Composite silver-plated copper foil and preparation method thereof
By photocatalytically depositing silver nanoparticles and alloying, combined with rare earth elements, the problems of signal distortion and reduced adhesion of copper foil in high-frequency environments were solved, achieving high conductivity and peel strength of low-roughness copper foil, which is suitable for the 5G field.
Patent Information
- Application Number
- CN202511139130.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-14
- Publication Date
- 2025-11-25
AI Technical Summary
Existing copper foils suffer from skin effect in high-frequency environments, leading to signal distortion and reduced adhesion between the copper foil and the substrate. Furthermore, traditional processes struggle to simultaneously improve conductivity and peel strength.
Silver nanoparticles were deposited using photocatalytic deposition and then alloyed. Combined with the use of rare earth elements, a dense and uniform silver coating was formed. The adhesion to the copper foil surface was improved by using a silane coupling agent.
It achieves high conductivity and good peel strength in low-roughness copper foil, making it suitable for high-frequency signal transmission, and has excellent corrosion resistance, making it suitable for the 5G field.
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Figure CN121006531A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of copper foil preparation, in particular to a composite silver-plated copper foil and a preparation method thereof. BACKGROUND
[0002] In today's era of rapid development of science and technology, copper foil has become an important basic material indispensable in the manufacture of electronic equipment, known as the "nerve network" of signal and power transmission, communication of electronic products, and is widely used in the manufacture of printed circuit boards and lithium ion batteries. PCB is an important electronic component, also known as printed circuit board or printed circuit board. It makes the circuit miniaturized and visualized, and plays an important role in the batch production of fixed circuits and the optimization of electrical appliance layout.
[0003] High frequency and high speed as a key term of 5G are closely related to the development of the PCB industry, and high-performance copper foil plays a role in connecting circuits and signal transmission in PCB. Due to the existence of skin effect in high-frequency environment, the equivalent resistance of the circuit becomes larger, the energy consumption becomes more, and the higher the frequency, the more obvious the skin effect, and there are problems such as poor anti-peeling strength between copper foil and substrate. In order to weaken the influence of skin effect on the circuit, a high-conductivity material needs to be developed to reduce the overall circuit effective resistance. Currently, the most commonly used copper foil in high-frequency PCB is reverse copper foil (RTF), high-temperature ductility copper foil (HTE), low-profile copper foil (VLP), etc. Except that the surface roughness is different, the conductivity does not change.
[0004] As we all know, the high frequency and high speed of signal transmission make the signal transmission more and more concentrated in the "surface layer" of electrolytic copper foil. If a conventional roughness copper foil is used, the result is that as the signal transmission frequency increases, the signal "distortion" caused by skin effect will become more and more serious. Therefore, there is an urgent need for a low-roughness copper foil production process. However, lower roughness will reduce the bonding force between copper foil and resin substrate, so the technical problem to be solved by the present application is to provide a process method, after the process treatment, the copper foil has lower roughness while retaining good anti-peeling strength and has good corrosion resistance and conductivity. SUMMARY
[0005] In order to solve the above technical problems existing in the prior art, the present application provides a composite silver-plated copper foil and a preparation method thereof.
[0006] The technical solution of the present application to solve the above technical problems is as follows: The first aspect of the present application is to provide a preparation method of a composite silver-plated copper foil, comprising the following steps: Step one: the surface of the copper foil is pretreated by pickling to remove the oxides and impurities on the surface; Step two: the pickled copper foil is roughened and solidified. Step three: photocatalytic deposition method for depositing silver nanoparticles; Step four: alloying treatment; Step five: sequentially performing anti-oxidation treatment, silane coupling agent coating treatment, and drying to obtain the composite silver-plated copper foil.
[0007] On the basis of the above technical solutions, the application can also be improved as follows: Further, in step three, the silver solution used in the photocatalytic deposition method comprises the following components: silver nitrate 3-5 g / L, ethanol 0.2-0.6 g / L, glycerol tristearate 0.2-0.5 g / L, and photocatalyst 0.05-0.1 g / L.
