Method for producing high-dielectric composite powder sintered foil

Abstract

The present invention provides a method for producing a highly dielectric composite powder sintered foil, which includes the steps of mixing aluminum powder, adhesive, and additives in an organic solvent and stirring to obtain a mixed slurry, applying the mixed slurry to the surface of an aluminum foil and drying and solidifying it to form a film to form a sintered foil, sintering the sintered foil base material to obtain a powder sintered foil, immersing the powder sintered foil in a titanium-containing precursor solution, then draining and performing a high-temperature sintering process to obtain a composite sintered foil, and performing a chemical conversion treatment on the composite sintered foil. In the manufacturing process of the present invention, there is no need to perform a hole expansion process on the aluminum foil by surface corrosion, so there is no need to use a large amount of acid solution. In addition, the dielectric properties of the electrode foil can be improved. In addition, after the hydrophilization treatment, the gel precursor solution produced is more easily attached to the powder sintered foil, the amount of titanium oxide carried is increased, and good bonding strength between the titanium dioxide and the aluminum foil gas after molding is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of manufacturing electrode foils, and particularly relates to a method for manufacturing a high-dielectric composite powder sintered foil.

Background Art

[0002] The electrode foils used in conventional aluminum electrolytic capacitors increase the specific surface area by chemically and electrochemically etching (etching) aluminum foils to form holes. This method requires the use of a large amount of acid solution, and generates waste liquid, resulting in an increase in environmental protection costs. In recent years, instead of electrochemical corrosion, a method has emerged to obtain a high specific surface area by sintering aluminum powder on the surface of an aluminum substrate. As a result of research, it has been found that powder sintered foils can obtain a larger specific surface area compared to etched foils, and do not use various corrosive acids in the manufacturing process, thus significantly reducing the environmental load and economic costs.

[0003] In recent years, researchers have confirmed that adding a high-dielectric material to an aluminum electrode foil is an effective means to increase the area specific capacitance of the aluminum electrode foil. For example, Chinese Patent CN106384670B discloses a method for manufacturing a composite oxide film electrode foil with a high dielectric constant. Specifically, an aluminum foil subjected to surface expansion corrosion is immersed in a mixed system of n-butyl titanate and ethylene glycol methyl ether prepared by the sol-gel method at 50 to 70 °C, and then a DC voltage of 5 to 10 V is applied to the mixed system, and 30 to 60 mA / cm 2Electrodeposit for 0.5 to 2 minutes at a current density, then dry in an air atmosphere at 100 to 200 °C for 3 to 5 minutes, perform a high-temperature heat treatment at 400 to 600 °C for 1 to 24 hours with a protective gas powder under a pressure of 1 to 3 atm, and perform chemical conversion (anodic oxidation). The volume ratio of the n-butyl titanate to the ethylene glycol methyl ether is 1:3 to 5. After the mixed solution is subjected to a chelation reaction at 40 to 80 °C for 12 to 24 hours, pure water is added to adjust the concentration of the solution to 0.1 to 1 mol / L. In actual experimental results, the electrode foil manufactured by the above method can improve the area specific capacitance by 20% or more compared with the prior art. However, in the process of surface expansion of the aluminum foil, a large amount of acid and electrical energy are required. Also, in order to eliminate environmental pollution, the factory has to spend a large amount of additional costs to purchase waste acid treatment equipment. Furthermore, it is difficult to control parameters such as the pore diameter, depth, and distribution density uniformity of the pores formed on the surface of the aluminum foil, which will inevitably affect the formation quality of the titanium-containing high-dielectric-constant composite oxide film and the bonding strength of the aluminum foil substrate. Therefore, the high-dielectric-constant composite oxide film manufactured by the prior art is likely to peel off from the aluminum foil substrate due to vibration force or external force, reducing the performance of the aluminum electrolytic capacitor. Therefore, it is an urgent task for those skilled in the art to solve the problems of the prior art.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Considering the above problems and drawbacks of the prior art, the designer of the present invention collected relevant information, evaluated and considered many aspects, and further continuously experimented and modified by technicians with many years of research and development experience in this industry. Finally, a method for manufacturing a high-dielectric composite powder sintered foil was found.

