Foam metal growing on polymer substrate and preparation method thereof

Abstract

The invention relates to a foam metal growing on a polymer substrate and a preparation method thereof. Comprising the following steps: 1) a base material preparation stage: mixing a polymer combination and / or an auxiliary agent to obtain a base material; 2) a metal growth stage: performing pretreatment on the surface of the base material obtained in the step 1), and then growing metal in pores of the base material through chemical plating or water electroplating to obtain a polymer base material; (3) a base material dissolving stage: dissolving the polymer base material deposited with the metal obtained in the step (2) to obtain foam metal without the polymer base material; and 4) a post-treatment stage: carrying out anti-oxidation and drying treatment on the foam metal without the polymer base material obtained in the step 3) to obtain the foam metal. According to the preparation method, the high-porosity polymer base material is introduced, so that the metal uniformly grows in pores in the high-porosity polymer base material, and finally, the polymer base material is completely removed to obtain the foam metal.

Description

Technical Field

[0001] This invention relates to the fields of materials science and engineering, and in particular to a foam metal grown on a polymer substrate and its preparation method. Background Technology

[0002] Foamed metal materials are porous metallic materials that form numerous three-dimensional spatial network structures within a metal matrix. Also known as porous foamed metals, they have broad application prospects in catalysis, aerospace, automotive, energy absorption, and structural lightweighting due to their low density, porosity, lightweight nature, excellent vibration damping properties, and good energy absorption characteristics. Foamed metals are structural and functional materials that integrate structure and function. Currently, aluminum and aluminum alloy foamed metals are the main types, with other foamed metals including magnesium, copper, titanium, lead, zinc, nickel, and steel. The porosity of foamed metals typically ranges from 40% to 99.9%, depending on the type of material and the preparation method; most foamed metals have a porosity exceeding 90%.

[0003] Commonly used methods for preparing foamed metals include casting, deposition, and powder metallurgy. Among them, (1) casting is further divided into foaming method: adding foaming agent (TiH2, ZrH2, CaCO3) to molten metal; percolation casting method: pre-made block particles: NaCl, KCl particles, melted and cooled and then washed with water; hollow ball material method: preparing high melting point heat-resistant alloy foam; investment casting method: heating and volatilizing sponge-like foam plastic to form pores; (2) deposition method is further divided into electrodeposition method: organic polymer foam conductive coating treatment, electroplating, taking out polymer foam, sintering to obtain through-hole metal foam; gas phase Deposition method: porous polyurethane foam is used as a precursor material to deposit metal in a vacuum or isolated atmosphere; (3) Powder metallurgy is further divided into powder foaming method: molding and foaming process (mixing metal powder with metal hydride); slurry method: metal powder, foaming agent and organic carrier form a suspension, which is placed in a mold and heated; loose powder sintering method: fine particles are bonded together by surface tension at high temperature to form porous materials; slurry sponge sintering method: slurry containing metal powder permeates the sponge organic matter, and is sintered at high temperature after heating; fiber metallurgy method: metal powder slurry is poured or mechanically made into felt rings to form felt rings, and then sintered.

[0004] Existing preparation methods include steps such as mixing metal powders, adding foaming agents, and high-temperature treatment. However, these methods suffer from problems such as complex processes, high costs, and uneven pore sizes. Furthermore, the complexity of traditional foam metal material preparation processes leads to high costs, and the pore structure of foam metals prepared using existing processes is undesirable and uncontrollable, making it difficult to precisely control the size, shape, and distribution of pores, resulting in unstable product performance. Therefore, foam metals are currently mainly used in key high-end fields such as military and aerospace, including electrochemical catalysis engineering (catalyst carriers), aerospace environmental engineering (sound-absorbing materials, damping materials, electromagnetic wave shielding materials, and filtration and separation materials), etc.

[0005] To overcome the limitations of traditional foam metal, such as high cost and poor uniformity, there is an urgent need for an innovative technology to optimize foam metal and improve its pore uniformity and material stability. Summary of the Invention

[0006] The purpose of this invention is to provide a foamed metal grown on a polymer substrate and its preparation method, which improves the uniformity of the product; the foamed metal has a porosity greater than 70%, a specific surface area of ​​70-300 m² / g, a pore size of 60 nm-6 mm, and a density of 0.1-0.8 g / cm³. 3 It does not oxidize and discolor, effectively reducing costs and offering excellent performance.

[0007] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0008] This invention provides a method for preparing foamed metal grown on a polymer substrate, comprising the following steps:

[0009] 1) Substrate preparation stage: Mix the polymer combination and / or additives to obtain the substrate;

[0010] 2) Metal growth stage: The surface of the substrate obtained in step 1) is pretreated, and then metal is grown in the pores of the substrate by chemical plating or electroplating to obtain a polymer substrate;

[0011] 3) Substrate dissolution stage: Dissolve the polymer substrate with metal deposited in step 2) to obtain foam metal with the polymer substrate removed;

[0012] 4) Post-processing stage: The foam metal obtained in step 3) after removing the polymer substrate is subjected to anti-oxidation and drying treatment to obtain foam metal.

[0013] Preferably, in step 1), the polymer composition and / or additives are mixed evenly by melt extrusion or foaming agent extrusion, and then extruded and stretched to obtain a high-porosity substrate.

[0014] Preferably, the melt extrusion method includes: uniformly mixing a polymer composition and / or additives, and then extruding, continuously or intermittently stretching the mixture to obtain a high-porosity substrate;

[0015] The foaming extrusion method includes: mixing a polymer combination and / or additives with a foaming agent, and then extruding and directly stretching the mixture to obtain a high-porosity substrate.

