:0.5:3:6:11:85.

[0072] 4. Preparation of steel side slurry: GO was dissolved in 16 times the mass of deionized water and ultrasonically dispersed for 30 minutes; 0.04 times the mass of GO polyacrylonitrile fiber and 2 times the mass of GO ZrO2 nanoparticles were added, and ultrasonication was continued for 2 hours (200W, 40kHz); 10 times the mass of GO silica sol was added and magnetic stirring was performed for 1 hour.

[0073] 5. Gradient transition layer slurry (intermediate layer): 20% nickel powder ethanol slurry + 10% hydrolyzate (TEOS:EtOH:H2O:ammonia mass ratio of 1.00:3.34:0.95:0.48). Stir at 25°C for 30 minutes, then centrifuge and wash (8000 rpm × 5 minutes). Add the remaining 90% hydrolyzate dropwise (0.5 mL / min), and react in a 40°C water bath for 2 hours (magnetic stirring at 200 rpm). Mix the titanium side slurry with the steel side slurry (mass ratio of 3:5), add 2wt% Ni@SiO2 microcapsules, and stir until evenly distributed.

[0074] 6. MOF-enriched layer on the titanium side: Voltage 22 kV, nozzle distance 17 cm from the titanium plate, propulsion rate 0.6 mL / min, atomization pressure 0.2 MPa. The titanium plate was placed horizontally on a heated platform (55°C), and sprayed at a constant speed (5 mm / s). Spraying was performed in three passes (with 10-minute drying intervals between each pass).

[0075] 7. Intermediate Transition Layer: Aerosol injection parameters were: 0.3 MPa pressure, 100 μm nozzle diameter, 10 mm distance from the substrate, and a slurry flow rate of 1 mL / min. Gradient Control: Dynamically proportioning with a dual syringe pump was employed. The titanium side slurry (50% MOF) was injected for the first 15 minutes, followed by a gradual switch to the transition layer slurry (35% MOF) over the next 20 minutes, creating a uniform, gradient interface.

[0076] 8. Steel side reinforcement layer: Slit coating parameters are: a 60 μm gap, a coating speed of 60 mm / s, and the steel sheet is preheated to 55°C to reduce solvent residue. The coating direction is perpendicular to the nanopillar array on the steel surface to ensure vertical alignment of the ZrO2 particles. The coating thickness is 160 μm.

[0077] 9. Hot pressing bonding and post-processing: overlap the coated titanium plate and steel sheet, pad the upper and lower with 1mm thick elastic graphite pads, and fix them in a stainless steel clamp to ensure uniform interface pressure. After the hot pressing is completed, remove the clamp and immerse it in 25℃ deionized water (the liquid level is 5cm higher than the sample), with a cooling rate of 150±20℃ / s. After quenching, the sample is ultrasonically cleaned with ethanol for 10 minutes to remove residual graphite debris on the surface, blown dry and sealed to preserve the titanium-steel composite plate. Hot pressing parameters: vacuum degree: <10-3Pa; heating program: 5℃ / min to 310℃, keep warm for 30min, continue to heat up to 460℃, keep warm for 20min; pressure control: 5MPa, a titanium-steel composite plate structure for marine engineering is obtained, such as Figure 1 and Figure 2 shown.

[0078] Comparative Example 1:

[0079] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0080] 1. Fix the titanium plate in the working chamber of the sandblasting machine, spray 100μm Al2O3 sand particles at a pressure of 0.5MPa, at a distance of 10cm, and sandblast evenly for 30s. After roughening, ultrasonically clean the titanium plate with anhydrous ethanol for 10min to remove surface dust, and blow dry for later use.

[0081] 2. A titanium plate was used as the anode, a platinum plate as the cathode, and a 0.5 M oxalic acid solution as the electrolyte. Electrolysis was performed at 20 V for 30 minutes. The electrolyte temperature was controlled at 25 ± 2°C to produce a porous TiO2 layer 5 ± 0.5 μm thick. After oxidation, the titanium plate was rinsed three times with deionized water and oven-dried at 80°C for 1 hour.

[0082] 3. Using a laser wavelength of 10-64 nm, power of 20 W, a scanning speed of 500 mm / s, and an etching pitch of 100 μm, a nanopillar array with a diameter of 50 nm and a height of 80 nm was fabricated on a steel surface. After etching, the steel sheet was ultrasonically cleaned with acetone for 15 minutes to remove surface oil.