Means for Solving the Problems

[0005] To solve the above problems of the prior art, the present invention provides a method for manufacturing a high-dielectric composite powder sintered foil, comprising: Step S1 of mixing aluminum powder, an adhesive, and an additive in an organic solvent and uniformly stirring to obtain a mixed slurry; applying the mixed slurry obtained in Step S1 onto the surface of an aluminum foil, drying and solidifying to form a film, Sintered foil substrate Step S2 of forming; Step S3 of placing the sintered foil substrate obtained in Step S2 in an inert gas and sintering to obtain a powder sintered foil; Step S4 of immersing the powder sintered foil obtained in Step S3 in a titanium-containing precursor solution, performing a draining process, and then performing a heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil; and Step S5 of forming the high-dielectric composite powder sintered foil by forming the composite sintered foil obtained in Step S4. The method for manufacturing the titanium-containing precursor solution includes the following sub-steps: adding a tetrabutyl titanate solution drop by drop to a lactic acid solution and stirring for 3 to 5 minutes to form a mixed solution, where the volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6 and the concentration of the tetrabutyl titanate solution is 0.01 to 0.5 mol / L, Sub-step S41; Sub-step S42 of adding deionized water to the mixed solution obtained in Step S41 for dilution and uniformly stirring; and Sub-step S43 of continuously adding an aqueous polyvinyl alcohol solution with a concentration of 0.2 to 0.5 g / L to the mixed solution and stirring for 3 to 5 minutes until uniformly mixed. A method for manufacturing a high-dielectric composite powder sintered foil is provided.

[0006] As a further improvement of the technical solution disclosed in the present invention, in Step S1, the adhesive is any one or a combination thereof of epoxy resin, polyvinylidene fluoride, carboxymethyl cellulose, or acrylic resin.

[0007] As a further improvement of the technical solution disclosed in the present invention, in Step S1, the additive is any one or a combination thereof of sodium dodecylbenzenesulfonate, stearic acid, or polyvinyl alcohol.

[0008] As a further improvement of the technical solution disclosed in the present invention, in step S1, the organic solvent is any one or a combination of ethanol, ethylene glycol, glycerin, and N-methylpyrrolidone.

[0009] As a further improvement of the technical solution disclosed in the present invention, in step S2, the thickness of the aluminum foil is 30 to 80 μm, the surface roughness Ra is 0.2 to 0.25 μm, and the coating method of the mixed slurry is a brush coating, rolling coating or spray coating method. Drying and solidifying the mixed slurry to form a film The drying temperature is 150 to 200 °C.

[0010] As a further improvement of the technical solution disclosed in the present invention, step S3 includes sub-step S31 of placing the sintered foil substrate obtained in step S2 in an inert gas at a temperature of 300 to 450 °C and maintaining it for 1.5 to 2 h, and sub-step S32 of continuing to place the sintered foil substrate obtained in step S31 in an inert gas, heating it to 500 to 650 °C and maintaining it for 3 to 5 h.

[0011] As a further improvement of the technical solution disclosed in the present invention, the inert gas is nitrogen gas or argon gas.

[0012] As a further improvement of the technical solution disclosed in the present invention, in step S4, after draining the titanium-containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is 550 to 600 °C, and the heat preservation time is 25 to 30 min.

[0013] As a further improvement of the technical solution disclosed in the present invention, step S5 includes sub-step S51 of boiling the composite sintered foil in water at 90 to 95 °C for 8 to 10 min, and immersing the composite sintered foil obtained in step S51 in an aqueous boric acid solution with a mass percentage concentration of 2 to 10% and an ammonium pentaborate solution of 0.5 to 2%, at 70 to 90 °C, current density 20 mA / cm 2, under the condition of a voltage of 200 V, perform primary formation, control the formation time to 10 - 20 min, then take it out and wash it with water, sub-step S52, and immerse the composite sintered foil obtained in step S52 in an aqueous boric acid solution with a mass percentage concentration of 2 - 10% and an ammonium pentaborate solution with a mass percentage concentration of 0.2 - 1.5%, at 80 - 95 °C, current density 20 mA / cm 2 , under the condition of a voltage of 430 V, perform secondary formation, control the formation time to 10 - 15 min, then take it out and wash it with water, sub-step S53, and immerse the composite sintered foil obtained in step S53 in an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1%, at 80 - 95 °C, current density 20 mA / cm 2 , under the condition of a voltage of 590 V, perform tertiary formation, control the formation time to 8 - 15 min, then take it out and wash it with water, sub-step S54, and immerse the composite sintered foil obtained in step S54 in an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1%, at 80 - 95 °C, current density 20 mA / cm 2 , under the condition of a voltage of 620 V, perform quaternary formation, control the formation time to 20 - 30 min, then take it out and wash it with water, sub-step S55, and immerse the composite sintered foil obtained in step S55 in a phosphoric acid solution with a mass percentage concentration of 5 - 6%, control the temperature to 50 - 80 °C, control the immersion time to 5 - 10 min, then take it out and wash it with water, sub-step S56, and immerse the composite sintered foil obtained in step S56 in an aqueous boric acid solution with a mass percentage concentration of 10 - 12% and an ammonium pentaborate solution with a mass percentage concentration of 1 - 1.5%, at 80 - 95 °C, current density 20 mA / cm 2, perform post-primary formation under the condition of a voltage of 620 V, control the formation time to 5 - 8 min, then take it out and wash it with water, sub-step S57, and put the composite sintered foil obtained in step S57 into an oven, control the temperature to 400 - 550 °C, control the time to 3 - 5 min and dry it, step S58, and immerse the composite sintered foil obtained in step S58 in an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1%, at 80 - 95 °C, current density 20 mA / cm 2 , perform post-secondary formation under the condition of a voltage of 620 V, control the formation time to 7 - 10 min, then take it out and wash it with water, sub-step S59, and put the composite sintered foil obtained in step S59 into an ammonium dihydrogen phosphate solution with a mass percentage concentration of 1 - 5%, immerse it at 60 - 80 °C for 5 - 8 min, then take it out, wash it with water and dry it, sub-sub-step S60.

