High-corrosion-resistance oxygen-free copper and preparation method thereof
By constructing a composite structure of a nano-copper transition layer, a porous Al-Cr-Cu metal layer, and a protective layer on an oxygen-free copper substrate, and combining it with a coating system of modified polyarylene ether sulfone-based curing agent and imidazole curing agent, the corrosion resistance problem of oxygen-free copper in a humid salt spray environment was solved, achieving a balance between high corrosion resistance and conductivity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-24
- Publication Date
- 2026-03-31
AI Technical Summary
Existing oxygen-free copper has insufficient corrosion resistance in humid or salt spray environments containing chloride ions, and traditional anti-corrosion technologies cannot simultaneously achieve both conductivity and corrosion resistance.
A composite structure consisting of a nano-copper transition layer, a porous Al-Cr-Cu metal layer, and a protective layer is sequentially constructed on an oxygen-free copper substrate. The porous layer is formed by magnetron sputtering and treatment with sodium hydroxide solution. Combined with a coating system of modified polyarylene ether sulfone-based curing agent and imidazole curing agent, the interfacial bonding and corrosion resistance are improved.
It significantly improves the corrosion resistance and interfacial bonding of oxygen-free copper, avoids ion bombardment damage, and ensures both conductivity and corrosion resistance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of surface treatment technology, specifically to a highly corrosion-resistant oxygen-free copper and its preparation method. Background Technology
[0002] With the development of fields such as electronics, electrical engineering, aerospace, and marine engineering, higher requirements have been placed on the electrical and thermal conductivity and long-term environmental stability of copper materials. Although oxygen-free copper has excellent electrical conductivity, its corrosion resistance in humid or salt spray environments containing chloride ions is relatively insufficient.
[0003] Existing oxygen-free copper corrosion protection technologies mainly include electroplating, electroless plating, and coating with anti-corrosion coatings. Although electroplating and electroless plating can improve corrosion resistance, the coating will increase its surface resistivity. Moreover, after traditional anti-corrosion coatings are applied, the coating is prone to blistering and cracking, and nano-anti-corrosion fillers are prone to agglomeration in the coating, making it difficult to exert the optimal protective effect.
[0004] To improve coating adhesion and balance surface resistance, researchers have attempted to directly apply Ar to oxygen-free copper substrates after cleaning and drying. + Ion bombardment improves surface roughness, followed by coating with a protective coating and curing. However, excessive ion bombardment energy can damage the oxygen-free copper surface and increase interfacial contact resistance; insufficient energy significantly reduces coating adhesion, leading to decreased corrosion resistance.
[0005] In summary, the preparation of a highly corrosion-resistant oxygen-free copper is of great significance. Summary of the Invention
[0006] The purpose of this invention is to provide a highly corrosion-resistant oxygen-free copper and its preparation method, so as to solve the problems raised in the prior art.
[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing highly corrosion-resistant oxygen-free copper includes the following steps: Step 1: A nano-copper transition layer and an Al-Cr-Cu metal layer are sequentially magnetron sputtered onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; Step 2: Immerse the oxygen-free copper substrate A in sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B. Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer, and obtain highly corrosion-resistant oxygen-free copper; The porosity of the porous Al-Cr-Cu metal layer is 24~35%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%.
[0008] A more optimized process for the nano-copper transition layer is as follows: using copper metal as the target material, under argon gas at 40-60 sccm, sputtering with a power of 70-90 W and a sputtering temperature of 50-60℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
[0009] In this method, oxygen-free copper is sequentially cleaned with acetone and dried with nitrogen to obtain an oxygen-free copper matrix.
[0010] A more optimized process for the Al-Cr-Cu metal layer is as follows: using copper-chromium alloy and aluminum metal as targets, under argon gas at 40~60 sccm, with the aluminum metal target having a power of 120~150W, the copper-chromium alloy target having a power of 50~100W, and the sputtering temperature at 150~170℃, a dual-target magnetron sputtering is performed to form the Al-Cr-Cu metal layer.
[0011] In a more optimized form, the mass ratio of copper to chromium in the copper-chromium alloy is 1:(4~6).
[0012] In a more optimized form, the raw materials of the protective coating include the following components: by mass parts, 60-80 parts of bisphenol F type epoxy resin, 20-30 parts of polyarylether sulfone-based curing agent, 7-8 parts of imidazole curing agent, 1-2 parts of defoamer, 1-2 parts of leveling agent, and 30-50 parts of solvent.