[0008] Further, the photocatalyst is prepared by the following method: (1) preparing a copper diglycinate complex by mixing Cu(NO3)2·3H2O and glycine in distilled water; (2) simultaneously adding the copper diglycinate complex and titanium isopropoxide to a mixed solution of ethanol and water, then refluxing the mixture for at least 48 h to obtain a colloidal solution, and drying and calcining the colloidal solution to obtain the photocatalyst.
[0009] Further, the molar ratio of titanium isopropoxide, ethanol, and water is (1-1.5):(2-3):(8-10); the temperature of the distilled water is 85-90℃; the temperature of the mixed solution of ethanol and water is 65-70℃; and the calcination temperature is 400-500℃ and the calcination time is 4-6 h.
[0010] Further, the photocatalytic deposition method uses a 350-450w Xe lamp, the light power density is 1500-2000 mW / cm 2 , the distance between the Xe lamp and the reactor is 60 mm, and the irradiation time is 1-3 h.
[0011] Further, in step four, the electrolyte used in the alloying treatment is a Ni-Co alloy solution containing rare earth elements, and the rare earth elements are selected from one or more of La, Ce, Pr, and Nd.
[0012] During the alloy deposition process, a rare earth surface treatment agent is added to form a Ni-Co-rare earth element ternary alloy coating, further improving the corrosion resistance of the copper foil surface.
[0013] Further, in step four, the electrolyte comprises: potassium pyrophosphate 120-200 g / L, cobalt sulfate 2-5 g / L, nickel sulfate 5-10 g / L, rare earth elements 10-50 mg / L, sodium chloride 1-2 g / L, and sodium dodecyl sulfate 0.1-0.5 g / L; the process conditions of the alloying treatment are: pH 7-9, temperature 35-45℃, current density 1-3.5 A / dm 2 , and plating time 5-10 s.
[0014] Further, in step five, the anti-oxidation treatment is performed using an anti-oxidation treatment solution, the concentration of hexavalent chromium ions in the anti-oxidation treatment solution is 1.5-3 g / L; the anti-oxidation treatment has a pH value of 12-14, a temperature of 30-36℃, a current density of 4-6 A / dm 2 , and a plating time of 5-10 s; the silane coupling agent coating treatment is performed by spraying a silane coupling agent with a volume concentration of 0.2% on the composite copper foil after the anti-oxidation treatment; the silane coupling agent is selected from one or more of 3-aminopropyl triethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; the drying temperature is 200-250℃, and the drying time is 8-12 s.
[0015] Further, in step two, the roughening treatment is performed by electroplating the copper foil after the pickling in a roughening solution, the roughening solution comprises: a concentration of divalent copper ions of 8-20 g / L and a concentration of sulfuric acid of 150-200 g / L; the roughening treatment has a temperature of 25-30℃, a current density of 8-10 A / dm 2 , and a plating time of 8-12 s; the solidification treatment is performed by electroplating the copper foil after the roughening in a solidification solution, the solidification solution comprises: a concentration of divalent copper ions of 60-80 g / L and a concentration of sulfuric acid of 80-100 g / L; the solidification treatment has a temperature of 40-45℃, a current density of 5-8 A / dm 2 , and a plating time of 6-8 s.
[0016] The roughening and the solidification can be performed by one-step electroplating or multi-step electroplating.
[0017] Further, in step one, the copper foil is subjected to pickling pretreatment using a sulfuric acid solution with a mass fraction of 2-4%; in the present application, the copper foil can be HVLP copper foil or HTE copper foil.
[0018] Another aspect of the present application is to provide a composite silver-plated copper foil prepared by the above method.