Advantages of the Invention

[0014] In actual application, the manufacturing method of the high-dielectric composite powder sintered foil has at least the following beneficial effects. 1) Compared with the conventional surface expansion corrosion electrodeposition process of forming a titanium composite oxide film on the surface of an aluminum foil, in the technology disclosed in the present application, since it is not necessary to perform surface corrosion and hole expansion treatment on the aluminum foil, the entire manufacturing process can suppress the use of a large amount of acidic solution, not only reducing the difficulty and cost of manufacturing the electrode foil to a certain extent, but also reducing the burden of waste acid treatment. 2) Due to the presence of titanium dioxide, the dielectric properties of the electrode foil are further improved, and the composite electrode foil can obtain higher area specific capacitance performance. 3) By performing a hydrophilic treatment, the produced gel precursor solution is likely to adhere to the powder sintered foil, not only making the surface quality and shape of the titanium dioxide film after forming uniform, but also the film phase of titanium dioxide and the aluminum foil substrate after forming have better bonding strength, and the peeling phenomenon from the aluminum foil substrate due to vibration force or external force can be effectively avoided.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, examples will be given to explain the present invention in more detail in order to deepen the understanding of the present invention. However, these examples are only used to explain the present invention and do not limit the protection scope of the present invention. In addition, in the following description, all are well-known technologies unless otherwise specifically described.

[0016] Example 1 The manufacturing method of the electrical composite powder sintered foil of the present invention includes the following steps.

[0017] S1. Mix aluminum powder, epoxy resin, and sodium dodecylbenzenesulfonate in ethanol, and stir evenly to obtain a mixed slurry. The mass ratio of each component in the mixed slurry is 60 - 85% aluminum powder, 5 - 10% epoxy resin, 1 - 5% sodium dodecylbenzenesulfonate, 6 - 30% ethanol, and the purity of the aluminum powder is 99.9% or more, and the particle size is controlled to be 1 - 50 μm.

[0018] S2. Apply the mixed slurry obtained in step S1 onto the surface of an aluminum foil with a thickness of 30 μm and a surface roughness Ra controlled to be 0.2 - 0.25 μm, and dry and solidify to form a film, forming a sintered foil Substrate The drying temperature for forming the solidified film of the mixed slurry is controlled to be 150°C.

[0019] S3. The forming of the powder sintered foil includes the following sub-steps.

[0020] S31. Place the sintered foil substrate obtained in step S2 in an argon atmosphere and maintain it at a temperature of 300°C for 2 hours.

[0021] S32. Continuously place the sintered foil substrate obtained in step S31 in an argon atmosphere, heat it up to 500°C and maintain it for 5 hours.

[0022] S4. Immerse the powder sintered foil obtained in step S3 into the titanium-containing precursor solution. After draining, perform heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil. After draining the titanium-containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is controlled at 550 °C, and the heat preservation time is 30 min.

[0023] The manufacturing method of the titanium-containing precursor solution includes the following sub-steps.

[0024] S41. Add the tetrabutyl titanate solution drop by drop to the lactic acid solution and stir for 3 - 5 min to form a mixed solution. The volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6, and the concentration of the tetrabutyl titanate solution is 0.05 - 0.1 mol / L.

[0025] S42. Add deionized water to the mixed solution obtained in step S41 for dilution and stir evenly.

[0026] S43. Continuously add an aqueous polyvinyl alcohol solution with a concentration of 0.2 - 0.5 g / L to the mixed solution and stir for 3 - 5 min until evenly mixed.

[0027] S5. Subject the composite sintered foil obtained in step S4 to formation by a conventional formation process to obtain a high-dielectric composite powder sintered foil.

[0028] The conventional formation process includes the following sub-steps.

[0029] S51. Immerse the composite sintered foil obtained in step S4 into a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 10 mA / cm 2 during formation, control the temperature in the solution tank at 90 °C to obtain a primary formed foil.