[0016] Preferably, the preparation method satisfies one or more of the following conditions:

[0017] The polymer composition is a polymer powder;

[0018] The polymer powder comprises one or a mixture of two or more of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyurethane, polystyrene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyphenylene sulfide, polytetrafluoroethylene, and polyimide; preferably, the polymer powder has a viscosity-average molecular weight of 200,000 to 4,000,000 and a melt index of 0.01 to 100 g / 10 min.

[0019] The adjuvants include nucleating agents and / or antioxidants.

[0020] Preferably, the nucleating agent comprises 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol (DMDBS), sodium 2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate, sodium benzoate, aluminum hydroxybis(-tert-butylbenzoate), 1,3:2,4-dibenzyl sorbitol (DBS), 1,3:2,4-di(--methylbenzyl)sorbitol (MDBS), 1,3:2,4-di(--ethylbenzyl)sorbitol (EDBS), and bis(-tert-butylphenyl)phosphate. Sodium, sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, basic aluminum 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, dehydroabsic acid / dehydroabsicate, disodium bicyclo[2.2.1]heptanedicarboxylate, bicyclo[2.2.1]-5-heptene-2,3-dicarboxylate, aromatic amide, rare earth complex, dibenzyl sorbitol, sorbitol, sodium silicate, sodium aluminum silicate, cobalt carbonate, zinc carbonate, silicon dioxide, calcium carbonate, and mica or aluminum oxide, or one or more thereof;

[0021] The antioxidants include pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetra(bis-T-butylhydroxyhydrogenated cinnamic acid) ester, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis(bis-butylhydroxyhydrogenated cinnamic acid) ester, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrogenated cinnamic acid) ester, bis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, and 1,1,3-tris( 2-Methyl-4-hydroxy-5-tert-butylphenyl)butane, BASF compound antioxidants, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenylmethyl)benzene, hindered phenol and organophosphite compound antioxidants, vinyl bis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritol tetra(3-lauryl thiopropionate), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and one or more thiohedged phenolic antioxidants;

[0022] The foaming agent includes one or a mixture of two or more of azodicarbonamide, azoaminobenzene, diethyl azodicarbonate, diisopropyl azodicarbonate, p-toluenesulfonamide, 4,4'-oxobis(benzenesulfonamide) and dicumyl peroxide.

[0023] Preferably, the total amount of the nucleating agent added accounts for 0-5% of the mass of the polymer composition;

[0024] Preferably, the total amount of the antioxidant added accounts for 0-2% of the mass of the polymer composition;

[0025] Preferably, the total amount of the foaming agent added accounts for 4-20% of the mass of the polymer composition.

[0026] Preferably, the working temperature of extrusion molding in step 1) is 160-450℃;

[0027] Preferably, when the extrusion molding is a wet process, the continuous stretching in the melt extrusion method includes: first extracting the extruded casting with dichloromethane, then stretching and heat-setting, and the resulting substrate has a porosity greater than 70%.

[0028] Alternatively, the intermittent stretching method first stretches the extruded casting at a stretching ratio of 1-5 times, then extracts it with dichloromethane, and then stretches and heat-sets it, resulting in a substrate with a porosity greater than 70%.

[0029] When the extrusion molding is a wet process, the solvent of the wet process includes liquid hydrocarbons or high-boiling-point small molecules.

[0030] Preferably, the solvent comprises one or a mixture of two or more of the following: liquid paraffin, mineral oil, polybutene, tributyl citrate, acetylated tributyl citrate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate and methyl salicylate, diphenyl ether and diphenylmethane.

[0031] Preferably, in step 2), a vacuum magnetron sputtering substrate layer or a metal precursor layer is applied to the surface of the substrate, and then a metal layer is deposited by chemical plating or electroplating, so that the metal grows in the pores.

[0032] Preferably, the preparation method further satisfies one or more of the following conditions:

[0033] The number of vacuum magnetron sputtering operations is 1-5.

[0034] The thickness of the substrate layer is 1-40nm;

[0035] The coated metal precursor layer includes a metal-based, metal oxide-based, or carbon-based conductive agent coating.

[0036] The thickness of the precursor layer is 1-40 nm;

[0037] The metal plating layer is achieved by chemical plating or electroplating using a metal salt solution.

[0038] Preferably, the metal system of the metal precursor layer includes one or more of silver powder, copper powder, and nickel powder; the metal oxide system includes one or more of tin oxide, iron oxide, and zinc oxide; and the carbon system includes one or more of nano carbon black, nano graphite, nano graphene, acetylene black, Ketjen black, or carbon nanotubes.

[0039] Preferably, the concentration of the metal salt solution is 100-500 g·L. -1 ;

[0040] Preferably, the metal salt solution includes one or more of aluminum sulfate solution, ferric sulfate solution, copper sulfate solution, magnesium sulfate solution, lead sulfate solution, zinc sulfate solution, tin sulfate solution, titanium sulfate solution, and nickel sulfate.

[0041] Preferably, in step 3), the polymer substrate with deposited metal is removed by dissolving it with a chemical solvent or by high-temperature pyrolysis, followed by evaporation or combustion; wherein the dissolution temperature is 25-140℃; and the sintering temperature of the polymer substrate is 100-800℃.