[0019] Compared with the prior art, the present application has the following technical effects: (1) The chemical properties of rare earth elements are relatively active, and they have specific adsorption, which can significantly improve the stability of the plating solution and the performance of the plated layer in the traditional electrodeposition process. Therefore, adding trace amounts of rare earth elements during alloy deposition can effectively improve the compactness and uniformity of the plated layer microstructure, improve the corrosion resistance of the plated layer during grain refinement, improve the anti-peeling ability of the plated layer, and improve the performance of the plated layer. Moreover, rare earth ions are easily adsorbed on active sites of crystal growth, thereby slowing down the speed of crystal growth, refining the crystal structure of the plated layer, making the plated layer microstructure compact and uniform, and also improving the electrochemical corrosion resistance; (2) The silver nanoparticles deposited by the photocatalytic method can accelerate the oxidation-reduction reaction with the molecules on the surface of the photocatalyst, and the surface plasmon resonance effect of the silver nanoparticles can also promote the great enhancement in the near-field absorption amplitude, further improving the photocatalytic performance, and the obtained silver plated layer is uniform and delicate and is not easy to fall off; (3) By depositing silver through photocatalysis, a silver layer with a specific micro-morphology and structure can be formed on the surface of the copper foil. The optimization of such micro-morphology and structure not only facilitates the transmission of electrons, but also improves the mechanical properties and stability of the copper foil; (4) The copper foil obtained by the treatment process of the present application can form a uniform and compact plated layer on the surface of the copper foil. The use of the steps of photocatalytic deposition of silver nanoparticles and alloying treatment improves the conductivity and corrosion resistance of the copper foil, and meets the requirements of low roughness and high peeling strength of the copper foil. When used for PCB, it can better meet the characteristics of high-frequency signal transmission and low loss in the 5G field; (5) Ag is one of the metals with the best electrical conductivity, with an electrical conductivity of 6.30 x 10 7 S / m. In addition, Ag also has excellent mechanical properties, thermal conductivity, optical properties, etc., making it a perfect reinforcing phase for metal matrix composites. Therefore, introducing Ag during the surface treatment stage to improve the thermal, electrical and mechanical properties of the copper foil has good development prospects and is expected to be used in the fields of communication, semiconductors and aerospace, promoting the development of related industries. BRIEF DESCRIPTION OF DRAWINGS
[0020] Figure 1 The electron microscope photograph of the silver nanoparticles prepared in Example 1 of the present application. DETAILED DESCRIPTION
[0021] The advantages and effects of the present application can be easily understood by those skilled in the art from the content disclosed in the specification. Although the description of the present application will be introduced in combination with the preferred embodiments, it does not mean that the features of the present application are limited to the embodiments. On the contrary, the purpose of introducing the present application in combination with the embodiments is to cover other options or modifications which can be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0022] In the embodiments and comparative examples of the present application, 35 μm HVLP hair foil is selected.
[0023] Example 1 A preparation method of a composite silver-plated copper foil, comprising the following steps: (1) Copper foil pretreatment: take 35 μm HVLP hair foil, and perform pickling with a mass fraction of 2% sulfuric acid solution.
[0024] (2) Roughening treatment: perform electroplating of the pickled copper foil in a roughening solution, and the composition of the roughening solution is: the concentration of divalent copper ions is 15 g / L, and the concentration of sulfuric acid is 150 g / L; the temperature of the roughening treatment is 25 ℃, the current density is 8 A / dm 2 , and the electroplating time is 8 s.
[0025] (3) Solidification treatment: perform electroplating of the roughened copper foil in a solidification solution, and the composition of the solidification solution is: the concentration of divalent copper ions is 60 g / L, and the concentration of sulfuric acid is 80 g / L; the temperature of the solidification treatment is 40 ℃, the current density is 5 A / dm 2 , and the electroplating time is 6 s.
[0026] (4) Photocatalytic deposition of silver nanoparticles: place the solidified copper foil in a silver nitrate solution containing a photocatalyst for photocatalytic deposition, and the composition of the solution is: silver nitrate 3 g / L, ethanol 0.2 g / L, glycerol tristearate 0.2 g / L, and photocatalyst 0.05 g / L.
[0027] The photocatalyst is obtained by the following method: firstly, a copper diglycinate complex is prepared by mixing Cu(N03)2-3H20 and glycine in a molar ratio of 1:2 in distilled water at 85°C; then, 25 mL of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into an ethanol-water solution at 65°C, the molar ratio of titanium (IV) isopropoxide: ethanol: water being 1:2.5:8; the mixture is then refluxed for 48 h to obtain a colloidal solution, which is then dried in air at 70°C for 12 h, and the obtained powder is calcined in air at 400°C for 6 h to obtain the photocatalyst.