[0030] S52. Immerse the primary formed foil into a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 30 mA / cm 2Apply a current, control the temperature in the solution tank to 90 °C, and obtain a secondary conversion foil.

[0031] S53. Immerse the secondary conversion foil in a 5 wt% ammonium diacid solution for conversion (chemical corrosion, oxidation corrosion), and apply a current of 40 mA / cm during the conversion 2 Apply a current, control the temperature in the solution tank to 90 °C, and obtain a tertiary conversion foil.

[0032] S54. Immerse the tertiary conversion foil in a 25 wt% ammonium diacid solution for conversion (chemical corrosion, oxidation corrosion), and apply a current of 50 mA / cm during the conversion 2 Apply a current, control the temperature in the solution tank to 60 °C, repeat the conversion (chemical corrosion, oxidation corrosion) multiple times, and the current density for the fourth to sixth times is 50 mA / cm 2 to obtain a sixth conversion foil.

[0033] S55. Perform a depolarization treatment on the obtained sixth conversion foil.

[0034] Example 2 A method for manufacturing a high-dielectric composite powder sintered foil, comprising the following steps.

[0035] S1. Mix aluminum powder, epoxy resin, and sodium dodecylbenzenesulfonate in ethanol, stir uniformly to obtain a mixed slurry. The mass ratio of each component in the mixed slurry is controlled such that the aluminum powder is 60 - 85%, the epoxy resin is 5 - 10%, the sodium dodecylbenzenesulfonate is 1 - 5%, the ethanol is 6 - 30%, and the purity of the aluminum powder is controlled to be 99.9% or more, and the particle size is controlled to be 1 - 50 μm.

[0036] S2. Apply the mixed slurry obtained in step S1 onto the surface of an aluminum foil with a thickness of 30 μm and a surface roughness Ra of 0.2 - 0.25 μm, dry and solidify to form a film, and form a sintered foil Substrate The drying temperature for forming the solidified film of the mixed slurry is controlled to be 180 °C.

[0037] S3. The forming of the powder sintered foil includes the following sub-steps.

[0038] S31. Place the sintered foil substrate obtained in step S2 in an argon atmosphere, control the temperature to 450 °C, and maintain it for 1.5 h.

[0039] S32. Continue to place the sintered foil substrate obtained in step S31 in an argon atmosphere, heat it up to 650 °C and maintain it for 3 h.

[0040] S4. Immerse the powder sintered foil obtained in step S3 in a titanium-containing precursor solution, drain it, and then perform heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil. After draining the titanium-containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is controlled to 600 °C, and the heat preservation time is 25 min.

[0041] The manufacturing method of the titanium-containing precursor solution includes the following sub-steps.

[0042] S41. Add tetrabutyl titanate solution drop by drop to the lactic acid solution and stir for 3 - 5 min to form a mixed solution. The volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6, and the concentration of the tetrabutyl titanate solution is 0.05 - 0.1 mol / L.

[0043] S42. Add deionized water to the mixed solution obtained in step S41 to dilute it and stir evenly.

[0044] S43. Continuously add an aqueous solution of polyvinyl alcohol with a concentration of 0.2 - 0.5 g / L to the mixed solution and stir for 3 - 5 min until it is evenly mixed.

[0045] S5. Subject the composite sintered foil obtained in step S4 to formation by a conventional formation process to obtain a high dielectric composite powder sintered foil.

[0046] The conventional formation process includes the following sub-steps.

[0047] S51. Immerse the composite sintered foil obtained in step S4 in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 10 mA / cm 2 during the formation, control the temperature in the solution tank at 90 °C to obtain a primary formed foil.

[0048] S52. Immerse the primary formed foil in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 30 mA / cm 2 during the formation, control the temperature in the solution tank at 90 °C to obtain a secondary formed foil.

[0049] S53. Immerse the secondary formed foil in a 5 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 40 mA / cm 2 during the formation, control the temperature in the solution tank at 90 °C to obtain a tertiary formed foil.

[0050] S54. Immerse the tertiary formed foil in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 50 mA / cm 2 during the formation, control the temperature in the solution tank at 60 °C, repeat the formation (chemical corrosion, oxidation corrosion) multiple times, and the current density for the fourth to sixth times is 50 mA / cm 2 to obtain a sixth formed foil thereby.

[0051] S55. Perform a depolarization treatment on the obtained sixth formed foil.

[0052] Example 3 The method for manufacturing a high-dielectric composite powder sintered foil includes the following steps.

[0053] S1. Mix aluminum powder, epoxy resin, sodium dodecylbenzenesulfonate in ethanol, and stir uniformly to obtain a mixed slurry. The mass ratio of each component in the mixed slurry is controlled such that aluminum powder is 60 - 85%, epoxy resin is 5 - 10%, sodium dodecylbenzenesulfonate is 1 - 5%, ethanol is 6 - 30%, and the purity of the aluminum powder is controlled to be 99.9% or more, and the particle size is controlled to be 1 - 50 μm.