[0042] Preferably, the solvent for dissolving the polymer substrate includes one or a mixture of two or more of benzene, toluene, xylene, chloroform, chlorobenzene, carbon tetrachloride, and decahydronaphthalene.

[0043] Preferably, the high-temperature pyrolysis includes one or more of a high-temperature oven, a muffle furnace, or a tube furnace.

[0044] Preferably, in step 4), the preparation method further satisfies one or more of the following conditions:

[0045] The antioxidant treatment includes one or more of chemical plating, physical coating, and metal corrosion inhibitor cleaning; preferably, the physical coating includes zinc spraying or heat-treated oxide film protective layer; the metal corrosion prevention cleaning includes one or more of rust prevention cleaning, oil stain cleaning, ultrasonic cleaning, and acid and alkali cleaning.

[0046] The electroless plating layer includes one or more of the following: electroless chromium plating, electroless nickel plating, electroless tin plating, dimethyl borate reduction, and sodium thiosulfate reduction.

[0047] This invention provides a foamed metal prepared by the preparation method described above.

[0048] Furthermore, the present invention adopts the following specific technical solutions:

[0049] In a first aspect, the present invention provides a method for preparing foamed metal grown on a polymer substrate, comprising: (1) a substrate preparation stage: mixing polymer components and / or additives uniformly by melt extrusion or foaming agent extrusion, and extruding and stretching to obtain a high-porosity substrate; (2) a metal growth stage: performing vacuum magnetron sputtering of a substrate layer or coating a metal precursor layer on the surface of the substrate, and then growing the metal in the pores by chemical plating or electroplating, and controlling the electrolyte concentration, current and time to ensure that the metal can be uniformly and stably deposited in the pores; (3) a substrate dissolution stage: dissolving the polymer substrate by chemical solvent or pyrolyzing it at high temperature and evaporating or burning it to completely remove the substrate; (4) a post-treatment stage: performing anti-oxidation and drying treatment to obtain the foamed metal, thus obtaining a low-cost, simple process with a uniform and stable foamed metal structure, achieving the homogenization and stability improvement of the foam structure.

[0050] Secondly, the present invention also provides a foamed metal prepared by the preparation method described above.

[0051] This invention uses melt extrusion or foaming agent extrusion to uniformly mix a polymer composition and / or additives, and then extrudes and stretches it to obtain a high-porosity substrate with high porosity and uniform pore size. The polymer substrate is completely removed by dissolving in a chemical solvent or by high-temperature pyrolysis and evaporation or combustion, thus retaining the foam metal material and improving the processability and stability of the material.

[0052] This invention utilizes vacuum magnetron sputtering of the substrate layer or coating of a metal precursor layer, chemical plating, or electroplating to easily control and regulate metal growth. It effectively controls and regulates indicators such as porosity, pore size, and density of the foamed metal, resulting in performance advantages such as higher porosity and lower density.

[0053] The present invention produces foamed metal with uniform structure, excellent strength and lightweight properties by growing metal on it, and it is also low in cost and simple in process.

[0054] Compared with the prior art, the present invention has the following technical effects:

[0055] 1) This invention introduces a high-porosity polymer substrate, thereby enabling metal to grow uniformly in its internal pores, and finally completely removes the polymer substrate to obtain foamed metal.

[0056] 2) This invention simplifies the preparation process and reduces manufacturing costs; it improves the uniformity of pores and the stability of the material; and it allows for customized material design based on specific application needs. The foamed metal prepared using the above methods has broad application prospects in lightweight structural materials, thermal insulation materials, and energy-absorbing materials. Its high porosity combined with the physical properties of metals enables it to play an important role in aerospace, automotive industry, and building materials. Attached Figure Description

[0057] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0058] Figure 1 This is a schematic diagram of the structure of the foam metal of the present invention. Detailed Implementation

[0059] As used in this article:

[0060] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0061] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0062] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0063] In these embodiments, unless otherwise specified, all parts and percentages are by weight. Raw material ratios not specified in this invention are for mixing in any proportion.

[0064] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0065] The dry and wet processes described are mature processes in the prior art. Except for the process flow and parameters specifically proposed in this invention, they are basically the same as those in the prior art.

[0066] This invention provides a method for preparing foamed metal grown on a polymer substrate: A polymer combination and / or additives are uniformly mixed using melt extrusion or foaming agent extrusion, and then extruded and stretched to obtain a high-porosity substrate. A vacuum magnetron sputtering base layer or a metal precursor layer is deposited on the surface of the substrate. Then, metal is grown within the pores through chemical plating or electroplating. The concentration, current, and time of the electrolyte are adjusted to ensure uniform and stable deposition of the metal within the pores. The substrate is then completely removed by chemical solvent dissolution or high-temperature pyrolysis followed by evaporation or combustion. Finally, an anti-oxidation treatment is performed to obtain the final product, which is then dried and stored.

[0067] Preferably, the vacuum magnetron sputtering equipment uses PVD (physical vapor deposition) to apply a vacuum nanoscale coating to a substrate using 99% pure copper as the target material. The metal target is bombarded with one or more sputtering processes, causing it to grow inside / on the surface of the substrate pores. Then, the metal is grown inside the pores by chemical plating or electroplating. The concentration of the electrolyte, the current, and the time are adjusted to ensure that the metal can be deposited uniformly and stably inside the pores.

[0068] In some alternative embodiments, the polymer composition is a polymer powder.

[0069] Furthermore, the polymer powder may include one or a mixture of two or more of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyurethane, polystyrene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyphenylene sulfide, and polytetrafluoroethylene or polyimide.