[0028] The process conditions for photocatalytic deposition of silver are as follows: a 350 w Xe lamp (light power density is 1500 mW / cm 2 ), the distance between the Xe ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 1 h.
[0029] (5) Alloying treatment: an alloy layer is deposited by using a Ni-Co plating solution containing nickel sulfate 5 g / L, cobalt sulfate 2 g / L, cerium sulfate 10 mg / L, potassium pyrophosphate 160 g / L, sodium chloride 1 g / L, and sodium dodecyl sulfate 0.1 g / L; the process conditions for alloying treatment are as follows: the temperature of the plating solution is 42°C, the pH value is 8.0, the current density is 2 A / dm 2 , and the plating time is 8 s.
[0030] (6) Anti-oxidation treatment: the copper foil after alloying treatment is subjected to anti-oxidation treatment, the composition of the anti-oxidation treatment solution is as follows: the concentration of hexavalent chromium ions is 1.5 g / L; the pH value of the anti-oxidation treatment is 12, the temperature is 30°C, the current density is 4 A / dm 2 , and the plating time is 5 s.
[0031] (7) Silane coupling agent coating treatment: the copper foil after anti-oxidation treatment is washed with water and then sprayed with a 3-aminopropyl triethoxysilane aqueous solution with a volume concentration of 0.2%.
[0032] (8) Drying: the treated copper foil is dried at a temperature of 200°C for 8 s to obtain a finished composite silver-plated copper foil.
[0033] Example 2 The treatment process of Example 2 is different from that of Example 1 in that silver nanoparticles are photocatalytically deposited: the solidified copper foil is placed in a silver nitrate solution containing a photocatalyst for photocatalytic deposition; the composition of the solution is as follows: silver nitrate 4 g / L, ethanol 0.4 g / L, glyceryl tristearate 0.3 g / L, and photocatalyst 0.08 g / L.
[0034] The photocatalyst is prepared by the following method: firstly, Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 are mixed in distilled water at 90°C to prepare a copper diglycinate complex; then, 30 mL of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into an ethanol-water solution at 68°C, the molar ratio of titanium (IV) isopropoxide, ethanol and water being 1.2:2:9; the mixture is then refluxed for 50 h to obtain a colloidal solution, which is then dried in air at 70°C for 12 h, and the obtained powder is calcined in air at 450°C for 5 h to obtain the photocatalyst.
[0035] The process conditions for photocatalytic deposition of silver are as follows: a 450 w Xe lamp (light power density 2000 mW / cm2) is used, the distance between the Xe ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 2 h.
[0036] After silver plating, alloying treatment is performed, and the electrolyte used comprises: nickel sulfate 8 g / L, cobalt sulfate 3 g / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 180 g / L, sodium chloride 1.5 g / L, and sodium dodecyl sulfate 0.2 g / L; the plating solution temperature is 40°C, the pH value is 8.0, the current density is 1.5 A / dm2, and the electroplating time is 10 s. 2
[0037] The rest of the process is the same as in Example 1, which will not be repeated here.
[0038] Example 3 Example 3 differs from Example 1 in that silver nanoparticles are photocatalytically deposited: the copper foil after solidification treatment is placed in a silver nitrate solution containing a photocatalyst for photocatalytic deposition; the composition of the solution is: silver nitrate 5 g / L, ethanol 0.6 g / L, glycerol tristearate 0.5 g / L, and photocatalyst 0.1 g / L.
[0039] The photocatalyst is prepared by the following method: firstly, Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 are mixed in distilled water at 90°C to prepare a copper diglycinate complex; then, 35 mL of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into an ethanol-water solution at 65°C, the molar ratio of titanium (IV) isopropoxide, ethanol and water being 1.5:2:10; the mixture is then refluxed for 48 h to obtain a colloidal solution, which is then dried in air at 70°C for 12 h, and the obtained powder is calcined in air at 500°C for 4 h to obtain the photocatalyst.
