High-tungsten corrosion-resistant titanium alloy bipolar plate and preparation method thereof

Abstract

The application belongs to the technical field of metal bipolar plate materials for hydrogen production by water electrolysis, and particularly relates to a high-tungsten corrosion-resistant titanium alloy bipolar plate and a preparation method thereof. Sponge titanium powder, tungsten powder, aluminum powder, niobium powder, molybdenum powder, chromium powder, a tungsten fluoride acid root bridged yttrium titanate complex and tantalum doped cerium oxide coated tungsten carbide particles are mixed, cold isostatic pressing is performed, and then vacuum hot pressing sintering, hot rolling, solid solution treatment and aging treatment are performed to obtain a plate material, the plate material is reprocessed into a bipolar plate and surface treatment is performed. The bipolar plate obtained by the application has uniform structure, stable tungsten element distribution and dense surface passivation film, and has corrosion resistance, electrical conductivity and service stability, and is suitable for a water electrolysis hydrogen production device.

Description

Technical Field

[0001] This invention belongs to the technical field of metal bipolar plate materials for hydrogen production by water electrolysis, specifically relating to a high-tungsten corrosion-resistant titanium alloy bipolar plate and its preparation method. Background Technology

[0002] Proton exchange membrane electrolysis for hydrogen production offers advantages such as rapid start-up and shutdown, high hydrogen purity, and suitability for coupling with renewable energy sources, making it a crucial development direction in the green hydrogen production field. Bipolar plates, as key structural components in water electrolysis stacks, must fulfill multiple functions, including conductivity, support, gas-liquid separation, transfer of reaction media, and maintenance of flow field stability. Their performance directly impacts stack efficiency, service life, and manufacturing costs. Under acidic, high-humidity, oxygen-rich, and high-potential operating environments, bipolar plate surfaces are prone to passivation film damage, localized corrosion, increased contact resistance, and decreased interfacial stability. Therefore, high requirements are placed on the corrosion resistance, conductivity, mechanical stability, and processing adaptability of the materials.

[0003] Among existing metal bipolar plate materials, stainless steel has cost advantages and ease of processing, but its corrosion resistance is insufficient in strong acid and high-potential environments, and unstable corrosion products easily form on its surface, leading to increased interfacial contact resistance. Titanium and titanium alloys have good corrosion resistance and low density, making them suitable for use in water electrolysis bipolar plates. However, the titanium oxide film formed on its surface may experience insufficient density, local defect propagation, and reduced conductivity during long-term operation. Simply relying on traditional titanium alloy element control makes it difficult to simultaneously meet the requirements of corrosion resistance, conductivity, microstructure uniformity, and low-cost preparation. Especially under high current density operating conditions, micro-corrosion and interfacial resistance accumulation on the bipolar plate surface will gradually amplify, affecting the long-term stable operation of the fuel cell stack.

[0004] Tungsten possesses a high melting point, excellent acid corrosion resistance, and strong stabilizing properties. Introducing it into a titanium alloy system can enhance the corrosion resistance and structural stability of bipolar plates in harsh media. However, the density and diffusion behavior differences between tungsten and titanium can lead to problems such as elemental segregation, uneven microstructure, and difficulties in sintering and densification during preparation. Existing surface coatings or simple alloying methods also suffer from insufficient coating adhesion, susceptibility to cracking and peeling after long-term service, uneven distribution of conductive phases, and high processing costs. Therefore, it is necessary to develop a high-tungsten corrosion-resistant titanium alloy bipolar plate and its preparation method. Through synergistic modification of alloy powder, densification molding, and heat treatment control, the tungsten distribution can be made more stable, improving the quality of the surface passivation film, reducing the risk of corrosion failure, and balancing conductivity, processability, and feasibility for large-scale preparation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a high-tungsten corrosion-resistant titanium alloy bipolar plate, comprising the following steps:

[0006] S1. By weight, mix 60.0-75.0 parts of sponge titanium powder, 12.0-20.0 parts of tungsten powder, 2.0-4.0 parts of aluminum powder, 1.5-3.0 parts of niobium powder, 1.0-2.5 parts of molybdenum powder, and 0.5-1.5 parts of chromium powder to obtain a basic alloy powder; add 1.5-3.5 parts of fluoride tungstate-bridged yttrium titanate complex and 2.0-4.0 parts of tantalum-doped cerium oxide-coated tungsten carbide particles to the basic alloy powder, and continue mixing to obtain a composite alloy powder; subject the composite alloy powder to cold isostatic pressing to obtain a billet;

[0007] S2. Place the billet in a hot pressing sintering mold and sinter it under vacuum to obtain a sintered billet; hot roll the sintered billet and cool it; then perform a solution treatment and cool it; perform an aging treatment and cool it to obtain a plate; process the plate into a bipolar plate, and polish, clean and dry the surface.

[0008] In this invention, the preparation process of the high-tungsten corrosion-resistant titanium alloy bipolar plate mainly includes stages such as powder mixing, cold pressing, diffusion sintering, hot working, and heat treatment stabilization. Sponge titanium powder serves as the titanium matrix powder. Tungsten powder, aluminum powder, niobium powder, molybdenum powder, and chromium powder are mechanically mixed with the sponge titanium powder in a specific ratio and distributed between the sponge titanium powder particles to obtain the basic alloy powder. Further addition and mixing of tungstate-bridged yttrium titanate complex and tantalum-doped cerium oxide-coated tungsten carbide particles result in fine, dispersed particles adhering to the surface of the basic alloy powder particles and the interparticle spaces, thus obtaining the composite alloy powder. During cold isostatic pressing, the composite alloy powder undergoes particle rearrangement and plastic compaction under uniform high pressure, compressing the interparticle voids and forming a billet with a certain green strength and a continuous contact interface. During hot-pressing sintering of the billet under a vacuum atmosphere, the vacuum environment inhibits powder oxidation and nitriding, while the applied pressure increases the contact area between particles and opens atomic-level diffusion channels. The sponge titanium powder undergoes plastic deformation and diffusion bonding. Tungsten, aluminum, niobium, molybdenum, and chromium powders interdiffusion with the titanium matrix to form a continuous alloy solid solution and achieve alloying. Residual porosity gradually shrinks and disappears under the combined action of pressure and diffusion. Fluorotungstate-bridged yttrium titanate complexes are distributed at the grain boundaries of the titanium matrix and around the tungsten particles. Some fluorine volatilizes at high temperatures, while the remaining tungsten, titanium, yttrium, and oxygen form dispersed composite oxide particles that pin the grain boundaries to inhibit grain growth and promote interfacial metallurgical bonding between the tungsten particles and the titanium matrix. Under vacuum protection, the tungsten carbide main phase and the outer tantalum-doped cerium oxide phase of the tungsten carbide particles are retained and dispersed at the grain boundaries and within the titanium matrix, participating in the microstructure as corrosion-resistant and conductive phases. After hot rolling, the residual pores in the sintered billet are further compacted and densified. Coarse grains undergo plastic elongation and dynamic recrystallization along the rolling direction, resulting in a finer and more uniform microstructure. Solution treatment causes the supersaturated elements to redissolve and distribute more evenly within the titanium matrix. During aging treatment, the supersaturated dissolved elements desolve and precipitate a dispersed second phase. This dispersed second phase, together with the original modified compound particles, constitutes a strengthening and corrosion-resistant phase. The resulting sheet is processed into a bipolar plate shape. The surface is ground to remove the oxide layer and rough defect layer, cleaned to remove grinding residue, and dried to remove surface moisture, yielding a high-tungsten corrosion-resistant titanium alloy bipolar plate.