[0083] 4. Hydrothermal Deposition of Fe₃O₄ Nanocrystals: Dissolve 0.1M FeCl₃·6H₂O and 0.3M NaAc in ethylene glycol and stir magnetically for 30 minutes until clear. Place the steel sheet vertically in a Teflon reactor. Add the solution and incubate at 180°C for 6 hours. Cool naturally, remove from heat, rinse with deionized water, and dry at 60°C for 2 hours.

[0084] 5. Titanium-side MOF-GO slurry: Weigh UiO-66-NH2, GO, and PEG-400 into an agate ball mill. Add 100 mL of anhydrous ethanol, achieving a ball-to-material ratio of 10:1 (500 g of φ5 mm zirconia balls). Run the planetary ball mill at 300 rpm for 8 hours, pausing for 5 minutes every 2 hours to prevent overheating. The mass ratio of UiO-66-NH2 to GO is 5:3.

[0085] 6. GO-ZrO2 slurry on the steel side: GO was first dissolved in 100 mL of deionized water (ultrasonicated for 30 min until uniform), ZrO2 nanoparticles were added, and ultrasonication was continued for 2 h (power 200 W, frequency 40 kHz), and 50 mL of silica sol (solid content 30%) was added. The mixture was magnetically stirred for 1 h. The mass ratio of GO and ZrO2 nanoparticles was 1:2.

[0086] 7. Gradient transition layer slurry: Mix the titanium side slurry with the steel side slurry. The mass ratio of titanium side slurry to steel side slurry is 3:5. Stir well and set aside.

[0087] 8. MOF-enriched layer on the titanium side: Voltage 20 kV, nozzle distance 15 cm from the titanium plate, propulsion rate 0.5 mL / min, atomization pressure 0.2 MPa. The titanium plate was placed horizontally on a heated platform (50°C), and sprayed at a constant speed (5 mm / s). Spraying was performed in three passes (with 10-minute drying intervals between each pass).

[0088] 9. Intermediate transition layer: air pressure 0.3 MPa, nozzle diameter 100 μm, distance from substrate 10 mm, slurry flow rate 1 mL / min; gradient control: dynamic proportioning using a dual syringe pump, injecting titanium side slurry (MOF 50%) in the first 10 minutes, and gradually switching to transition layer slurry (MOF 30%) in the next 20 minutes to form a uniform gradient interface.

[0089] 10. Steel-side reinforcement layer: Use a coating gap of 50 μm, a coating speed of 50 mm / s, and a slurry viscosity of 600 mPa·s. Preheat the steel sheet to 60°C to reduce solvent residue. Coating should be perpendicular to the nanopillar array on the steel surface to ensure vertical alignment of the ZrO2 particles.

[0090] 11. Hot Press Bonding and Post-Processing: The coated titanium plate and steel sheet were superimposed, with 1mm thick elastic graphite pads placed between them. The plates were then secured in a stainless steel fixture to ensure uniform interfacial pressure. Immediately after hot pressing, the fixture was removed and the sample immersed in 25°C deionized water (the liquid level was 5cm above the sample) at a cooling rate of 150±20°C / s. After quenching, the sample was ultrasonically cleaned in ethanol for 10 minutes to remove any residual graphite debris on the surface. The titanium-steel composite plate was then dried to obtain the desired product. Hot Press Parameters: Vacuum: <10-3 Pa; Heating Program: 5°C / min to 300°C, hold for 30 minutes, then continue heating to 450°C, hold for 20 minutes; Pressure Control: 5 MPa.

[0091] Comparative Example 2:

[0092] A method for preparing a titanium-steel composite plate structure for marine engineering comprises the following steps:

[0093] 1. Secure the titanium plate to the processing platform and set the etching parameters: 200μm spacing, 50μm depth, and a grid pattern. Laser scan the entire area to be composited. After completion, remove surface residues with compressed air. Measure 100mL of EMIC ionic liquid, add GaCl3 (1mol / L), and magnetically stir until completely dissolved. A three-electrode system (titanium plate (working electrode), platinum sheet (counter electrode), and Ag / AgCl (reference electrode)) was added to the above solution. A constant potential of -0.8V vs SCE was maintained for 10 minutes. Remove the titanium plate and ultrasonically clean it with anhydrous ethanol three times for 5 minutes each, then blow dry with nitrogen.

[0094] 2. Ultrasonic-assisted chemical plating of Ni-P alloy: dissolve NiSO4·6H2O (25 g / L) and NaH2PO2·H2O (30 g / L) in deionized water, add CH3COOH (20 mL / L), adjust the pH to 5.5 with 5 mol / LNaOH, heat the plating solution to 85℃±1℃, immerse the steel plate in suspension, turn on ultrasonic wave (200 W, frequency 40 kHz), plating for 30 min, rinse with deionized water, and dry with hot air at 100℃ for 10 min.