[0040] The process conditions for photocatalytic deposition of silver are as follows: a 450 w Xe lamp (light power density 2000 mW / cm2) is used, the distance between the Xe ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 3 h.
[0041] After silver plating, alloying treatment is carried out, and the electrolyte comprises: nickel sulfate 10 g / L, cobalt sulfate 5 g / L, cerium sulfate 10 mg / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 180 g / L, sodium chloride 1.5 g / L, and sodium dodecyl sulfate 0.5 g / L; the plating solution temperature is 40°C, the pH value is 9.0, the current density is 3.5 A / dm 2 , and the plating time is 5 s.
[0042] The remaining processes are the same as those in Example 1, which are not described here.
[0043] Comparative Example 1 Photocatalytic deposition of silver nanoparticles: the solidified copper foil is placed in a silver nitrate solution containing a photocatalyst for photocatalytic deposition; the solution composition is: silver nitrate 3 g / L, ethanol 0.2 g / L, glycerol tristearate 0.2 g / L, and photocatalyst 0.06 g / L.
[0044] The photocatalyst is obtained by the following method: first, a copper diglycinate complex is prepared by mixing Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 in 85°C distilled water; then, 25 mL of the above solution and titanium (IV) isopropoxide are simultaneously added to a 70°C ethanol-water solution, and the molar ratio of titanium (IV) isopropoxide, ethanol, and water is 1:2.5:8; then the mixture is refluxed for 48 h to obtain a colloidal solution, which is then dried in air at 70°C for 12 h; the obtained powder is calcined in air at 450°C for 5 h to obtain the photocatalyst.
[0045] The process conditions for photocatalytic deposition are as follows: a 350 w Xe lamp (light power density is 1500 mW / cm²) is used, the distance between the ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 1 h.
[0046] After silver plating, alloying treatment is carried out, and the electrolyte comprises: nickel sulfate 10 g / L, cobalt sulfate 5 g / L, cerium sulfate 10 mg / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 180 g / L, sodium chloride 1.5 g / L, and sodium dodecyl sulfate 0.5 g / L; the plating solution temperature is 40°C, the pH value is 9.0, the current density is 3.5 A / dm 2 , and the plating time is 5 s.
[0047] The remaining processes are the same as those in Example 1, which are not described here.
[0048] Comparative Example 2 Photocatalytic deposition of silver nanoparticles: the solidified copper foil is placed in a solution containing a photocatalyst for photocatalytic deposition; the solution composition is: ethanol 0.2 g / L, glycerol tristearate 0.2 g / L, and photocatalyst 0.08 g / L.
[0049] The photocatalyst is obtained by the following method: firstly, copper diglycinate complex is prepared by mixing Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 in 90 ℃ distilled water; then, 25 mL of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into a 70 ℃ ethanol-water solution, the molar ratio of titanium (IV) isopropoxide, ethanol and water being 1.5:2:10; then the mixture is refluxed for 48 h to obtain a colloidal solution, and finally the mixture is dried in air at 70 ℃ for 12 h; the obtained powder is calcined in air at 450 ℃ for 5 h to obtain the photocatalyst.
[0050] The process conditions for photocatalytic deposition of silver are as follows: a 450 w Xe lamp (light power density is 2000 mW / cm²) is used, the distance between the Xe ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 2 h.
[0051] Then, the alloy layer is treated, and the electrolyte comprises: nickel sulfate 5 g / L, cobalt sulfate 2 g / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 180 g / L, sodium chloride 1.5 g / L, and sodium dodecyl sulfate 0.3 g / L; the temperature of the plating solution is 42 ℃, the pH value is 9.0, the current density is 3.5 A / dm 2 , and the plating time is 5 s.
[0052] The rest of the process is the same as in Example 1, which will not be repeated here.
[0053] Comparative Example 3 Photocatalytic deposition of silver nanoparticles: the copper foil after the solidification treatment is placed in a silver nitrate solution containing a photocatalyst for photocatalytic deposition; the composition of the solution is: silver nitrate 1 g / L, ethanol 0.2 g / L, glycerol tristearate 0.2 g / L and photocatalyst 0.06 g / L.