[0009] According to a preferred embodiment of the present invention, in step S1, the pressure of the cold isostatic pressing is 200-250 MPa.

[0010] According to a preferred embodiment of the present invention, in step S2, the hot pressing sintering step includes: under a vacuum degree of 1×10 -3 -5×10 -3Under Pa, the temperature is raised to 1180-1220℃, and a pressure of 30-40MPa is applied simultaneously for heat and pressure holding; the hot rolling step includes: heating the sintered billet to 950-1000℃ and holding it at that temperature; the solution treatment step includes: holding it at 800-850℃; the aging treatment step includes: holding it at 500-550℃.

[0011] According to a preferred embodiment of the present invention, the method for preparing the fluorinated tungstate-bridged yttrium titanate complex includes:

[0012] A1. By weight, mix 6.5-13.5 parts of sodium tungstate dihydrate and 80.0-100.0 parts of deionized water, add 1.4-3.0 parts of ammonium fluoride, stir, and adjust the pH to 3.5-4.5 with acetic acid to obtain an acidified fluorotungstate solution; dissolve 3.8-7.8 parts of yttrium nitrate hexahydrate in 24.0-40.0 parts of anhydrous ethanol, add the acidified fluorotungstate solution, and stir at 40-50℃ to obtain a tungsten-fluorine-yttrium composite solution; mix 3.4-6.8 parts of tetrabutyl titanate and 16.0-24.0 parts of anhydrous ethanol, add to the tungsten-fluorine-yttrium composite solution, and stir at 50-60℃ to obtain a tungsten-fluorine-titanium-yttrium composite sol;

[0013] A2. The tungsten-fluorine-titanium-yttrium composite sol is subjected to a hydrothermal reaction, cooled, separated, washed, and dried to obtain precursor powder; under a nitrogen protective atmosphere, the precursor powder is heated to 350-400℃ and held at that temperature, then cooled, pulverized, and sieved.

[0014] In this invention, the preparation process of the fluorinated tungstate-bridged yttrium titanate complex mainly includes four stages: tungstate acidification and fluorine coordination, yttrium ion complexation, controlled hydrolysis and condensation of the titanium source, and precursor inorganic treatment. Sodium tungstate dihydrate dissolves in deionized water and dissociates to form tungstate anions. Ammonium fluoride is added and dissociates to release fluoride ions. The fluoride ions replace some of the coordinated oxygen in the tungstate and form bonds with the tungsten center, forming a soluble fluorinated tungstate coordination species in the solution. After adjusting the acidity of the system with acetic acid, the acidity is controlled within a range that inhibits paratungstate precipitation and is suitable for slow hydrolysis of the titanium source. Yttrium nitrate hexahydrate is first dissolved in anhydrous ethanol to obtain a clear yttrium ion alcoholic solution. After adding the acidified fluorinated tungstate solution, the yttrium ions complex with the bridging oxygen and terminal oxygen sites in the fluorinated tungstate coordination species, and yttrium is bound to the outer coordination sites of the fluorinated tungstate framework, forming a homogeneous tungsten-fluorine-yttrium composite solution. Tetrabutyl titanate is first premixed with anhydrous ethanol to reduce its reaction rate with water. After adding a tungsten-fluorine-yttrium composite solution, under the chelating protection of acetic acid, the butoxy groups of tetrabutyl titanate are gradually replaced by water molecules to form hydroxyl groups, generating titanium species containing titanium hydroxyl groups. These titanium species undergo dehydration condensation with the tungsten-fluorine-yttrium coordinating species, forming bridging structures between titanium, oxygen, and tungsten, and between titanium, oxygen, and yttrium. These structures gradually assemble into a sol framework involving tungsten, fluorine, titanium, and yttrium, yielding a tungsten-fluorine-titanium-yttrium composite sol. Following a hydrothermal reaction, the sol framework further condenses and rearranges, expelling pore water and forming a homogeneous amorphous precursor. Cooling, separation, washing, and drying processes remove free salts, solvents, and unbound organic residues, yielding the precursor powder. When the precursor powder is heated and held at a temperature under a nitrogen protective atmosphere, the residual butoxy group and acetate group are removed by thermal decomposition and leave the system as volatile components. Fluorine element is retained in the inorganic framework in the form of a bridging position. A stable composite fluoride oxide framework is formed between tungsten, fluorine, titanium and yttrium to obtain the tungstate fluoride-bridged yttrium titanate complex.

[0015] According to a preferred embodiment of the present invention, in step A1, the stirring time at 40-50°C is 1-2 hours; and the stirring time at 50-60°C is 4-6 hours.

[0016] According to a preferred embodiment of the present invention, in step A2, the temperature of the hydrothermal reaction is 140-160°C, the time of the hydrothermal reaction is 12-16h; the drying temperature is 60-80°C; and the holding time at 350-400°C is 2-3h.

[0017] According to a preferred embodiment of the present invention, the method for preparing the tantalum-doped cerium oxide-coated tungsten carbide particles includes:

[0018] B1. By weight, mix 30.0-62.0 parts ammonium paratungstate, 10.0-15.0 parts carbon black and 80.0-100.0 parts deionized water, disperse by ultrasonication, and dry to obtain tungsten carbide precursor powder; under a mixed atmosphere of hydrogen and argon, heat the tungsten carbide precursor powder to 950-1000℃ and hold for a period of time, then cool to obtain tungsten carbide particles; disperse 0.5-1.0 parts of tungsten carbide particles in a mixture of 50.0-75.0 parts deionized water and 40.0-60.0 parts anhydrous ethanol, add 1.0-1.5 parts poloxamer 407, disperse by ultrasonication, add 6.5-11.0 parts cerium nitrate hexahydrate and an anhydrous ethanol solution containing 0.5-0.9 parts tantalum pentachloride, stir to obtain tungsten carbide cerium tantalum composite dispersion;

[0019] B2. Add ammonia dropwise to the tungsten carbide-cerium-tantalum composite dispersion to adjust the pH to 9.5-10.5, and stir at 60-70℃ to obtain a tantalum-cerium deposited tungsten carbide composite. Perform a hydrothermal reaction on the tantalum-cerium deposited tungsten carbide composite, cool, separate, wash, and dry to obtain a dry powder. In an air atmosphere, heat the dry powder to 400-450℃ and keep it at that temperature, then cool, pulverize, and sieve.