[0070] Furthermore, the foaming agent includes one or a mixture of two or more of the following: azodicarbonamide, azoaminobenzene, diethyl azodicarbonate, diisopropyl azodicarbonate, p-toluenesulfonamide, 4,4'-oxobis(benzenesulfonamide), dicumyl peroxide, etc.

[0071] Further, the adjuvant may include a nucleating agent and / or an antioxidant. Optionally, the nucleating agent includes 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol (DMDBS), sodium 2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate, sodium benzoate, aluminum hydroxybis(-tert-butylbenzoate), 1,3:2,4-dibenzyl sorbitol (DBS), 1,3:2,4-di(--methylbenzyl)sorbitol (MDBS), 1,3:2,4-di(--ethylbenzyl)sorbitol (EDBS), and sodium bis(-tert-butylphenyl)phosphate. Sodium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, basic aluminum 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, dehydroabietic acid / dehydroabirate, disodium bicyclo[2.2.1]heptanedicarboxylate, bicyclo[2.2.1]-5-heptene-2,3-dicarboxylate, aromatic amide, rare earth complex, dibenzyl sorbitol, sorbitol, sodium silicate, sodium aluminum silicate, cobalt carbonate, zinc carbonate, silicon dioxide, calcium carbonate, mica, and aluminum oxide, or two or more of these.

[0072] Further, the antioxidants include pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], pentaerythritol tetrakis(bis-T-butylhydroxyhydrogenated cinnamic acid) ester, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis(bis-butylhydroxyhydrogenated cinnamic acid) ester, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyhydrogenated cinnamic acid) ester, bis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butylphenyl) phosphite, 1,1,3- Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, BASF compound antioxidants, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxyphenylmethyl)benzene, hindered phenol and organophosphite compound antioxidants, vinyl bis(oxyvinyl)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritol tetra(3-lauryl thiopropionate), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester and one or more of thiohedged phenolic antioxidants;

[0073] In some preferred embodiments, the total amount of the nucleating agent added accounts for 0-5% of the mass of the polymer composition.

[0074] In some preferred embodiments, the total amount of the antioxidant added accounts for 0-2% of the mass of the polymer composition.

[0075] In some preferred embodiments, the total amount of the foaming agent added accounts for 4-20% of the mass of the polymer composition.

[0076] In embodiments of the present invention, when the polymer powder and additives are combined, the method for preparing the foam metal is to first blend the solvent and additives of the wet process, then add polymer powder to the first blend to form a uniform secondary mixture, extrude it through a twin-screw extruder to obtain a gel material, and stretch it into a high-porosity substrate using a stretching machine.

[0077] The nucleating agent, antioxidant, and foaming agent are all commercially available products and do not require special preparation methods.

[0078] Furthermore, in some preferred embodiments, the polymer powder used has a viscosity-average molecular weight of 200,000 to 4,000,000 and a melt index of 0.01 to 100 g / 10 min.

[0079] Furthermore, in some preferred embodiments, the working temperature of the polymer combination extrusion molding is 160-450°C.

[0080] In some alternative embodiments, the number of vacuum magnetron sputtering operations is 1-5.

[0081] In some preferred embodiments, the thickness of the substrate is 1-40 nm.

[0082] In some preferred embodiments, the coated metal precursor layer includes a metal-based, metal oxide-based, or carbon-based conductive agent coating.

[0083] In some preferred embodiments, the thickness of the precursor layer is 1-40 nm;

[0084] In some alternative embodiments, the metal plating layer is chemically plated or electroplated using a metal sulfate solution.

[0085] In some preferred embodiments, the metal system of the coated metal precursor layer includes one or more of silver powder, copper powder, and nickel powder; the metal oxide system includes one or more of tin oxide, iron oxide, and zinc oxide; and the carbon system includes one or more of nano-carbon black, nano-graphite, nano-graphene, acetylene black, Ketjen black, or carbon nanotubes.

[0086] In some preferred embodiments, the concentration of the metal sulfate solution is 100-500 g·L. -1 The metal plating time is 10-30 minutes, the temperature is 40-50℃, and the current density is 0.1-0.2 A / cm². 2 .

[0087] Furthermore, the metal includes one or more of aluminum, iron, copper, magnesium, lead, zinc, tin, titanium, nickel, and their alloys;

[0088] In some preferred embodiments, the metal salt solution includes one or more of the following: aluminum sulfate solution, ferric sulfate solution, copper sulfate solution, magnesium sulfate solution, lead sulfate solution, zinc sulfate solution, tin sulfate solution, titanium sulfate solution, and nickel sulfate.

[0089] Furthermore, the solvent for dissolving the polymer substrate preferably includes one or a mixture of two or more of benzene, toluene, xylene, chloroform, chlorobenzene, carbon tetrachloride, and decahydronaphthalene.

[0090] In some preferred embodiments, the dissolution temperature is between 25 and 140°C.

[0091] Furthermore, the high-temperature pyrolysis can be selected from one or more of a high-temperature oven, a muffle furnace, or a tube furnace;

[0092] In some preferred embodiments, the sintering temperature of the polymer substrate is between 100 and 800°C.

[0093] In some preferred embodiments, after the substrate is completely removed by dissolving it in a chemical solvent or by high-temperature pyrolysis and evaporation or combustion, the resulting foamed metal without the polymer substrate can be subjected to a concentration of 80-180 g·L⁻¹. -1 Electroplating with copper sulfate solution for 5-20 minutes at 40-50℃ and a current density of 0.05-0.1 A / cm² 2 The process allows the network structure to grow further, resulting in a structurally stable foam metal, which is then chemically tin-plated and dried.