[0054] S2. Apply the mixed slurry obtained in step S1 onto the surface of an aluminum foil with a thickness of 30 μm and a surface roughness Ra of 0.2 - 0.25 μm, and dry and cure it to form a film to obtain a sintered foil. Substrate The drying temperature for forming the cured film of the mixed slurry is controlled at 180°C.

[0055] S3. Forming the powder sintered foil, including the following sub - steps: S31. Place the sintered foil substrate obtained in step S2 in an argon atmosphere, control the temperature at 350°C, and maintain it for 1.8 h.

[0056] S32. Continuously place the sintered foil substrate obtained in step S31 in an argon atmosphere, heat it up to 550°C, and maintain it for 4 h.

[0057] S4. Immerse the powder sintered foil obtained in step S3 in a titanium - containing precursor solution, drain it, and then perform heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil. After draining the titanium - containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is controlled at 600°C, and the heat - preservation time is 25 min.

[0058] The manufacturing method of the titanium - containing precursor solution includes the following sub - steps.

[0059] S41. Add the tetrabutyl titanate solution drop by drop to the lactic acid solution, and stir for 3 - 5 min to form a mixed solution. The volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6, and the concentration of the tetrabutyl titanate solution is 0.05 - 0.1 mol / L.

[0060] S42. Add deionized water to the mixed solution obtained in step S41 for dilution, and stir uniformly.

[0061] S43. Subsequently, add an aqueous polyvinyl alcohol solution with a concentration of 0.2 - 0.5 g / L to the mixed solution, and stir for 3 - 5 min until uniformly mixed. S5. Subject the composite sintered foil obtained in step S4 to formation by a conventional formation process to obtain a high - dielectric composite powder sintered foil.

[0062] The conventional formation process includes the following sub - steps.

[0063] S51. Immerse the composite sintered foil obtained in step S4 in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 10 mA / cm 2 during formation, control the temperature in the solution tank at 90 °C, and obtain a primary formed foil.

[0064] S52. Immerse the primary formed foil in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 30 mA / cm 2 during formation, control the temperature in the solution tank at 90 °C, and obtain a secondary formed foil.

[0065] S53. Immerse the secondary formed foil in a 5 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 40 mA / cm 2 during formation, control the temperature in the solution tank at 90 °C, and obtain a tertiary formed foil.

[0066] S54. Immerse the tertiary formed foil in a 25 wt% ammonium diacid solution for formation (chemical corrosion, oxidation corrosion), apply a current with a current density of 50 mA / cm 2 during formation, control the temperature in the solution tank at 60 °C, repeat formation (chemical corrosion, oxidation corrosion) multiple times, with the current density for the fourth to sixth times being 50 mA / cm 2 and obtain a sixth - formed foil.

[0067] S55. Perform a depolarization treatment on the obtained sixth anodized foil.

[0068] Example 4 The method for manufacturing a high-dielectric composite powder sintered foil includes the following steps.

[0069] S1. Mix aluminum powder, epoxy resin, and sodium dodecylbenzenesulfonate in ethanol, and stir uniformly to obtain a mixed slurry. The mass ratio of each component in the mixed slurry is controlled such that the aluminum powder is 60 - 85%, the epoxy resin is 5 - 10%, the sodium dodecylbenzenesulfonate is 1 - 5%, and the ethanol is 6 - 30%. Also, the purity of the aluminum powder is controlled to be 99.9% or more, and the particle size is controlled to be 1 - 50 μm.

[0070] S2. Apply the mixed slurry obtained in step S1 onto the surface of an aluminum foil with a thickness of 30 μm and a surface roughness Ra of 0.2 - 0.25 μm, and dry and cure it to form a film, thereby forming a sintered foil. Substrate The drying temperature for forming the mixed slurry cured film is controlled to be 180°C.

[0071] S3. The forming of the powder sintered foil includes the following sub-steps.

[0072] S31. Place the sintered foil substrate obtained in step S2 in an argon atmosphere, control the temperature to 350°C, and maintain it for 1.8 h.

[0073] S32. Continuously place the sintered foil substrate obtained in step S31 in an argon atmosphere, heat it up to 550°C, and maintain it for 4 h.

[0074] S4. Immerse the powder sintered foil obtained in step S3 in a titanium-containing precursor solution, perform a draining treatment, and then conduct a heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil. After draining the titanium-containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is controlled to be 600°C, and the heat preservation time is set to 25 min.

[0075] The method for manufacturing the titanium-containing precursor solution includes the following sub-steps.