[0020] In this invention, the preparation process of tantalum-doped cerium oxide-coated tungsten carbide particles mainly includes four stages: tungsten-carbon precursor formation, reduction and carbonization reaction, cerium-tantalum co-precipitation coating, and outer layer oxidation and solidification. Ammonium paratungstate is partially dissolved in deionized water, with the remainder suspended in the form of fine crystals. After carbon black is added, it is ultrasonically dispersed to achieve close contact with the ammonium paratungstate particles and dissolved species. During the drying process, moisture is removed, and ammonium paratungstate precipitates on the carbon black surface and adheres uniformly, forming a tungsten-carbon precursor powder with close contact between the tungsten source and the carbon source. When the tungsten-carbon precursor powder is heated and held at a temperature under a mixed atmosphere of hydrogen and argon, ammonium paratungstate first undergoes deammoniation and dehydration to decompose into tungsten oxide. Subsequently, hydrogen gradually reduces the tungsten oxide to lower valence tungsten oxides until metallic tungsten. Simultaneously, carbon black, as a carbon source, diffuses to the surface of metallic tungsten and undergoes a carbonization reaction, gradually converting metallic tungsten into tungsten carbide. Argon provides inert protection and dilutes the partial pressure of water vapor, a reduction byproduct, allowing the reduction and carbonization reactions to proceed in the forward direction, ultimately yielding tungsten carbide particles. After the prepared tungsten carbide particles are dispersed in a mixture of deionized water and anhydrous ethanol, poloxamer 407 is ultrasonically dispersed and adsorbed onto the surface of the tungsten carbide particles. Its polyether segments provide steric hindrance, inhibiting the aggregation of tungsten carbide particles. Cerium nitrate hexahydrate dissociates and releases trivalent cerium ions as a cerium source. In anhydrous ethanol solution containing tantalum pentachloride, tantalum pentachloride reacts with anhydrous ethanol beforehand to generate a tantalum ethoxy intermediate and release hydrogen chloride, effectively avoiding the violent hydrolysis caused by direct contact between tantalum pentachloride and water. After ammonia is added dropwise to the tungsten carbide-cerium-tantalum composite dispersion, the system becomes alkaline. Trivalent cerium ions combine with hydroxide ions to generate cerium hydroxide. The tantalum ethoxy intermediate undergoes controlled hydrolysis in the alkaline aqueous phase to generate hydrated tantalum hydroxide. Both are co-precipitated and deposited on the surface of the poloxamer 407-modified tungsten carbide particles, forming a tantalum-cerium deposited tungsten carbide composite. After hydrothermal reaction, the tantalum-cerium deposited tungsten carbide composite undergoes further densification of the surface deposit layer, forming a continuous bond with the surface of the tungsten carbide particles. Cooling, separation, washing, and drying yield a dry powder. The dry powder is then heated and held at a temperature in air. Cerium hydroxide dehydrates and is oxidized by oxygen in the air to cerium oxide with a fluorite structure. Hydrated tantalum hydroxide dehydrates to form tantalum oxide. Tantalum replaces cerium sites in the cerium oxide fluorite lattice as a high-valence cation, accompanied by the generation of charge-compensating oxygen vacancies. Poloxamer 407 is oxidized and decomposed within this temperature range, leaving mesoporous channels in the outer layer, resulting in tantalum-doped cerium oxide-coated tungsten carbide particles.

[0021] According to a preferred embodiment of the present invention, in step B1, the time for holding the temperature at 950-1000°C is 2-3 hours.

[0022] According to a preferred embodiment of the present invention, in step B2, the stirring time at 60-70°C is 4-5 hours; the temperature of the hydrothermal reaction is 160-180°C, and the hydrothermal reaction time is 8-10 hours; the holding time at 400-450°C is 3-4 hours.

[0023] The present invention also provides a high-tungsten corrosion-resistant titanium alloy bipolar plate prepared according to the preparation method of the high-tungsten corrosion-resistant titanium alloy bipolar plate.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention utilizes a combination of sponge titanium powder, tungsten powder, aluminum powder, niobium powder, molybdenum powder, and chromium powder, and processes them through cold isostatic pressing, vacuum hot pressing sintering, hot rolling, solution treatment, and aging treatment to obtain a high-tungsten corrosion-resistant titanium alloy bipolar plate with a relatively dense alloy structure. The vacuum atmosphere can reduce powder oxidation during sintering, hot pressing sintering can promote diffusion bonding between powder particles, hot rolling can further compress residual pores, and solution treatment and aging treatment can improve the distribution of alloying elements, thereby reducing the adverse effects of uneven structure on corrosion resistance.

[0026] (2) The fluorinated tungstate-bridged yttrium titanate complex is dispersed in the composite alloy powder and participates in the formation of powder interface and grain boundary structure during hot pressing and sintering, forming a dispersed inorganic phase containing tungsten, titanium, and yttrium. This dispersed inorganic phase can limit abnormal grain growth, improve the interfacial bonding between tungsten powder and titanium matrix, reduce structural defects caused by local enrichment of tungsten elements, make the surface passivation structure of the high-tungsten corrosion-resistant titanium alloy bipolar plate more continuous, and reduce the risk of local corrosion and surface peeling.

[0027] (3) Tantalum-doped cerium oxide-coated tungsten carbide particles are dispersed near the grain boundaries and surface of the titanium matrix. The tungsten carbide particles provide a stable conductive phase, and the tantalum-doped cerium oxide structure improves the surface corrosion resistance. The tantalum-doped cerium oxide-coated tungsten carbide particles and the yttrium titanate complex bridged by tungstate fluoride work together to give the high-tungsten corrosion-resistant titanium alloy bipolar plate good corrosion resistance, conductivity and structural stability in acidic, high-humidity and high-potential environments, making it suitable for bipolar plate components in water electrolysis hydrogen production equipment. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. The drawings are only used to illustrate the implementation methods and are not intended to limit the present invention.