[0094] Furthermore, the antioxidant treatment includes one or more of chemical plating, physical coating, and metal corrosion inhibitor cleaning.

[0095] In some preferred embodiments, the chemical plating layer includes one or more of the following: chemical chromium plating, chemical nickel plating, chemical tin plating, dimethyl borate reduction, and sodium thiosulfate reduction.

[0096] In some preferred embodiments, the physical coating includes a zinc spray coating or a heat-treated oxide film protective layer.

[0097] In some preferred embodiments, the metal anti-corrosion cleaning includes one or more of the following: rust prevention cleaning, oil stain cleaning, ultrasonic cleaning, and acid and alkali cleaning. Any commercially available cleaning agent can be selected.

[0098] Furthermore, when the extrusion molding is a dry / wet process, the preparation apparatus includes a screw extrusion system, a chilling roller system, a longitudinal stretching system, a primary transverse stretching system, a bi-stretching system, an extraction and drying system, a secondary transverse stretching and retraction system, and a winding and slitting system.

[0099] As an optional embodiment, the stretching includes: first extracting the extruded casting with dichloromethane, then stretching and heat-setting the resulting substrate with a porosity greater than 70%, i.e., a high-porosity, breathable substrate.

[0100] Alternatively, as another optional embodiment, the stretching includes: first stretching the extruded casting at a stretching ratio of 1-5 times, then extracting it with dichloromethane, and then stretching and heat-setting it to obtain a substrate with a porosity greater than 70%, i.e., a high-porosity breathable substrate.

[0101] When the extrusion molding is a dry process, the dry process requires the addition of a foaming agent for foaming extrusion.

[0102] When the extrusion molding is a wet process, the solvent of the wet process includes one or more of liquid hydrocarbons or small molecule substances, such as liquid paraffin, mineral oil, polybutene, tributyl citrate, acetylated tributyl citrate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, or methyl salicylate.

[0103] See Figure 1 This invention also provides a foamed metal prepared by the aforementioned method, wherein the foamed metal has a porosity greater than 70%, a pore size of 60 nm-6 mm, and a density of 0.1-0.8 g / cm³. 3 It exhibits no oxidation or discoloration, effectively reducing costs and offering excellent performance. The foamed metal can be widely used in catalysis, aerospace, automotive, energy absorption, and lightweight structural applications.

[0104] Example 1

[0105] A method for preparing foamed metal grown on a polymer substrate:

[0106] (1) The ingredients are selected as follows: 24 parts by weight of polyethylene powder with a viscosity-average molecular weight of 1 million and 76 parts by weight of liquid paraffin. The polyethylene powder and liquid paraffin are stirred for 1 hour to obtain a blend material.

[0107] (2) The blended material is added into a twin-screw extruder, the processing temperature is 200℃, the speed is 120rpm, and the material is cooled by a 20℃ water bath. The gel material is then extruded and cast into sheets and stretched into a high-porosity substrate.

[0108] During the stretching process, the cast sheet is first extracted with dichloromethane, then stretched and heat-set. The resulting substrate has a porosity of 70%.

[0109] (3) The substrate obtained in step (2) is subjected to three vacuum ion sputtering processes to form a 30 nm thick underlayer. The resulting substrate is then subjected to a concentration of 230 g·L⁻¹. -1 Copper sulfate solution electroplating: Copper is electroplated using copper sulfate solution. The substrate is connected to the negative electrode, and the positive electrode is placed in the copper sulfate solution, which will result in a product in which copper grows uniformly within the substrate.

[0110] (4) Dissolve the polymer substrate with carbon tetrachloride to completely dissolve the substrate, obtain foam metal, then chemically tin-plat it, and finally dry it and put it into storage.

[0111] Example 2

[0112] A method for preparing foamed metal grown on a polymer substrate:

[0113] (1) The ingredients are selected as follows: 25 parts by weight of polypropylene powder, 75 parts by weight of liquid paraffin, 1% of nucleating agent DBS (dibenzyl sorbitol) of the total mass of polypropylene powder, 0.4% of bis(3,5-di-tert-butyl-4-hydroxyphenyl) propionate phosphate, and 0.2% of tris(2,4-di-tert-butylphenyl) phosphite.

[0114] Liquid paraffin, nucleating agent and antioxidant are added to the powder mixing tank and stirred evenly. Then polypropylene powder is added and stirred for 1 hour to obtain the blend material.

[0115] (2) The blended material is added into a twin-screw extruder, the processing temperature is 200℃, the speed is 120rpm, and the material is cooled by a 40℃ water bath. The gel material is then extruded and cast into sheets and stretched into a high-porosity substrate.

[0116] During the stretching process, the cast sheet is first extracted with dichloromethane, then stretched and heat-set. The resulting substrate has a porosity of 75%.

[0117] (3) The substrate obtained in step (2) is subjected to three vacuum ion sputtering processes to form a 30 nm thick underlayer. The resulting substrate is then subjected to a concentration of 230 g·L⁻¹. -1 Copper sulfate solution electroplating: Copper is electroplated using copper sulfate solution. The substrate is connected to the negative electrode, and the positive electrode is placed in the copper sulfate solution, which will result in a product in which copper grows uniformly within the substrate.