[0054] The photocatalyst is obtained by the following method: firstly, copper diglycinate complex is prepared by mixing Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 in 90 ℃ distilled water; then, 25 mL of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into a 65 ℃ ethanol-water solution, the molar ratio of titanium (IV) isopropoxide, ethanol and water being 1.2:2.5:9; then the mixture is refluxed for 48 h to obtain a colloidal solution, and then the mixture is dried in air at 70 ℃ for 12 h; the obtained powder is calcined in air at 500 ℃ for 4 h to obtain the photocatalyst.
[0055] The process conditions for photocatalytic deposition of silver are as follows: a 450 w Xe lamp (light power density is 2000 mW / cm²) is used, the distance between the Xe ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 3 h.
[0056] After silver plating, alloying treatment is carried out, and the electrolyte comprises: nickel sulfate 8 g / L, cobalt sulfate 3 g / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 200 g / L, sodium chloride 1 g / L, and sodium dodecyl sulfate 0.3 g / L; the plating solution temperature is 42°C, the pH value is 9.0, the current density is 3.5 A / dm 2 , and the electrodeposition time is 5 s.
[0057] The remaining processes are the same as those in Example 1, which are not described herein.
[0058] Comparative Example 4 Photocatalytic deposition of silver nanoparticles: the solidified copper foil is subjected to photocatalytic deposition in a solution containing a photocatalyst; the solution composition is: silver nitrate 8 g / L, ethanol 0.3 g / L, glycerol tristearate 0.2 g / L, and photocatalyst 0.1 g / L.
[0059] The photocatalyst is obtained by the following method: copper diglycinate complex is prepared by mixing Cu(NO3)2·3H2O and glycine in a molar ratio of 1:2 in 90°C distilled water; then, a proper volume of the above solution and titanium (IV) isopropoxide are simultaneously added dropwise into a 70°C ethanol-water solution, and the molar ratio of titanium (IV) isopropoxide, ethanol, and water is 1:2.5:8; then the mixture is refluxed for 48 h to obtain a colloidal solution, which is then dried in air at 70°C for 12 h; the obtained powder is calcined in air at 400°C for 6 h to obtain the photocatalyst.
[0060] The process conditions for photocatalytic deposition of silver are as follows: a 350 w Xe lamp (light power density is 1500 mW / cm²) is used, the distance between the ultraviolet lamp and the reactor is 60 mm, and the irradiation time is 2 h.
[0061] After silver plating, alloying treatment is carried out, and the electrolyte comprises: nickel sulfate 8 g / L, cobalt sulfate 3 g / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 180 g / L, sodium chloride 1 g / L, and sodium dodecyl sulfate 0.1 g / L; the plating solution temperature is 42°C, the pH value is 9.0, the current density is 2 A / dm 2 , and the electrodeposition time is 5 s.
[0062] The remaining processes are the same as those in Example 1, which are not described herein.
[0063] Comparative Example 5 Photocatalytic deposition of silver nanoparticles: the solidified copper foil is subjected to photocatalytic deposition of silver; the solution composition is: silver nitrate 3 g / L, ethanol 0.2 g / L, and glycerol tristearate 0.2 g / L.
[0064] The process conditions of the photocatalytic deposition are as follows: a 450 w Xe lamp (light power density is 2000 mW / cm²), the distance between the UV lamp and the reactor is 60 mm, and the irradiation time is 3 h.
[0065] After silver plating, alloying treatment is performed, and the electrolyte comprises: nickel sulfate 8 g / L, cobalt sulfate 3 g / L, lanthanum sulfate 10 mg / L, potassium pyrophosphate 160 g / L, sodium chloride 1 g / L, and sodium dodecyl sulfate 0.1 g / L; the plating solution temperature is 42°C, the pH value is 9.0, the current density is 3.5 A / dm 2 , and the electrodeposition time is 5 s.
[0066] The rest of the process is the same as that in Example 1, which is not described here.