[0029] Figure 1 (1a-1e) are surface morphology images of the high tungsten corrosion-resistant titanium alloy bipolar plate prepared in Example 1 before corrosion testing.

[0030] Figure 2 (2a-2g) are surface morphology images of the high tungsten corrosion-resistant titanium alloy bipolar plate prepared in Example 1 after corrosion testing.

[0031] Figure 3The image shows the metallographic structure of the high-tungsten corrosion-resistant titanium alloy bipolar plate of Example 1. Figure 3 a, Figure 3 b、 Figure 3 c represents metallographic diagrams at different scales.

[0032] Figure 4 The image shows the XRD pattern of the fluorinated tungstate-bridged yttrium titanate complex prepared in Example 1.

[0033] Figure 5 The image shows the XRD pattern of tantalum-doped cerium oxide-coated tungsten carbide particles prepared in Example 1. Detailed Implementation

[0034] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0035] Example 1

[0036] This embodiment provides a method for preparing a high-tungsten corrosion-resistant titanium alloy bipolar plate, the steps of which include:

[0037] S1. Add 67.5g of sponge titanium powder, 16.0g of tungsten powder, 3.0g of aluminum powder, 2.25g of niobium powder, 1.75g ​​of molybdenum powder, and 1.0g of chromium powder to a mixing container and mix for 60 minutes to obtain a basic alloy powder. Add 2.5g of tungstate fluoride-bridged yttrium titanate complex and 3.0g of tantalum-doped cerium oxide-coated tungsten carbide particles to the basic alloy powder and continue mixing for 60 minutes to obtain a composite alloy powder. Load the composite alloy powder into a cold isostatic pressing mold and perform cold isostatic pressing at 225MPa for 8 minutes to obtain a billet.

[0038] S2. Place the billet in a hot-pressing sintering mold, under a vacuum of 3×10⁻⁶. -3Under a vacuum atmosphere of Pa, the temperature was raised to 1200°C, and a pressure of 35 MPa was applied simultaneously. The temperature and pressure were held for 105 min to obtain a sintered billet. The sintered billet was then heated to 975°C and held for 35 min before hot rolling, with a total deformation of 65%, followed by cooling to 25°C. Subsequently, a solution treatment was performed at 825°C for 1.25 h, followed by cooling to 25°C. Finally, an aging treatment was performed at 525°C for 5 h, followed by cooling to 25°C to obtain a sheet metal. The sheet metal was then processed into bipolar plates using a precision stamping process. The pressure was 150 MPa, the mold gap was 0.02 mm, the flow field structure was a serpentine channel with a channel width of 1.0 mm, a depth of 0.4 mm, a ridge width of 1.0 mm, and an overall thickness of 0.15 mm for the bipolar plate. The surface of the bipolar plate was successively polished, cleaned, and dried. Polishing was performed until there was no visible oxide scale or obvious scratches on the surface. Cleaning was performed by ultrasonic cleaning with anhydrous ethanol for 15 min, followed by rinsing with deionized water. The drying temperature was 60°C and the drying time was 2 h to obtain a high-tungsten corrosion-resistant titanium alloy bipolar plate.

[0039] Preparation steps of fluorinated tungstate-bridged yttrium titanate complexes:

[0040] A1. Add 10.0g of sodium tungstate dihydrate to 90.0g of deionized water, stir at 300r / min for 20min at 25°C to disperse and dissolve the sodium tungstate dihydrate, add 2.2g of ammonium fluoride, and continue stirring at 300r / min for 35min. Adjust the pH to 4.0 with acetic acid to obtain an acidified fluorotungstate solution; add 5.8g of yttrium hexahydrate to 32.0g of anhydrous ethanol, stir at 300r / min for 15min at 25°C to obtain an ethanol solution of yttrium hexahydrate; add yttrium hexahydrate... An ethanol solution of the compound was added to an acidified fluorotungstate solution over a period of 20 min, followed by stirring at 300 rpm for 1.5 h at 45°C to obtain a tungsten-fluorine-yttrium composite solution. 5.1 g of tetrabutyl titanate was added to 20.0 g of anhydrous ethanol, and stirred at 300 rpm for 10 min at 25°C to obtain a tetrabutyl titanate ethanol solution. This tetrabutyl titanate ethanol solution was then added to the tungsten-fluorine-yttrium composite solution over a period of 30 min, followed by stirring at 300 rpm for 5 h at 55°C to obtain a tungsten-fluorine-titanium-yttrium composite sol.

[0041] A2. The tungsten-fluorine-titanium-yttrium composite sol was transferred into a hydrothermal reaction vessel with a filling rate of 70%. The hydrothermal reaction was carried out at 150°C for 14 hours. After the reaction was completed, the mixture was cooled to 25°C and separated at 8000 r / min for 10 minutes. The solid product was collected, washed three times with 30.0 g of deionized water, and dried at 70°C for 10 hours to obtain the precursor powder. The precursor powder was placed in a tube furnace, purged with nitrogen three times, and then kept under a nitrogen protective atmosphere. The temperature was raised to 375°C and held for 2.5 hours. The mixture was then cooled to 25°C, pulverized for 30 minutes, and passed through a 75 μm sieve to obtain the fluorinated tungstate-bridged yttrium titanate complex.

[0042] Preparation steps of tantalum-doped cerium oxide-coated tungsten carbide particles:

[0043] B1. Mix 46.0g ammonium paratungstate, 12.5g carbon black, and 90.0g deionized water, and ultrasonically disperse at 25°C, 40kHz, and 300W for 40min. Dry at 80°C for 12h, pulverize, and pass through a 75μm sieve to obtain tungsten carbide precursor powder. Place the tungsten carbide precursor powder in a tube furnace, purge with argon three times, and then introduce a mixed atmosphere of hydrogen and argon, with a hydrogen component of 12%. Heat the tungsten carbide precursor powder to 975°C and hold for 2.5h, then cool to 25°C under argon protection to obtain tungsten carbide particles. Add 0.75g of tungsten carbide particles to a mixture of 62.5g deionized water and 50.0g anhydrous ethanol, and heat at 2... The mixture was ultrasonically dispersed at 40 kHz and 300 W for 30 min at 5°C. 1.25 g of poloxamer 407 was added, and the mixture was ultrasonically dispersed again at 40 kHz and 300 W for 30 min. 8.75 g of cerium nitrate hexahydrate was added, and the mixture was stirred at 300 r / min for 30 min. 0.7 g of tantalum pentachloride was added to 8.0 g of anhydrous ethanol, and the mixture was stirred at 300 r / min for 20 min at 25°C to obtain an anhydrous ethanol solution containing 0.7 g of tantalum pentachloride. The anhydrous ethanol solution containing 0.7 g of tantalum pentachloride was added to the above system over a period of 15 min, followed by stirring at 300 r / min for 1 h to obtain a tungsten carbide-cerium-tantalum composite dispersion.