[0118] (4) Dissolve the polymer substrate with carbon tetrachloride to completely dissolve the substrate, obtain foam metal, then chemically tin-plat it, and finally dry it and put it into storage.

[0119] Example 3

[0120] A method for preparing foamed metal grown on a polymer substrate:

[0121] (1) The ingredients are selected as follows: 24 parts by weight of polyethylene powder, 76 parts by weight of liquid paraffin, and 4% by weight of foaming agent azodicarbonamide in polyethylene powder. The polyethylene powder, liquid paraffin and azodicarbonamide are stirred for 1 hour to obtain a blend material.

[0122] (2) The blended material is added to a twin-screw extruder at a processing temperature of 200℃ and a rotation speed of 120 rpm. After cooling in a 20℃ water bath, the gel material is extruded and cast into sheets, which are then directly stretched into a high-porosity substrate. The porosity of the resulting substrate is 85%.

[0123] (3) The substrate obtained in step (2) is subjected to two vacuum ion sputtering processes to form a 20 nm thick underlayer. The resulting substrate is then subjected to a concentration of 230 g·L⁻¹. -1Copper sulfate solution electroplating: Copper is electroplated using copper sulfate solution. The substrate is connected to the negative electrode, and the positive electrode is placed in the copper sulfate solution, which will result in a product in which copper grows uniformly within the substrate.

[0124] (4) Dissolve the polymer substrate with carbon tetrachloride to completely dissolve the substrate, obtain foam metal, then chemically tin-plat it, and finally dry it and put it into storage.

[0125] Example 4

[0126] A method for preparing foamed metal grown on a polymer substrate:

[0127] The difference from Example 1 is that in step (1), the extruded casting is first stretched by a stretching factor of 4, then extracted with dichloromethane, and then subjected to conventional stretching and heat setting. The porosity of the resulting substrate is 92%.

[0128] Example 5

[0129] A method for preparing foamed metal grown on a polymer substrate:

[0130] The difference from Example 3 is that in step (2), 100 parts by weight of polyethylene powder and 10% by weight of azodicarbonamide, a foaming agent, are selected. The polyethylene powder and azodicarbonamide are stirred for 1 hour to obtain a blended material. The porosity of the resulting substrate is 90%.

[0131] Example 6

[0132] A method for preparing foamed metal grown on a polymer substrate:

[0133] The difference from Example 1 is that in step (3), the substrate obtained in step (2) is coated with a precursor layer of 30 nm thickness, and the resulting substrate is subjected to a process with a concentration of 230 g·L⁻¹. -1 Copper sulfate solution electroplating: Copper is electroplated using copper sulfate solution. The substrate is connected to the negative electrode, and the positive electrode is placed in the copper sulfate solution, which will result in a product in which copper grows uniformly within the substrate.

[0134] Example 7

[0135] A method for preparing foamed metal grown on a polymer substrate:

[0136] The difference from Example 1 is that in step (3), the substrate obtained in step (2) is subjected to three vacuum ion sputtering processes to form a 30 nm thick underlayer, and the resulting substrate is subjected to a concentration of 230 g·L⁻¹. -1 Ferric sulfate solution electroplating: Iron is electroplated using ferric sulfate solution. The substrate is connected to the negative electrode, and the positive electrode is placed in the ferric sulfate solution, which will result in a product in which iron grows uniformly within the substrate.

[0137] Example 8

[0138] A method for preparing foamed metal grown on a polymer substrate:

[0139] The difference from Example 1 is that in step (4), after the polymer substrate is completely dissolved by carbon tetrachloride, the resulting foam metal without the polymer substrate is subjected again to a concentration of 180 g·L⁻¹. -1 Electroplating of copper sulfate solution in water for 15 minutes: at 45℃ and a current density of 0.05 A / dm³. 2 The process allows the network structure to grow further, resulting in a structurally stable foam metal, which is then chemically tin-plated, dried, and stored.

[0140] Comparative Example 1

[0141] A method for preparing foamed metal grown on a polymer substrate differs from Example 1 in that, in step (2), the casting is first stretched 6.5 times and heat-set during the stretching process, then extracted with dichloromethane, and then stretched and heat-set again. The porosity of the resulting substrate is 46%.

[0142] Comparative Example 2

[0143] A method for preparing foamed metal grown on a polymer substrate, differing from Example 3 in that the foaming agent, azodicarbonamide, is added at 2% of the polyethylene powder. The resulting substrate has a porosity of 60%.

[0144] Comparative Example 3

[0145] A method for preparing foam metal grown on a polymer substrate, which differs from Example 1 in that the foam metal is not chemically tin-plated.

[0146] Table 1 Comparison of product indicators between the examples and the comparative examples.