[0067] Test The composite silver-plated copper foils obtained in Examples 1-3 and Comparative Examples 1-5 are laminated with FR-4 prepreg, and the surface roughness, peel strength, electrochemical corrosion resistance, and resistance of the composite copper foil are tested, and the results are shown in Table 1.
[0068] The test methods of the above properties are as follows: 1. Surface roughness: The probe-type surface roughness test method specified in JIS B0651-2001 is used, and a German M2 surface roughness tester is used for testing.
[0069] 2. Peel strength: The composite silver-plated copper foil is laminated with FR-4 prepreg, and a copper foil plate is formed by hot pressing in a press, and 3 mm lines are etched on an etching machine, and the test is performed according to the method specified in IPC-TM-650.
[0070] 3. The Tafel curve fitting is used to obtain the self-corrosion current density and self-corrosion potential by using an electrochemical workstation, so as to evaluate the electrochemical corrosion resistance of the coating. The self-corrosion potential reflects the difficulty of alloy corrosion, and the self-corrosion current density reflects the corrosion rate of the alloy. The closer the self-corrosion potential is to 0, the smaller the self-corrosion current density, and the better the electrochemical corrosion resistance of the alloy layer. The electrochemical test uses a three-electrode system, the above-prepared composite silver-plated copper foil is used as the working electrode, a platinum sheet is used as the counter electrode, and a saturated calomel electrode is used as the reference electrode; the corrosion medium is a 3.5% NaCl solution, the three-electrode system is immersed in the corrosion medium, and the polarization curve is measured to obtain the self-corrosion current density and self-corrosion potential data, and the electrochemical corrosion resistance of the composite copper foil surface layer is obtained according to the self-corrosion current density and self-corrosion potential data.
[0071] 4. The composite silver-plated copper foil is tested and the resistance is recorded by using HPS2524 / 2526 precision square resistance tester; the lower the resistance is, the better the conductive performance of the composite silver-plated copper foil is, and the faster the signal transmission is.
[0072] Table 1: Performance test results of the composite silver-plated copper foils obtained in Examples 1-3 and Comparative Examples 1-5
[0073] As can be seen from Table 1, when different rare earth elements are added and the silver content is controlled within an effective range, the composite silver-plated copper foil prepared has a lower roughness, a self-corrosion current density that is one order of magnitude smaller than that of the comparative example, and a lower resistance. Compared with Example 1, Comparative Example 1 does not add rare earth elements, and the self-corrosion potential is significantly negatively shifted, the self-corrosion current density is significantly increased, and the corrosion resistance is poor, indicating that the addition of rare earth metals can significantly improve the electrochemical corrosion resistance of the surface of the composite silver-plated copper foil. In Comparative Example 2, no silver nanoparticles are plated, and the resistance is significantly increased, indicating that the transmission of electrical signals is blocked. In Comparative Example 3, the silver content is low, and the amount of silver nanoparticles deposited by light is small, so the surface is not dense enough, which slows down the signal transmission in some places, and the uneven surface increases the roughness of the composite silver-plated copper foil and also makes the corrosion resistance worse. In Comparative Example 4, high-concentration silver is added, and the peel strength of the composite silver-plated copper foil is poor, because under the same conditions, increasing the silver content does not increase the deposition amount of silver, on the contrary, a large amount of silver nanoparticles will adhere to the copper foil, which poses a risk of powdering, so the deposition amount of silver must be controlled within a certain range. In Comparative Example 5, no photocatalyst is added, and silver cannot be rapidly deposited on the surface of the copper foil in cooperation with the photocatalyst, indicating that the addition of the photocatalyst in the light deposition can more effectively increase the deposition amount of silver, thereby obtaining a composite silver-plated copper foil with a uniform and dense surface.
[0074] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for preparing composite silver-plated copper foil, characterized in that, Includes the following steps: Step 1: The copper foil surface undergoes acid pickling pretreatment; Step 2: The pickled copper foil undergoes roughening and curing treatment; Step 3: Deposit silver nanoparticles using photocatalytic deposition method; Step 4: Alloying treatment; Step 5: Perform anti-oxidation treatment, silane coupling agent coating treatment, and dry to obtain the composite silver-plated copper foil.