[0013] A more optimized method for preparing the polyarylene ether sulfone-based curing agent is as follows: (1) Add γ-aminopropyltriethoxysilane and nano zinc oxide to an ethanol aqueous solution and mix evenly. Stir at 60~70℃ for 2~4 hours, wash and dry to obtain aminated nano zinc oxide; add aminated nano zinc oxide and vanillin to anhydrous ethanol and stir at 40~50℃ in the dark for 5~7 hours, wash and dry to obtain vanillin modified nano zinc oxide; (2) Under a nitrogen atmosphere, vanillin-modified nano zinc oxide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 4,4'-difluorodiphenyl sulfone were added to N-methylpyrrolidone and stirred until homogeneous. The mixture was stirred at 60-70°C for 30-40 minutes. Potassium carbonate and a dehydrating agent were added, and the mixture was heated to 110-120°C and stirred for 6-8 hours. The mixture was then heated to 160-170°C and stirred for 6-8 hours. After cooling to 90-110°C, the mixture was added to ice water to precipitate the precipitate. The precipitate was washed, dried, and ground to obtain a polyarylene ether sulfone-based curing agent.
[0014] In a more optimized manner, the mass ratio of γ-aminopropyltriethoxysilane to nano zinc oxide is 2:(0.5~1); the raw material for the vanillin-modified nano zinc oxide includes the following components: by mass parts, 6~8 parts of aminated nano zinc oxide, 15~17 parts of vanillin, and 80~100 parts of anhydrous ethanol. The raw materials of the polyarylene ether sulfone-based curing agent include the following components: by mass, 8-10 parts vanillin-modified nano zinc oxide, 5-9 parts 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 10-12 parts 4,4'-difluorodiphenyl sulfone, 80-100 parts N-methylpyrrolidone, 5-8 parts potassium carbonate, and 30-40 parts water-removing agent.
[0015] In this scheme, the nano-zinc oxide is spherical with an average particle size of 10~15nm.
[0016] A more optimized curing process is as follows: under a pressure of 0.3~0.5MPa, the temperature is raised to 70~90℃ at a rate of 1~2℃ / min and held for 40~60 minutes, then the temperature is raised to 130~150℃ and held for 2~3 hours.
[0017] A method for preparing highly corrosion-resistant oxygen-free copper is disclosed. The highly corrosion-resistant oxygen-free copper comprises an oxygen-free copper substrate and, sequentially disposed on its surface, a nano-copper transition layer, an Al-Cr-Cu metal layer, and a protective layer. The thickness of the nano-copper transition layer is 2-4 μm; the thickness of the Al-Cr-Cu metal layer is 5-15 μm; and the thickness of the protective layer is 3-6 μm.
[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention solves the problems of poor corrosion resistance, weak interfacial bonding, and difficulty in achieving both conductivity and corrosion resistance in traditional oxygen-free copper materials by sequentially constructing a composite structure of a nano-copper transition layer, a porous Al-Cr-Cu metal layer, and a protective layer on an oxygen-free copper substrate.
[0019] This invention involves magnetron sputtering a nano-copper transition layer onto the surface of an oxygen-free copper substrate. Since both the oxygen-free copper substrate and the nano-copper transition layer are copper materials, a metallurgical interface can be formed during magnetron sputtering. Therefore, ion bombardment pretreatment of the oxygen-free copper substrate is unnecessary, avoiding the damage and resistivity increase caused by ion bombardment. Subsequently, Ar... + The surface roughness of the nano-copper transition layer is increased by ion bombardment, followed by magnetron sputtering deposition of an Al-Cr-Cu metal layer. The layer is then soaked in sodium hydroxide solution for dealuminization, forming a porous Al-Cr-Cu metal layer. The copper component in the porous layer works synergistically with the roughening effect of ion bombardment to further enhance the bonding strength between the porous Al-Cr-Cu metal layer and the nano-copper transition layer.
[0020] Applying a protective coating to the surface of a porous Al-Cr-Cu metal layer allows the coating to fully penetrate the pores, significantly improving the interfacial bonding effect. This invention employs a compound system of bisphenol F epoxy resin, modified polyarylene ether sulfone-based curing agent, and imidazole curing agent. The imidazole groups can coordinate with the metal on the surface of the porous Al-Cr-Cu metal layer, further enhancing its corrosion resistance. By introducing hydroxyl-containing vanillin-modified nano-zinc oxide into the polyarylene ether sulfone, the coating's corrosion resistance can be significantly enhanced; simultaneously, the use of excessively large zinc oxide particles is avoided to prevent its difficulty in penetrating the pores and subsequent stacking, ensuring the overall performance of the material.