[0147]

[0148] The product performance in Examples 1-8 and Comparative Examples 1-3 differs significantly. Comparing the foam metal test results in Table 1, the main differences lie in density, porosity, average pore size, and tensile strength. The density of the foam metal is related to its porosity; the higher the porosity, the lower the density. The change in the porosity of the foam metal is mainly related to the porosity of the substrate. The porosity of the foam metal decreases as the porosity of the substrate increases, primarily because copper grows within the pores of the substrate. Larger substrate pores result in a more complex and abundant foam metal network structure, leading to a certain degree of reduction in porosity. In Examples 1-8... The greater the porosity of the foam metal, the smaller the average pore size. Compared with Comparative Examples 1-2, when the porosity of the substrate is below 70%, the metal cannot grow normally in the pores of the substrate, the metal network structure breaks, the structural stability of the foam metal is poor, and thus the tensile strength of the foam metal is low and the average pore size is large. In Example 8, a metal structure stabilization stage is added: that is, the foam metal obtained after removing the polymer substrate is further grown by chemical plating or electroplating, which can connect most of the unconnected branches, making the structure more stable, and its tensile strength is significantly increased compared with Example 1. The porosity of the substrate is mainly related to the solid content of the polymer, the foaming effect of the foaming agent, the stretching method, and the stretching ratio. In the melt extrusion method, the solid content is low, and the porosity increases after the white oil is extracted with dichloromethane. In the foaming agent method, the amount of foaming agent added is large, which increases the porosity. The stretching methods of continuous and discontinuous methods utilize density differences and stress concentration at defect points, the existence of intermolecular topological structures, and the refinement and recrystallization of fibrous crystal structures to obtain a more uniform and fine microporous structure, which increases the porosity. Increasing the stretching ratio of the substrate also increases the porosity. By changing the porosity of the substrate in these ways, the performance indicators of the foamed metal can be improved.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. In addition, those skilled in the art can understand that although some embodiments here include certain features included in other embodiments but not other features, the combination of features of different embodiments means that they are within the scope of the present invention and form different embodiments. For example, in the above claims, any one of the claimed embodiments can be used in any combination. The information disclosed in this background section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form implying that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing a foamed metal grown on a polymer substrate, comprising the following steps: 1) a substrate preparation stage: mixing a polymer combination and / or an additive to obtain a substrate; 2) a metal growth stage: performing a pretreatment on the surface of the substrate obtained in step 1), and then growing a metal in the pores of the substrate by electroless plating or electroplating to obtain a polymer substrate; 3) a substrate dissolution stage: dissolving the polymer substrate with the metal deposited thereon obtained in step 2) to obtain a foamed metal with the polymer substrate removed; 4) a post-treatment stage: performing an anti-oxidation and drying treatment on the foamed metal with the polymer substrate removed obtained in step 3) to obtain a foamed metal.

2. The production method according to claim 1, characterized by, In step 1), the polymer combination and / or the additive are uniformly mixed by a melt extrusion method or a foaming agent foaming extrusion method, and a high-porosity substrate is obtained by extrusion molding and stretching; Preferably, the melt extrusion method comprises uniformly mixing the polymer combination and / or the additive, and a high-porosity substrate is obtained by extrusion molding and continuous or intermittent stretching; The foaming agent foaming extrusion method comprises uniformly mixing the polymer combination, and / or the additive, and a foaming agent, and a high-porosity substrate is obtained by extrusion molding and direct stretching.

3. The preparation method according to claim 2, characterized in that, The preparation method satisfies one or more of the following conditions: The polymer combination is a polymer powder; The polymer powder comprises one or more than two kinds of a mixture of polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyurethane, polystyrene, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polyphenylene sulfide, polytetrafluoroethylene, and polyimide; preferably, the polymer powder has a viscosity-average molecular weight of 2-4 million and a melt index of 0.01-100 g / 10 min; The additive comprises a nucleating agent and / or an antioxidant.

4. The preparation method according to claim 3, characterized in that, The nucleating agent comprises one or more than two kinds of 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol, 2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate sodium, sodium benzoate, aluminum hydroxybis-p-tert-butylbenzoate, 1,3:2,4-dibenzylidene sorbitol, 1,3:2,4-bis(p-methylbenzylidene)sorbitol, 1,3:2,4-bis(p-ethylbenzylidene)sorbitol, bis(p-tert-butylphenyl)phosphate sodium, 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate sodium, 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate aluminum basic salt, dehydroabietic acid / dehydroabietate, disodium bicyclo[2.2.1]heptane dicarboxylate, bicyclo[2.2.1]-5-heptene-2,3-dicarboxylate salt, aromatic amide, rare earth complex, dibenzylidene sorbitol, sorbitol, sodium silicate, sodium aluminum silicate, cobalt carbonate, zinc carbonate, silicon dioxide, calcium carbonate, and mica or alumina. The antioxidant includes one or more of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, pentaerythritol tetra(dibenzyl hydroxyhydrocinnamate), bis(3,5-di-tert-butyl-4-hydroxyphenyl)propionyldiphenyl phosphate, tris(2,4-di-tert-butylphenyl)phosphite, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, BASF complex antioxidant, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, a complex of a hindered phenol and an organic phosphite antioxidant, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritol tetra(3-laurylthiopropionate), n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and a hindered thio-phenolic antioxidant; The foaming agent includes one or more of azodicarbonamide, azoaminobenzene, diethyl azodicarboxylate, diisopropyl azodicarboxylate, p-toluenesulfonylurea, 4,4'-oxybis(benzenesulfonylurea), and a mixture of two or more of dicumyl peroxide; Preferably, the total amount of the nucleating agent added accounts for 0-5% of the mass of the polymer combination; Preferably, the total amount of the antioxidant added accounts for 0-2% of the mass of the polymer combination; Preferably, the total amount of the foaming agent added accounts for 4-20% of the mass of the polymer combination.