[0044] B2. Ammonia water with a mass fraction of 25% was added dropwise to the tungsten carbide-cerium-tantalum composite dispersion to adjust the pH to 10.0. The mixture was stirred at 300 r / min for 4.5 h at 65°C to obtain a tantalum-cerium deposited tungsten carbide composite. The tantalum-cerium deposited tungsten carbide composite was transferred to a hydrothermal reaction vessel with a filling rate of 70%. The reaction was carried out at 170°C for 9 h. After the reaction was completed, the mixture was cooled to 25°C and separated at 8000 r / min for 10 min. The solid product was collected, washed three times with 30.0 g of deionized water, and dried at 80°C for 12 h to obtain a dry powder. The dry powder was placed in a muffle furnace and heated to 425°C in an air atmosphere for 3.5 h. After cooling to 25°C, the powder was pulverized for 30 min and passed through a 75 μm sieve to obtain tantalum-doped cerium oxide-coated tungsten carbide particles.

[0045] Depend on Figure 4 It can be seen that the sample did not show any sharp Bragg diffraction peaks throughout the entire 2θ scan range, only two distinctly broadened peaks at approximately 27° and 52°, accompanied by a weak bulge near a low angle of approximately 12°. Overall, it exhibits typical amorphous short-range ordered characteristics, which is consistent with the process design of this invention, in which an amorphous precursor is obtained hydrothermally, and then only inorganically treated at 350-400°C under a nitrogen atmosphere without reaching the crystallization temperature of the quaternary composite fluorine oxide. This indicates that organic residues have been effectively removed within this temperature window and the system has not yet undergone phase separation. The main peak is located near 27°, corresponding to the short-range order of the tungsten-oxygen first coordination shell. The distance (d≈3.3Å) and the secondary peak at 52° are attributed to the scattering contribution of the next nearest neighbor coordination shell. The coexistence of the two peaks indicates that the four elements, tungsten, fluorine, titanium, and yttrium, are uniformly mixed at the atomic scale and construct a stable short-range ordered framework through bridging oxygen and fluorine. Meanwhile, the absence of characteristic diffraction peaks of WO3, Y2O3, TiO2, and Y2Ti2O7 in the spectrum further confirms that fluorine effectively suppresses the independent crystallization and phase separation of each component in a bridging manner. The four elements are assembled together in a synergistic coordination manner to form an amorphous composite fluoride oxide framework. In summary, this invention successfully prepared a tungstate fluoride-bridged yttrium titanate complex.

[0046] Depend on Figure 5It can be seen that the present invention successfully prepared tantalum-doped cerium oxide-coated tungsten carbide particles. In the spectrum, a set of sharp and high-intensity diffraction peaks appeared at approximately 31.5°, 35.6°, 48.3°, 64.0°, 65.8°, 73.1°, 75.5°, 77.1° and 84.1° at 2θ, which correspond to the (001), (100), (101), (110), (002), (111), (200), (102) and (201) crystal planes of hexagonal tungsten carbide (JCPDS25-1047), respectively. The sharp peaks indicate that the reduction carbonization stage was completely reacted in a hydrogen-argon mixed atmosphere at 950-1000℃, generating a well-crystallized WC core, and no W2C, metallic W or free carbon impurity phase diffraction peaks were detected, indicating that the ratio of tungsten source to carbon source was matched and the reduction carbonization process was thorough. Meanwhile, a set of significantly broadened diffraction peaks was observed at approximately 28.7°, 33.3°, 47.7°, 56.5°, 59.3°, 69.6°, 76.9°, and 79.3° at 2θ, which completely correspond to the (111), (200), (220), (311), (222), (400), (331), and (420) crystal planes of the fluorite structure CeO2 (JCPDS34-0394). The peak broadening is attributed to the nanoscale coating layer formed by air calcination at 400-450℃ and the mesoporous structure left by the decomposition of poloxamer 407. Compared to the pure CeO2 standard card, each CeO2 peak shifts slightly to higher angles by about 0.15-0.20°, indicating that the smaller Ta ionic radius... 5+ It has successfully replaced Ce 4+ The presence of tantalum in the fluorite lattice and the resulting lattice contraction, along with the absence of independent Ta₂O₅ diffraction peaks in the spectrum, indicates that tantalum is uniformly embedded in the CeO₂ lattice in a solid solution doping form rather than precipitating as an independent second phase. Combined with the diffraction characteristics of the coexistence of WC and Ta-doped CeO₂ phases with distinct features, this invention fully demonstrates the successful preparation of a core-shell composite particle with WC as the core and Ta-doped CeO₂ as the shell.

[0047] Example 2

[0048] The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing a high-tungsten corrosion-resistant titanium alloy bipolar plate, the steps of which include:

[0049] S1. Mix 60.0g of sponge titanium powder, 12.0g of tungsten powder, 2.0g of aluminum powder, 1.5g of niobium powder, 1.0g of molybdenum powder, and 0.5g of chromium powder until there is no obvious local enrichment to obtain a basic alloy powder; add 1.5g of fluoride tungstate-bridged yttrium titanate complex and 2.0g of tantalum-doped cerium oxide-coated tungsten carbide particles to the basic alloy powder, and continue mixing until the powder is uniform to obtain a composite alloy powder; load the composite alloy powder into a cold isostatic pressing mold and perform cold isostatic pressing at 200MPa to obtain a billet;

[0050] S2. Place the billet in a hot-pressing sintering mold, under a vacuum of 1×10⁻⁶. -3 Under a vacuum atmosphere of Pa, the temperature is raised to 1180°C, and a pressure of 30 MPa is applied simultaneously. The temperature and pressure are maintained to obtain a sintered billet. The sintered billet is heated to 950°C and held for 4 hours before hot rolling. The total deformation during hot rolling is 60%, and then it is cooled. Subsequently, a solution treatment is performed at 800°C, followed by cooling. Then, an aging treatment is performed at 500°C for 4 hours, followed by cooling to obtain a plate. The plate is processed into a bipolar plate, and the surface of the bipolar plate is polished, cleaned, and dried to obtain a high-tungsten corrosion-resistant titanium alloy bipolar plate.