[0076] S41. Add the tetrabutyl titanate solution drop by drop to the lactic acid solution and stir for 3 - 5 min to form a mixed solution. The volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6, and the concentration of the tetrabutyl titanate solution is 0.05 - 0.1 mol / L.

[0077] S42. Add deionized water to the mixed solution obtained in step S41 for dilution and stir uniformly.

[0078] S43. Continuously add an aqueous polyvinyl alcohol solution with a concentration of 0.2 - 0.5 g / L to the mixed solution and stir for 3 - 5 min until uniformly mixed.

[0079] S5. Subject the composite sintered foil obtained in step S4 to forming by a conventional forming process to obtain a high-dielectric composite powder sintered foil.

[0080] Step S5 includes the following sub-steps.

[0081] S51. Boil the composite sintered foil in water at 90 - 95 °C for 8 - 10 min.

[0082] S52. Immerse the composite sintered foil obtained in step S51 in an aqueous boric acid solution with a mass percentage concentration of 2 - 10% and an ammonium pentaborate solution with a concentration of 0.5 - 2%, and perform primary forming (chemical corrosion, oxidation corrosion) under the conditions of 70 - 90 °C, a current density of 20 mA / cm 2 , a voltage of 200 V, control the forming time to be 10 - 20 min, and then take it out and wash it with water.

[0083] S53. Immerse the composite sintered foil obtained in step S52 in an aqueous boric acid solution with a mass percentage concentration of 2 - 10% and an ammonium pentaborate solution with a mass percentage concentration of 0.2 - 1.5%, and at 80 - 95 °C, a current density of 20 mA / cm 2, under the condition of a voltage of 430V, perform secondary formation (chemical corrosion, oxidation corrosion), control the formation time to 10 - 15 minutes, then take it out and wash it with water.

[0084] S54. Immerse the composite sintered foil obtained in step S53 in an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1% at 80 - 95°C and a current density of 20 mA / cm 2 , under the condition of a voltage of 590V, perform tertiary formation (chemical corrosion, oxidation corrosion), control the formation time to 8 - 15 minutes, then take it out and wash it with water.

[0085] S55. Immerse the composite sintered foil obtained in step S54 in an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1% at 80 - 95°C and a current density of 20 mA / cm 2 , under the condition of a voltage of 620V, perform quaternary formation (chemical corrosion, oxidation corrosion), control the formation time to 20 - 30 minutes, then take it out and wash it with water.

[0086] S56. Immerse the composite sintered foil obtained in step S55 in a phosphoric acid solution with a mass percentage concentration of 5 - 6%, control the temperature to 50 - 80°C, control the immersion time to 5 - 10 minutes, then take it out and wash it with water.

[0087] S57. Immerse the composite sintered foil obtained in step S56 in an aqueous boric acid solution with a mass percentage concentration of 10 - 12% and an ammonium pentaborate solution with a mass percentage concentration of 1 - 1.5% at 80 - 95°C and a current density of 20 mA / cm 2 , under the condition of a voltage of 620V, perform primary formation (chemical corrosion, oxidation corrosion), control the formation time to 5 - 8 minutes, then take it out and wash it with water.

[0088] S58. Put the composite sintered foil obtained in step S57 into an oven, control the temperature to 400 - 550°C, and control the time to 3 - 5 minutes.

[0089] S59. Place the composite sintered foil obtained in step S58 into an aqueous boric acid solution with a mass percentage concentration of 4 - 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 - 1%, and perform secondary formation (chemical corrosion, oxidation corrosion) under the conditions of 80 - 95 °C and a current density of 20 mA / cm 2 , a voltage of 620 V, with the formation time controlled to be 7 - 10 min, and then take it out and wash it with water.

[0090] S60. Immerse the composite sintered foil obtained in step S59 into an ammonium dihydrogen phosphate solution with a mass percentage concentration of 1 - 5%, immerse it for 5 - 8 min under the conditions of 60 - 80 °C, then take it out, wash it with water, and dry it.

[0091] Table 1 shows the performance test results of the electrode foils obtained in the prior art and Examples 1 - 4.

[0092] Table 1 JPEG0007701997000001.jpg49155 Remarks: 1) The manufacturing process of the existing electric foil is implemented with reference to the content related to the second embodiment described in the specification of Chinese Patent CN106384670B.

[0093] 2) The peel area was tested using the method of ISO2409 - 1992 "Cross - cut Test for Paints and Varnishes".

[0094] In actual applications, the manufacturing method of the high - permittivity composite powder sintered foil achieves at least the following advantageous effects.