[0095] 3. Preparation of WS2-Ga composite intermediate layer: Add WS2 nanosheets (0.5g), Ga powder (4g), and nano-Al2O3 (0.15g) into the ball mill with a mass ratio of 1:8:0.3. Fill with Ar gas to replace the air 3 times, rotate at 300rpm, and sieve for 2h. Pass through a 300-mesh sieve to obtain a grayish-white uniform powder. Fill the mixed powder into a graphite mold, scrape the surface flat, and maintain the temperature at 150℃ (temperature control accuracy ±2℃) and pressure at 50MPa for 10min. Cool to room temperature and take out the dense flakes.

[0096] 4. Vacuum creep composite: molybdenum foil (0.2mm) → steel plate (Ni-P side facing up) → WS2-Ga composite sheet → titanium plate (Ga coating side facing down) → molybdenum foil (0.2mm), ensure that each layer is aligned and there is no foreign matter included, place the laminated assembly in the center of the press head, close the furnace, evacuate to 5×10-3Pa and start heating, heating rate: 10℃ / min to 580℃, apply pre-pressure 5MPa when the temperature reaches 400℃, keep warm at 580℃, then increase the pressure to 30MPa, maintain pressure for 60min, cool to 200℃ with the furnace, release the pressure, continue to cool to 60℃ and take out of the furnace to obtain the titanium-steel composite plate.

[0097] An axial tensile test was used to test the overall tensile strength of the composite plate along the thickness direction; a lap shear test was used to evaluate the interface shear resistance; a simulated marine environment corrosion test was used to evaluate the corrosion resistance of the composite plate in salt spray. The specimens were placed in a 3.5% NaCl solution salt spray chamber (temperature 35±2°C, pH 6.5-7.2) and sprayed continuously for 240 hours. The mass loss before and after corrosion was measured; a cyclic load peeling test was used to evaluate the fatigue resistance of the interface under dynamic load.

[0098] Table 1 Test results of titanium-steel composite plates prepared in Examples and Comparative Examples

[0099]

[0100] The results of tensile strength, shear strength, corrosion rate and interface fatigue of Examples 1-3 are all better than those of the comparative example. This is because during the vacuum hot pressing process, MOF decomposes to form amorphous ZrO2 and C, nano-boron powder reacts with the TiO2 porous layer on the titanium plate surface to form TiB2, and ZrO2 reacts with nano-boron powder to form ZrB2; TiB2 / ZrB2 is a covalent bond-metal bond mixed crystal, Ti / Zr and nano-boron powder are connected by strong covalent bonds, blocking the formation of FeTi / Fe2Ti brittle phase, and having high hardness and certain toughness. Ni particles act as a catalyst to reduce the activation energy of graphene oxide reduction and graphitization, promote the rearrangement of C atoms to form graphene, and Ni catalyzes the reduction of graphene oxide and its growth into vertical graphene arrays, blocking Cl - Diffusion path. ZrO2 nanoparticles fill the surface defects of steel, and the silica sol forms a dense SiO2 layer after solidification, which prevents H2O / Cl - Infiltration; During vacuum hot pressing, the PAN molecular chain removes gases such as HCN and NH3, carbonizes to form amorphous carbon, and then graphitizes under Ni catalysis. The graphene combines with ZrO2 nanoparticles through CO-Zr bonds, and forms chemical adsorption with Fe atoms on the surface of the steel matrix through C-Fe bonds.

[0101] The above results show and describe the basic principles and main features of this application as well as the advantages of this application.

[0102] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. A method for preparing a titanium-steel composite plate structure for marine engineering, characterized in that: The invention comprises a titanium plate, a steel sheet, and a gradient functional layer disposed between the two; the gradient functional layer is composed of a titanium-side enriched layer bonded to the titanium plate, a compositionally graded transition layer in the middle, and a steel-side reinforcement layer bonded to the steel sheet. The preparation process adopts a gradient coating process of electrostatic spraying, aerosol spraying, and slit coating, and finally vacuum hot pressing bonding to prepare a titanium-steel composite plate for marine engineering, wherein: The titanium side enrichment layer comprises a MOF loaded with nano-boron powder and SiC nanowires and graphene oxide particles dispersed therein; The composition-gradient transition layer comprises a mixed phase of a titanium side functional composite material, a steel side functional composite material and Ni@SiO2 microcapsules; The steel side reinforcement layer comprises a composite of ZrO2 nanoparticles, graphene oxide particles, polyacrylonitrile fibers and silica sol.

2. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 1, characterized in that: A nano-rough oxide layer TiO2 is provided on the titanium plate surface, and Fe3O4 nanocrystals are deposited on the steel sheet surface. The titanium side enrichment layer fills the pores of the nano-rough oxide layer TiO2 of the titanium plate, and the steel side reinforcement layer forms an anchor bond with the steel sheet surface.

3. A method for preparing a titanium-steel composite plate structure for marine engineering according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step (1): roughening and oxidizing the surface of the titanium plate to form a nano-scale rough oxide layer, and etching and Fe3O4 nanocrystal deposition on the surface of the steel sheet to form a nanocolumn array structure; Step (2): preparing a titanium side enrichment layer slurry containing a MOF-based filler, a steel side reinforcement layer slurry containing a ceramic particle reinforcement phase, and an intermediate transition layer slurry containing a gradient component; Step (3): coating a titanium side enrichment layer on the surface of the titanium plate, coating a steel side reinforcement layer on the surface of the steel sheet, and coating an intermediate transition layer with a gradient composition between the two to form a three-layer gradient functional layer; Step (4): Laminating the coated titanium plate with the steel sheet, achieving interface metallurgical bonding through vacuum hot pressing, and obtaining a titanium-steel composite plate after cooling and cleaning.

4. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: In step (1), the surface of the titanium plate is roughened by sandblasting, with Al2O3 sand particles sprayed at a pressure of 0.4-0.6 MPa, a sandblasting distance of 8-12 cm, and a sandblasting time of 25-35 s; the oxidation treatment is carried out by constant voltage electrolysis, with the titanium plate as the anode and the platinum sheet as the cathode, in a 0.4-0.6 M oxalic acid solution, at a voltage of 18-22 V for 25-35 min.

5. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: In step (1), the surface of the steel sheet is etched by laser processing, with a laser wavelength of 10-64 nm, a power of 15-25 W, a scanning speed of 400-600 mm / s, and an etching spacing of 80-120 μm; the nanocrystal deposition is carried out by a hydrothermal method, and the mass ratio of FeCl3·6H2O, NaAc, and ethylene glycol in the precursor solution is 0.8-1.2:8-10:40-42, and the temperature is kept at 170-190°C for 5-7 hours.

6. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: The preparation of the titanium side enrichment layer slurry in step (2) includes: mixing UiO-66-NH2 at a vacuum degree of 10 -2 -10 -1 Pa, immersed in nano-boron powder ethanol suspension, pressurized to 1.5-2.5MPa and maintained at pressure for 0.5-1.5h, dried and mixed with SiC nanowires, GO, PEG-400 and anhydrous ethanol and ball milled. The mass ratio of UiO-66-NH2, nano-boron powder, SiC nanowires, GO, PEG-400 and anhydrous ethanol is 7-9:0.3-0.5:1-3:4-6:9-11:75-85.

7. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: In step (3), the titanium side enrichment layer is electrostatically sprayed with a coating voltage of 18-22 kV, a nozzle distance of 13-17 cm from the substrate, a propulsion rate of 0.4-0.6 mL / min, and sprayed multiple times on a 45-55 ° C heating platform. The coating thickness is 40-60 μm.

8. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: In step (3), the intermediate transition layer is coated by aerosol spraying. The slurry components are controlled by dynamic proportioning of dual pumps. In the first 10-15 minutes, the titanium side slurry containing 50%-60% MOF-based fillers is injected. In the next 20-25 minutes, the transition slurry containing 25%-35% MOF-based fillers is gradually switched to form a gradient interface layer with a thickness of 100±10μm.

9. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: In step (3), the steel side reinforcement layer adopts a slit coating process with a coating gap of 40-60 μm and a coating speed of 40-60 mm / s. The steel sheet is preheated to 55-65 °C. The coating direction is perpendicular to the nanocolumn array so that the ZrO2 particles are oriented and the coating thickness is 140-160 μm.

10. The method for preparing a titanium-steel composite plate structure for marine engineering according to claim 3, characterized in that: The vacuum hot pressing conditions in step (4) are: vacuum degree <10⁻³Pa, heating rate 4-6°C / min, keeping at 290-310°C for 25-35min, keeping at 440-460°C for 15-25min, and pressure 4-6MPa.

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