[0051] Preparation steps of fluorinated tungstate-bridged yttrium titanate complexes:

[0052] A1. Add 6.5g of sodium tungstate dihydrate to 80.0g of deionized water and stir until the sodium tungstate dihydrate is dispersed and dissolved. Add 1.4g of ammonium fluoride and continue stirring until the system is homogeneous. Adjust the pH to 3.5 with acetic acid to obtain an acidified fluorotungstate solution. Add 3.8g of yttrium hexahydrate to 24.0g of anhydrous ethanol and stir until dissolved to obtain an yttrium hexahydrate ethanol solution. Add the yttrium hexahydrate ethanol solution to the acidified fluorotungstate solution and stir at 40°C for 1h to obtain a tungsten-fluorine-yttrium composite solution. Add 3.4g of tetrabutyl titanate to 16.0g of anhydrous ethanol and stir until homogeneous to obtain a tetrabutyl titanate ethanol solution. Add the tetrabutyl titanate ethanol solution to the tungsten-fluorine-yttrium composite solution and stir at 50°C for 4h to obtain a tungsten-fluorine-titanium-yttrium composite sol.

[0053] A2. The tungsten-fluorine-titanium-yttrium composite sol was transferred into a hydrothermal reaction vessel and hydrothermally reacted at 140°C for 12 hours. After the reaction was completed, it was cooled to room temperature, the solid product was separated, washed with deionized water, and then dried at 60°C to obtain the precursor powder. The precursor powder was placed in a nitrogen protective atmosphere, heated to 350°C and held for 2 hours, cooled to room temperature, pulverized, and sieved to obtain the fluorinated tungstate-bridged yttrium titanate complex.

[0054] Preparation steps of tantalum-doped cerium oxide-coated tungsten carbide particles:

[0055] B1. Mix 30.0g ammonium paratungstate, 10.0g carbon black, and 80.0g deionized water, and ultrasonically disperse until the ammonium paratungstate and carbon black are uniformly dispersed. Dry to obtain tungsten carbide precursor powder. Place the tungsten carbide precursor powder in a mixed atmosphere of hydrogen and argon, heat to 950°C and hold for 2 hours, then cool to room temperature to obtain tungsten carbide particles. Add 0.5g of tungsten carbide particles to a mixture of 50.0g deionized water and 40.0g anhydrous ethanol, and ultrasonically disperse until the tungsten carbide particles show no obvious agglomeration. Add 1.0g poloxamer 407 and continue ultrasonic dispersion. Add 6.5g cerium nitrate hexahydrate and stir until dissolved and uniformly dispersed. Dissolve 0.5g tantalum pentachloride in anhydrous ethanol to obtain an anhydrous ethanol solution containing 0.5g tantalum pentachloride. Add the anhydrous ethanol solution containing 0.5g tantalum pentachloride to the above system and stir until uniform to obtain a tungsten carbide-cerium-tantalum composite dispersion.

[0056] B2. Add ammonia dropwise to the tungsten carbide-cerium-tantalum composite dispersion to adjust the pH to 9.5, and stir at 60°C for 4 hours to obtain a tantalum-cerium deposited tungsten carbide composite. Transfer the tantalum-cerium deposited tungsten carbide composite to a hydrothermal reaction vessel and react hydrothermally at 160°C for 8 hours. After the reaction is completed, cool to room temperature, separate the solid product, wash and dry it to obtain a dry powder. Place the dry powder in an air atmosphere, heat it to 400°C and keep it at that temperature for 3 hours, cool it to room temperature, pulverize and sieve it to obtain tantalum-doped cerium oxide-coated tungsten carbide particles.

[0057] Example 3

[0058] The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing a high-tungsten corrosion-resistant titanium alloy bipolar plate, the steps of which include:

[0059] S1. Mix 75.0g of sponge titanium powder, 20.0g of tungsten powder, 4.0g of aluminum powder, 3.0g of niobium powder, 2.5g of molybdenum powder, and 1.5g of chromium powder until there is no obvious local enrichment to obtain a basic alloy powder; add 3.5g of tungstate fluoride-bridged yttrium titanate complex and 4.0g of tantalum-doped cerium oxide-coated tungsten carbide particles to the basic alloy powder, and continue mixing until the powder is uniform to obtain a composite alloy powder; load the composite alloy powder into a cold isostatic pressing mold and perform cold isostatic pressing at 250MPa to obtain a billet;

[0060] S2. Place the billet in a hot-pressing sintering mold, under a vacuum of 5×10⁻⁶. -3Under a vacuum atmosphere of Pa, the temperature is raised to 1220°C, and a pressure of 40 MPa is applied simultaneously. The temperature and pressure are maintained to obtain a sintered billet. The sintered billet is heated to 1000°C and held for 6 hours before hot rolling. The total deformation during hot rolling is 70%, and then it is cooled. Subsequently, it is solution treated at 850°C and cooled. Then, it is aged at 550°C for 6 hours and cooled to obtain a plate. The plate is processed into a bipolar plate, and the surface of the bipolar plate is polished, cleaned, and dried to obtain a high-tungsten corrosion-resistant titanium alloy bipolar plate.

[0061] Preparation steps of fluorinated tungstate-bridged yttrium titanate complexes:

[0062] A1. Add 13.5g of sodium tungstate dihydrate to 100.0g of deionized water and stir until the sodium tungstate dihydrate is dispersed and dissolved. Add 3.0g of ammonium fluoride and continue stirring until the system is homogeneous. Adjust the pH to 4.5 with acetic acid to obtain an acidified fluorotungstate solution. Add 7.8g of yttrium hexahydrate to 40.0g of anhydrous ethanol and stir until dissolved to obtain an yttrium hexahydrate ethanol solution. Add the yttrium hexahydrate ethanol solution to the acidified fluorotungstate solution and stir at 50°C for 2 hours to obtain a tungsten-fluorine-yttrium composite solution. Add 6.8g of tetrabutyl titanate to 24.0g of anhydrous ethanol and stir until homogeneous to obtain a tetrabutyl titanate ethanol solution. Add the tetrabutyl titanate ethanol solution to the tungsten-fluorine-yttrium composite solution and stir at 60°C for 6 hours to obtain a tungsten-fluorine-titanium-yttrium composite sol.

[0063] A2. The tungsten-fluorine-titanium-yttrium composite sol was transferred into a hydrothermal reaction vessel and hydrothermally reacted at 160°C for 16 hours. After the reaction was completed, it was cooled to room temperature, the solid product was separated, washed with deionized water, and then dried at 80°C to obtain the precursor powder. The precursor powder was placed in a nitrogen protective atmosphere, heated to 400°C and held for 3 hours, cooled to room temperature, pulverized, and sieved to obtain the fluorinated tungstate-bridged yttrium titanate complex.