[0095] 1) Compared with the conventional surface - enlarged corrosion electrodeposition process of forming a titanium composite oxide film on the aluminum foil surface, in the technology disclosed in this application, since it is not necessary to perform surface corrosion and hole - enlargement treatment on the aluminum foil surface, the entire manufacturing process can suppress the use of a large amount of acidic solution. This not only reduces the difficulty and cost of manufacturing the electrode foil to a certain extent but also reduces the burden of waste acid treatment. Also, because the powder sintered foil has a large specific surface area, the non - volume performance can be improved.

[0096] 2) Due to the presence of titanium dioxide, the dielectric properties of the electrode foil are further improved, and the composite electrode foil can obtain higher area-specific capacitance performance.

[0097] 3) By performing a hydrophilic treatment, the produced gel precursor solution easily adheres to the powder sintered foil, not only making the surface quality and shape of the titanium dioxide film after forming uniform, but also the film phase of the titanium dioxide and the aluminum foil substrate after forming have better bonding strength, and the peeling phenomenon from the aluminum foil substrate caused by vibration force or external force can be effectively avoided.

[0098] It should be noted that the difference between the fourth embodiment of the present invention and the above-described first, second, and third embodiments is that it discloses a forming method different from the conventional one. Specifically, in step S5, the composite sintered foil is formed by mixing boric acid and ammonium pentaborate, and the forming process is performed in a plurality of stages (specifically, including primary forming (chemical corrosion, oxidation corrosion), secondary forming, tertiary forming, quaternary forming, post-primary forming, and post-secondary forming). The fine structure of the oxide film obtained in such a forming process is denser, which is advantageous for improving the bonding strength between the high-dielectric-constant titanium dioxide and the aluminum oxide film and the overall bending performance after composite. In actual application, through multiple bends, it is possible to effectively avoid the connection breakage or damage of the composite film (formed by the composite of high-dielectric-constant titanium dioxide and aluminum oxide film) or the peeling of the composite film from the high-dielectric composite powder sintered foil over a large area.

[0099] From the description of the disclosed embodiments, those skilled in the art can manufacture or use the present invention. Various modifications to these embodiments are easy for those skilled in the art, and the general principles defined in this specification can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown in detail of the invention, but also includes the broadest scope consistent with its principles and features.

Claims

1. A method for manufacturing a high-dielectric composite powder sintered foil, comprising: Step S1 of mixing aluminum powder, an adhesive, and an additive in an organic solvent and uniformly stirring to obtain a mixed slurry; Step S2 of applying the mixed slurry obtained in Step S1 onto the surface of an aluminum foil, drying and solidifying to form a film, thereby forming a sintered foil substrate; Step S3 of placing the sintered foil substrate obtained in Step S2 in an inert gas and sintering to obtain a powder sintered foil; Step S4 of immersing the powder sintered foil obtained in Step S3 in a titanium-containing precursor solution, performing a draining process, and then performing a heat treatment to form titanium dioxide on the surface of the powder sintered foil to obtain a composite sintered foil; Step S5 of forming the composite sintered foil obtained in Step S4 into a high-dielectric composite powder sintered foil by forming; The method for manufacturing the titanium-containing precursor solution includes the following sub-steps: Sub-step S41 of adding a tetrabutyl titanate solution drop by drop to a lactic acid solution and stirring for 3 to 5 minutes to form a mixed solution, where the volume ratio of the tetrabutyl titanate solution to the lactic acid solution is 1:6, and the concentration of the tetrabutyl titanate solution is 0.01 to 0.5 mol / L; Sub-step S42 of adding deionized water to the mixed solution obtained in Step S41 for dilution and uniformly stirring; Sub-step S43 of continuously adding an aqueous polyvinyl alcohol solution with a concentration of 0.2 to 0.5 g / L to the mixed solution and stirring for 3 to 5 minutes until uniformly mixed. A method for manufacturing a high-dielectric composite powder sintered foil, characterized by the above.

2. In Step S1, the mass ratio of each component in the mixed slurry is such that the aluminum powder is 60 to 85%, the adhesive is 5 to 10%, the additive is 1 to 5%, and the organic solvent is 6 to 30%. The method for manufacturing a high-dielectric composite powder sintered foil according to Claim 1, characterized by the above.

3. In Step S1, the purity of the aluminum powder is 99.9% or more, and the particle size is 1 to 50 μm. The method for manufacturing a high-dielectric composite powder sintered foil according to Claim 2, characterized by the above.

4. In Step S1, the adhesive is any one or a combination of epoxy resin, polyvinylidene fluoride, carboxymethyl cellulose, or acrylic resin. The method for manufacturing a high-dielectric composite powder sintered foil according to Claim 2, characterized by the above.

5. In step S1, the additive is any one or a combination thereof of sodium dodecylbenzenesulfonate, stearic acid, or polyvinyl alcohol, and the method for manufacturing the high-dielectric composite powder sintered foil according to claim 2 is characterized in this.