2. The method for preparing composite silver-plated copper foil according to claim 1, characterized in that, In step three, the silver solution used in the photocatalytic deposition method comprises the following components: silver nitrate 3-5 g / L, ethanol 0.2-0.6 g / L, glyceryl tristearate 0.2-0.5 g / L, and photocatalyst 0.05-0.1 g / L.
3. The method for preparing composite silver-plated copper foil according to claim 2, characterized in that, The photocatalyst was prepared by the following method: (1) Prepare a copper diglycine complex by mixing Cu(NO3)2•3H2O and glycine in distilled water; (2) The copper diglycine complex and titanium isopropoxide were simultaneously added dropwise to a mixed solution of ethanol and water, and the mixture was then refluxed for at least 48 h to obtain a colloidal solution, which was then dried and calcined to obtain the photocatalyst.
4. The method for preparing composite silver-plated copper foil according to claim 3, characterized in that, The molar ratio of titanium isopropoxide, ethanol, and water is (1~1.5):(2~3):(8~10); the temperature of the distilled water is 85-90℃; the temperature of the mixed solution of ethanol and water is 65-70℃; the calcination temperature is 400-500℃, and the calcination time is 4-6 h.
5. The method for preparing composite silver-plated copper foil according to claim 3, characterized in that, The photocatalytic deposition method uses a 350-450W Xe lamp with a light power density of 1500-2000 mW / cm². 2 The Xe lamp was placed 60 mm away from the reactor and the irradiation time was 1-3 h.
6. The method for preparing composite silver-plated copper foil according to claim 1, characterized in that, In step four, the electrolyte used in the alloying treatment is a Ni-Co alloy solution containing rare earth elements, wherein the rare earth elements are selected from one or more of La, Ce, Pr, and Nd.
7. The method for preparing composite silver-plated copper foil according to claim 6, characterized in that, In step four, the electrolyte comprises: potassium pyrophosphate 120-200 g / L, cobalt sulfate 2-5 g / L, nickel sulfate 5-10 g / L, rare earth elements 10-50 mg / L, sodium chloride 1-2 g / L, and sodium dodecyl sulfate 0.1-0.5 g / L; the alloying process conditions are: pH 7-9, temperature 35-45℃, and current density 1-3.5 A / dm³. 2 The electroplating time is 5-10 seconds.
8. The method for preparing composite silver-plated copper foil according to claim 1, characterized in that, In step five, an anti-oxidation treatment solution is used for anti-oxidation treatment. The concentration of hexavalent chromium ions in the anti-oxidation treatment solution is 1.5-3 g / L; the pH value of the anti-oxidation treatment is 12-14, the temperature is 30-36℃, and the current density is 4-6 A / dm³. 2 The electroplating time is 5-10 s; the silane coupling agent coating treatment involves washing the anti-oxidation treated composite copper foil with water and then spraying it with a silane coupling agent with a volume concentration of 0.2%; the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, vinyltrimethoxysilane or vinyltriethoxysilane; the drying temperature is 200-250℃ and the time is 8-12 s.
9. The method for preparing composite silver-plated copper foil according to claim 1, characterized in that, In step two, the roughening treatment is performed as follows: the acid-washed copper foil is electroplated in a roughening solution, the composition of which is: a concentration of divalent copper ions of 8-20 g / L and a sulfuric acid concentration of 150-200 g / L; the roughening treatment temperature is 25-30℃, and the current density is 8-10 A / dm³. 2 The electroplating time is 8-12 s; the curing solution for the curing treatment has the following composition: a concentration of divalent copper ions of 60-80 g / L and a concentration of sulfuric acid of 80-100 g / L; the curing temperature is 40-45℃ and the current density is 5-8 A / dm³. 2 Electroplating time is 6-8 seconds.
10. A composite silver-plated copper foil, characterized in that, The composite silver-plated copper foil was prepared using the method described in any one of claims 1 to 9.