[0064] Preparation steps of tantalum-doped cerium oxide-coated tungsten carbide particles:

[0065] B1. Mix 62.0g ammonium paratungstate, 15.0g carbon black, and 100.0g deionized water, and ultrasonically disperse until the ammonium paratungstate and carbon black are uniformly dispersed. Dry to obtain tungsten carbide precursor powder. Place the tungsten carbide precursor powder in a mixed atmosphere of hydrogen and argon, heat to 1000°C and hold for 3 hours, then cool to room temperature to obtain tungsten carbide particles. Add 1.0g of tungsten carbide particles to a mixture of 75.0g deionized water and 60.0g anhydrous ethanol, and ultrasonically disperse until the tungsten carbide particles show no obvious agglomeration. Add 1.5g poloxamer 407, continue ultrasonic dispersion, and add 11.0g cerium nitrate hexahydrate. Stir until dissolved and uniformly dispersed. Dissolve 0.9g tantalum pentachloride in anhydrous ethanol to obtain an anhydrous ethanol solution containing 0.9g tantalum pentachloride. Add the anhydrous ethanol solution containing 0.9g tantalum pentachloride to the above system and stir until uniform to obtain a tungsten carbide-cerium-tantalum composite dispersion.

[0066] B2. Add ammonia dropwise to the tungsten carbide-cerium-tantalum composite dispersion to adjust the pH to 10.5, and stir at 70°C for 5 hours to obtain a tantalum-cerium deposited tungsten carbide composite. Transfer the tantalum-cerium deposited tungsten carbide composite to a hydrothermal reaction vessel and react hydrothermally at 180°C for 10 hours. After the reaction is completed, cool to room temperature, separate the solid product, wash and dry it to obtain a dry powder. Place the dry powder in an air atmosphere, heat it to 450°C and keep it at that temperature for 4 hours, cool it to room temperature, pulverize and sieve it to obtain tantalum-doped cerium oxide-coated tungsten carbide particles.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is that 2.5g of tungstate fluoride-bridged yttrium titanate complex and 3.0g of tantalum-doped cerium oxide-coated tungsten carbide particles are not added in step S1; otherwise, it is the same as Example 1.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 1 is that 2.5g of tungstate fluoride-bridged yttrium titanate complex is not added in step S1, but only 3.0g of tantalum-doped cerium oxide-coated tungsten carbide particles are added. The rest is the same as in Example 1.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that in step S1, 3.0g of tantalum-doped cerium oxide-coated tungsten carbide particles are not added, but only 2.5g of fluoride tungstate-bridged yttrium titanate complex is added. The rest is the same as in Example 1.

[0073] The performance of the high-tungsten corrosion-resistant titanium alloy bipolar plates provided in the above embodiments and comparative examples was tested using the following methods:

[0074] The bipolar plates prepared in Examples 1-3 and Comparative Examples 1-3 were processed into test samples of 20mm × 20mm × 1mm. Three parallel samples were tested for each sample. Before testing, the test surfaces were successively polished in the same direction with 800#, 1200#, and 2000# sandpaper, with each polishing time being 2 minutes. After polishing, the surface particles were rinsed with deionized water, and then ultrasonically cleaned in anhydrous ethanol for 15 minutes at an ultrasonic frequency of 40kHz. Subsequently, the samples were dried at 60°C for 2 hours. The non-test surfaces of the samples were sealed with corrosion-resistant insulating adhesive, leaving only 1.0 cm of the surface intact. 2 To test the area, the sample was used as the working electrode, a platinum sheet as the counter electrode, and a saturated calomel electrode as the reference electrode. Electrochemical corrosion tests were conducted in a 0.5 mol / L sulfuric acid solution, with the test temperature controlled at 80°C. Nitrogen gas was introduced into the test solution for 30 min before the test, and the sample was immersed in the test solution and then allowed to stand for 30 min.

[0075] The corrosion potential test uses the potential value after the open circuit potential has stabilized, and the unit is V.

[0076] Corrosion current density was obtained using potentiodynamic polarization curves, with a scan range of -1.0V to 2.0V and a scan rate of 1mV / s. The corrosion current density was obtained by fitting the polarization curves, and the unit is A·cm. -2 .

[0077] The corrosion rate is calculated based on the corrosion current density, sample density, and alloy equivalent electrochemical equivalent, and is expressed in mpy.

[0078] The 20-hour long-term current density test was conducted under the same test solution and 80°C conditions. The current density was continuously recorded during the 20-hour constant potential corrosion process, and the average value of the stable phase after the test was taken. The unit is A·cm. -2 .

[0079] After testing, the surface morphology was observed using a metallographic microscope at magnifications of 50×, 100×, 200×, and 500×. The focus was on recording whether there was pitting, corrosion grooves, flaking, or damage to the passivation film on the sample surface.

[0080] The performance test data above are shown in Table 1.

[0081] Table 1: Performance Test Results

[0082] As can be seen from the above, the corrosion current densities of Examples 1-3 are 1.02 × 10⁻⁶, respectively. -7 A·cm -2 4.56×10 -6 A·cm -2 and 1.80×10 -6 A·cm -2All were significantly lower than 8.62 × 10⁻⁶ in Comparative Example 1. -5 A·cm -2 Comparative Example 2: 1.44 × 10 -5 A·cm -2 Compared with Comparative Example 3, 7.00 × 10 -6 A·cm -2 This indicates that the simultaneous addition of tungstate-bridged yttrium titanate complex and tantalum-doped cerium oxide-coated tungsten carbide particles can significantly reduce the corrosion rate of high-tungsten titanium alloy bipolar plates in acidic water electrolysis environments.

[0083] The corrosion rates of Examples 1-3 were 0.035 mpy, 1.56 mpy, and 0.62 mpy, respectively, while Comparative Example 1 reached 29.6 mpy. This indicates that without the addition of tungstate fluoride-bridged yttrium titanate complex and tantalum-doped cerium oxide-coated tungsten carbide particles, the passivation structure on the surface of the titanium-based alloy is unstable and prone to rapid corrosion.

[0084] In Comparative Example 2, without the addition of fluorinated tungstate-bridged yttrium titanate complex, the corrosion rate increased to 4.935 mpy, indicating that the compound has a significant effect on inhibiting local enrichment of tungsten, improving the interfacial bonding between tungsten powder and titanium matrix, and reducing local corrosion.

[0085] Comparative Example 3, without the addition of tantalum-doped cerium oxide-coated tungsten carbide particles, showed an increased corrosion rate of 2.506 mpy, indicating that these particles play a crucial role in improving surface corrosion resistance and maintaining the continuity of the conductive and corrosion-resistant phase. The 20-hour long-term current densities for Examples 1-3 were 1.20 × 10⁻⁶ and 1.20 × 10⁻⁶, respectively. -6 A·cm -2 4.80×10 -6 A·cm -2 and 1.80×10 -6 A·cm -2 The values ​​are all lower than those of comparative examples 1-3, indicating that the high tungsten corrosion-resistant titanium alloy bipolar plate prepared by the present invention has smaller current fluctuations and lower degree of damage to the surface passivation film during long-term polarization.