6. In step S1, the organic solvent is any one or a combination thereof of ethanol, ethylene glycol, glycerin, or N-methylpyrrolidone, and the method for manufacturing the high-dielectric composite powder sintered foil according to claim 2 is characterized in this.

7. In step S2, the thickness of the aluminum foil is 30 to 80 μm, the surface roughness Ra is 0.2 to 0.25 μm, the coating method of the mixed slurry is a brush coating, rolling coating, or spray coating method, and the drying temperature for drying and solidifying the mixed slurry to form a film is 150 to 200 °C, and the method for manufacturing the high-dielectric composite powder sintered foil according to claim 1 is characterized in this.

8. The step S3 is sub-step S31 of placing the sintered foil substrate obtained in step S2 in an inert gas, maintaining the temperature at 300 to 450 °C for 1.5 to 2 h, and sub-step S32 of continuously placing the sintered foil substrate obtained in sub-step S31 in an inert gas, raising the temperature to 500 to 650 °C and maintaining it for 3 to 5 h, and the method for manufacturing the high-dielectric composite powder sintered foil according to claim 1 is characterized in this.

9. In step S4, after draining the titanium-containing precursor solution, the heat treatment temperature for manufacturing the composite sintered foil is 550 to 600 °C, and the heat preservation time is 25 to 30 min, and the method for manufacturing the high-dielectric composite powder sintered foil according to claim 1 is characterized in this.

10. Step S5 is sub-step S51 of boiling the composite sintered foil in water at 90 to 95 °C for 8 to 10 min, and The composite sintered foil obtained in step S51 is immersed in an aqueous boric acid solution with a mass percentage concentration of 2 to 10% and an ammonium pentaborate solution of 0.5 to 2%, and primary formation is carried out at 70 to 90 °C under a current density of 20 mA / cm ２ , a voltage of 200 V, the formation time is controlled to be 10 to 20 min, then taken out and washed with water, sub-step S52, and The composite sintered foil obtained in step S52 is immersed in an aqueous boric acid solution with a mass percentage concentration of 2 to 10% and an ammonium pentaborate solution with a mass percentage concentration of 0.2 to 1.5%, and at 80 to 95 ° C, a current density of 20 mA / cm ２ , secondary formation is carried out under the conditions of a voltage of 430 V, the formation time is controlled to be 10 to 15 minutes, and then it is taken out and washed with water, sub-step S53, and The composite sintered foil obtained in step S53 is immersed in an aqueous boric acid solution with a mass percentage concentration of 4 to 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 to 1%, and at 80 to 95 °C, a current density of 20 mA / cm ２ , three times of formation is carried out under the conditions of a voltage of 590 V, the formation time is controlled to be 8 to 15 min, then taken out and washed with water, sub-step S54, and The composite sintered foil obtained in step S54 is immersed in an aqueous boric acid solution with a mass percentage concentration of 4 to 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 to 1%, and is subjected to four - step formation at 80 to 95 °C, a current density of 20 mA / cm ２ , under the condition of a voltage of 620 V, the formation time is controlled to be 20 to 30 min, then taken out and washed with water, sub - step S55, and sub-step S56 of immersing the composite sintered foil obtained in step S55 in a phosphoric acid solution with a mass percentage concentration of 5 to 6%, controlling the temperature at 50 to 80 °C, controlling the immersion time at 5 to 10 min, and then taking it out and washing it with water, and The composite sintered foil obtained in step S56 is immersed in an aqueous boric acid solution with a mass percentage concentration of 10 to 12% and an ammonium pentaborate solution with a mass percentage concentration of 1 to 1.5%, and at 80 to 95 °C and a current density of 20 mA / cm ２ , a subsequent formation is carried out under the conditions of a voltage of 620 V, the formation time is controlled to be 5 to 8 min, and then it is taken out and washed with water, sub-step S57, and step S58 of putting the composite sintered foil obtained in step S57 into an oven, controlling the temperature at 400 to 550 °C, controlling the time at 3 to 5 min, and drying it The composite sintered foil obtained in step S58 is immersed in an aqueous boric acid solution with a mass percentage concentration of 4 to 9% and an ammonium pentaborate solution with a mass percentage concentration of 0.1 to 1%, and at 80 to 95 °C, a current density of 20 mA / cm ２ , under the conditions of a voltage of 620 V, post-secondary formation is performed, the formation time is controlled to be 7 to 10 minutes, and then it is taken out and washed with water, sub-step S59, and The method for manufacturing a high-dielectric composite powder sintered foil according to claim 1, characterized by including sub-step S60 of putting the composite sintered foil obtained in step S59 into an ammonium dihydrogen phosphate solution with a mass percentage concentration of 1 to 5%, immersing it at 60 to 80°C for 5 to 8 minutes, then taking it out, washing it with water, and drying it.

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