5. The preparation method according to claim 2, characterized in that, The working temperature of the extrusion forming in step 1) is 160-450°C; Preferably, when the extrusion forming is a wet process, the continuous method of melt extrusion includes: first extracting the extruded cast piece with dichloromethane, then stretching and heat setting, and the porosity of the obtained substrate is greater than 70%; Or, the discontinuous method of stretching first stretches the extruded cast piece at a stretching ratio of 1-5, then extracts it with dichloromethane, and then stretches and heat sets, and the porosity of the obtained substrate is greater than 70%; When the extrusion forming is a wet process, the solvent of the wet process includes a liquid hydrocarbon or a high-boiling small molecule substance; Preferably, the solvent includes one or more of a mixture of liquid paraffin, mineral oil, polybutene, tributyl citrate, acetyl tributyl citrate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and methyl salicylate, diphenyl ether, and diphenylmethane.

6. The method of claim 1, wherein, In step 2), the surface of the substrate is vacuum magnetron sputtered with a primer layer or coated with a metal precursor layer, and then a metal layer is plated by electroless plating or electroplating, so that the metal grows in the pores.

7. The preparation method according to claim 6, characterized in that, The preparation method further satisfies one or more of the following conditions: The number of vacuum magnetron sputtering is 1-5 times; The thickness of the primer layer is 1-40 nm; The coated metal precursor layer includes a metal-based, metal oxide-based, or carbon-based conductive agent coating; The antioxidant includes one or more of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, pentaerythritol tetra(dibenzyl hydroxyhydrocinnamate), bis(3,5-di-tert-butyl-4-hydroxyphenyl)propionyldiphenyl phosphate, tris(2,4-di-tert-butylphenyl)phosphite, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, BASF complex antioxidant, 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, a complex of a hindered phenol and an organic phosphite antioxidant, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], pentaerythritol tetra(3-laurylthiopropionate), n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and a hindered thio-phenolic antioxidant; The foaming agent includes one or more of azodicarbonamide, azoaminobenzene, diethyl azodicarboxylate, diisopropyl azodicarboxylate, p-toluenesulfonylurea, 4,4'-oxybis(benzenesulfonylurea), and a mixture of two or more of dicumyl peroxide; Preferably, the total amount of the nucleating agent added accounts for 0-5% of the mass of the polymer combination; Preferably, the total amount of the antioxidant added accounts for 0-2% of the mass of the polymer combination; Preferably, the total amount of the foaming agent added accounts for 4-20% of the mass of the polymer combination. The working temperature of the extrusion forming in step 1) is 160-450°C; Preferably, when the extrusion forming is a wet process, the continuous method of melt extrusion includes: first extracting the extruded cast piece with dichloromethane, then stretching and heat setting, and the porosity of the obtained substrate is greater than 70%; Or, the discontinuous method of stretching first stretches the extruded cast piece at a stretching ratio of 1-5, then extracts it with dichloromethane, and then stretches and heat sets, and the porosity of the obtained substrate is greater than 70%; When the extrusion forming is a wet process, the solvent of the wet process includes a liquid hydrocarbon or a high-boiling small molecule substance; Preferably, the solvent includes one or more of a mixture of liquid paraffin, mineral oil, polybutene, tributyl citrate, acetyl tributyl citrate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and methyl salicylate, diphenyl ether, and diphenylmethane. In step 2), the surface of the substrate is vacuum magnetron sputtered with a primer layer or coated with a metal precursor layer, and then a metal layer is plated by electroless plating or electroplating, so that the metal grows in the pores. The preparation method further satisfies one or more of the following conditions: The number of vacuum magnetron sputtering is 1-5 times; The thickness of the primer layer is 1-40 nm; The coated metal precursor layer includes a metal-based, metal oxide-based, or carbon-based conductive agent coating; The thickness of the precursor layer is 1-40 nm; The metal plating layer is prepared by electroless plating or electroplating using a metal salt solution; Preferably, the metal of the metal precursor layer includes one or more of silver powder, copper powder, and nickel powder, the metal oxide includes one or more of tin oxide, iron oxide, and zinc oxide, and the carbon includes one or more of nano-carbon black, nano-graphite, nano-graphene, acetylene black, Ketjen black, and carbon nanotube. Preferably, the concentration of the metal salt solution is 100-500 g L -1 ; Preferably, the metal salt solution includes one or more of aluminum sulfate solution, iron sulfate solution, copper sulfate solution, magnesium sulfate solution, lead sulfate solution, zinc sulfate solution, tin sulfate solution, titanium sulfate solution, and nickel sulfate solution.

8. The method of claim 1, wherein, In step 3), the polymer substrate with the deposited metal is removed by chemical solvent dissolution or high-temperature pyrolysis, and evaporation or combustion; the dissolution temperature is 25-140°C, and the sintering temperature of the polymer substrate is 100-800°C. The solvent for dissolving the polymer substrate preferably includes one or more of benzene, toluene, xylene, chloroform, chlorobenzene, carbon tetrachloride, and decaline. Preferably, the high-temperature pyrolysis includes one or more of a high-temperature oven, a muffle furnace, or a tube furnace.

9. The method of claim 1, wherein, In step 4), the preparation method further satisfies one or more of the following conditions: The anti-oxidation treatment includes one or more of chemical plating, physical coating, and metal corrosion inhibitor cleaning; the physical coating preferably includes a zinc spray coating or a heat-treated oxide film protective layer; the metal corrosion inhibitor cleaning includes one or more of rust-proof cleaning, oil cleaning, ultrasonic cleaning, and acid-base cleaning. The chemical plating layer includes one or more of chemical plating of chromium, nickel, and tin, dimethyl boron alkali solution reduction, and sodium thiosulfate reduction.

10. A foamed metal prepared by the preparation method of any one of claims 1-9.

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