[0086] The surface morphology after testing showed that the surface of Example 1 was continuous and without flaking, Example 2 had only slight corrosion marks, and the passivation film of Example 3 remained relatively intact; while Comparative Example 1 showed more pitting and corrosion spots, Comparative Example 2 showed local corrosion grooves, and Comparative Example 3 had slight peeling and local corrosion points.

[0087] The above results indicate that the present invention solves the problems of uneven tungsten distribution, insufficient continuity of surface passivation film, severe local corrosion, high long-term current density, and easy surface peeling after service in existing high-tungsten titanium alloy bipolar plates by the synergistic effect of tungsten fluoride bridging yttrium titanate complex and tantalum-doped cerium oxide-coated tungsten carbide particles. This enables the high-tungsten corrosion-resistant titanium alloy bipolar plate to have both lower corrosion current density, lower corrosion rate, and better long-term corrosion stability.

Claims

1. A method for preparing a high-tungsten corrosion-resistant titanium alloy bipolar plate, characterized in that the steps include... include: S1. By weight, mix 60.0-75.0 parts of sponge titanium powder, 12.0-20.0 parts of tungsten powder, 2.0-4.0 parts of aluminum powder, 1.5-3.0 parts of niobium powder, 1.0-2.5 parts of molybdenum powder, and 0.5-1.5 parts of chromium powder to obtain a basic alloy powder; add 1.5-3.5 parts of fluoride tungstate-bridged yttrium titanate complex and 2.0-4.0 parts of tantalum-doped cerium oxide-coated tungsten carbide particles to the basic alloy powder, and continue mixing to obtain a composite alloy powder; subject the composite alloy powder to cold isostatic pressing to obtain a billet; S2. Place the billet in a hot pressing sintering mold and sinter it under a vacuum atmosphere to obtain a sintered billet; then hot-roll the sintered billet and cool it. The solution is then subjected to a solution treatment and cooled; an aging treatment is then performed and cooled to obtain the sheet material; the sheet material is then processed into bipolar plates, and the surface is polished, cleaned, and dried.

2. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 1, characterized in that, In step S1, the pressure of the cold isostatic pressing is 200-250 MPa.

3. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 1, characterized in that, In step S2, the hot pressing sintering step includes: under a vacuum degree of 1×10 -3 -5×10 -3 Under Pa, the temperature is raised to 1180-1220℃, and a pressure of 30-40MPa is applied simultaneously for heat and pressure holding; the hot rolling step includes: heating the sintered billet to 950-1000℃ and holding it at that temperature; the solution treatment step includes: holding it at 800-850℃; the aging treatment step includes: holding it at 500-550℃.

4. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 1, characterized in that, The preparation method of the fluorinated tungstate-bridged yttrium titanate complex includes: A1. By weight, mix 6.5-13.5 parts of sodium tungstate dihydrate and 80.0-100.0 parts of deionized water, add 1.4-3.0 parts of ammonium fluoride, stir, and adjust the pH to 3.5-4.5 with acetic acid to obtain an acidified fluorotungstate solution; dissolve 3.8-7.8 parts of yttrium nitrate hexahydrate in 24.0-40.0 parts of anhydrous ethanol, add the acidified fluorotungstate solution, and stir at 40-50℃ to obtain a tungsten-fluorine-yttrium composite solution; mix 3.4-6.8 parts of tetrabutyl titanate and 16.0-24.0 parts of anhydrous ethanol, add to the tungsten-fluorine-yttrium composite solution, and stir at 50-60℃ to obtain a tungsten-fluorine-titanium-yttrium composite sol; A2. The tungsten-fluorine-titanium-yttrium composite sol is subjected to a hydrothermal reaction, cooled, separated, washed, and dried to obtain precursor powder; under a nitrogen protective atmosphere, the precursor powder is heated to 350-400℃ and held at that temperature, then cooled, pulverized, and sieved.

5. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 4, characterized in that, In step A1, the stirring time is 1-2 hours at 40-50℃ and 4-6 hours at 50-60℃.

6. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 4, characterized in that, In step A2, the hydrothermal reaction temperature is 140-160℃, the hydrothermal reaction time is 12-16h; the drying temperature is 60-80℃; and the holding time at 350-400℃ is 2-3h.

7. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 1, characterized in that, The preparation method of the tantalum-doped cerium oxide-coated tungsten carbide particles includes: B1. By weight, mix 30.0-62.0 parts ammonium paratungstate, 10.0-15.0 parts carbon black and 80.0-100.0 parts deionized water, disperse by ultrasonication, and dry to obtain tungsten carbide precursor powder; under a mixed atmosphere of hydrogen and argon, heat the tungsten carbide precursor powder to 950-1000℃ and hold for a period of time, then cool to obtain tungsten carbide particles; disperse 0.5-1.0 parts of tungsten carbide particles in a mixture of 50.0-75.0 parts deionized water and 40.0-60.0 parts anhydrous ethanol, add 1.0-1.5 parts poloxamer 407, disperse by ultrasonication, add 6.5-11.0 parts cerium nitrate hexahydrate and an anhydrous ethanol solution containing 0.5-0.9 parts tantalum pentachloride, stir to obtain tungsten carbide cerium tantalum composite dispersion; B2. Add ammonia dropwise to the tungsten carbide-cerium-tantalum composite dispersion to adjust the pH to 9.5-10.5, and stir at 60-70℃ to obtain a tantalum-cerium deposited tungsten carbide composite. Perform a hydrothermal reaction on the tantalum-cerium deposited tungsten carbide composite, cool, separate, wash, and dry to obtain a dry powder. In an air atmosphere, heat the dry powder to 400-450℃ and keep it at that temperature, then cool, pulverize, and sieve.

8. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 7, characterized in that, In step B1, the temperature is raised to 950-1000℃ and held for 2-3 hours.

9. The method for preparing the high-tungsten corrosion-resistant titanium alloy bipolar plate according to claim 7, characterized in that, In step B2, the stirring time at 60-70℃ is 4-5 hours; the temperature of the hydrothermal reaction is 160-180℃, and the hydrothermal reaction time is 8-10 hours; the holding time at 400-450℃ is 3-4 hours.

10. A high-tungsten corrosion-resistant titanium alloy bipolar plate, characterized in that, The high-tungsten corrosion-resistant titanium alloy bipolar plate is prepared by the method described in any one of claims 1-9.

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