[0021] This invention first modifies the surface of nano zinc oxide and then introduces it into a polyarylether sulfone-based curing agent. This avoids the direct coordination of imidazole groups with zinc ions, which would cause the coating to become cloudy, thus ensuring the stability of the coating and improving the corrosion resistance. Detailed Implementation
[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0023] In the following specific embodiments, the parts are by weight. In this embodiment, it should be noted that there are no special restrictions on the purchase manufacturers of all the raw materials involved in this invention. Exemplary examples include: 4,4'-difluorodiphenyl sulfone, CAS number 383-29-9; γ-aminopropyltriethoxysilane, CAS number 919-30-2; nano zinc oxide, model ZnO-N10, with an average particle size of 10nm; 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, CAS number 83558-87-6; vanillin, CAS number 121-33-5; defoamer, BYK-066N; leveling agent, BYK-333; bisphenol F type epoxy resin, bisphenol F diglycidyl ether; imidazole curing agent, 2-ethyl-4-methylimidazolium, CAS number 931-36-2; and oxygen-free copper matrix, brand name TU1.
[0024] Pre-preparation: The preparation method of polyarylene ether sulfone-based curing agent is as follows: (1) Weigh γ-aminopropyltriethoxysilane and nano zinc oxide at a mass ratio of 2:0.7; add γ-aminopropyltriethoxysilane and nano zinc oxide to an ethanol aqueous solution (ethanol content is 80wt%) and mix evenly, stir at 60℃ for 2 hours, wash and dry to obtain aminated nano zinc oxide; add 15 parts vanillin to 100 parts anhydrous ethanol and stir, add 8 parts aminated nano zinc oxide and mix evenly, stir at 40℃ in the dark for 6 hours, wash and dry to obtain vanillin modified nano zinc oxide; (2) Under a nitrogen atmosphere Eight parts of vanillin-modified nano zinc oxide, five parts of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and twelve parts of 4,4'-difluorodiphenyl sulfone were added to 100 parts of N-methylpyrrolidone and stirred until homogeneous. The mixture was stirred at 60°C for 40 minutes, then seven parts of potassium carbonate and 35 parts of dehydrating agent were added. The mixture was heated to 120°C and stirred for 6 hours, then heated to 165°C and stirred for another 8 hours (after removing the dehydrating agent, the temperature was raised to 165°C). The mixture was cooled to 100°C and added to ice water to precipitate the precipitate. Under nitrogen protection, the precipitate was washed sequentially with deionized water and then hot-washed three times with anhydrous ethanol. After drying and grinding, the polyarylene ether sulfone-based curing agent was obtained.
[0025] Example 1: A method for preparing highly corrosion-resistant oxygen-free copper, comprising the following steps: Step 1: Sequentially magnetron sputter a 3.2 μm thick nano-copper transition layer and a 10 μm thick Al-Cr-Cu metal layer onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under 40 sccm argon gas, with a sputtering power of 70 W and a sputtering temperature of 50℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
[0026] Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, voltage of -220 V, and time of 30 minutes. The specific process of Al-Cr-Cu metal layer is as follows: copper-chromium alloy and aluminum metal are used as target materials. The mass ratio of copper to chromium in the copper-chromium alloy is 1:5. Under 40sccm argon gas, dual-target magnetron sputtering is performed with an aluminum metal target power of 120W, a copper-chromium alloy target power of 90W, and a sputtering temperature of 170℃. Step 2: Immerse the oxygen-free copper substrate A in a 0.1M sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B; the porosity of the porous Al-Cr-Cu metal layer is 32.7%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%; Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by mass, 80 parts bisphenol F type epoxy resin, 20 parts polyarylether sulfone-based curing agent, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 35 parts solvent (the 35 parts solvent include 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0027] Example 2, a method for preparing highly corrosion-resistant oxygen-free copper, includes the following steps: Step 1: Sequentially magnetron sputter a 3.2 μm thick nano-copper transition layer and a 10 μm thick Al-Cr-Cu metal layer onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under 40 sccm argon gas, with a sputtering power of 70 W and a sputtering temperature of 50℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
[0028] Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, voltage of -220 V, and time of 30 minutes. The specific process of Al-Cr-Cu metal layer is as follows: copper-chromium alloy and aluminum metal are used as target materials. The mass ratio of copper to chromium in the copper-chromium alloy is 1:5. Under 40sccm argon gas, dual-target magnetron sputtering is performed with an aluminum metal target power of 120W, a copper-chromium alloy target power of 90W, and a sputtering temperature of 170℃. Step 2: Immerse the oxygen-free copper substrate A in a 0.1M sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B; the porosity of the porous Al-Cr-Cu metal layer is 32.7%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%; Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by mass, 80 parts bisphenol F type epoxy resin, 25 parts polyarylether sulfone-based curing agent, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0029] Example 3, a method for preparing highly corrosion-resistant oxygen-free copper, includes the following steps: Step 1: Sequentially magnetron sputter a 3.2 μm thick nano-copper transition layer and a 10 μm thick Al-Cr-Cu metal layer onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under 40 sccm argon gas, with a sputtering power of 70 W and a sputtering temperature of 50℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
[0030] Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, voltage of -220 V, and time of 30 minutes. The specific process of Al-Cr-Cu metal layer is as follows: copper-chromium alloy and aluminum metal are used as target materials. The mass ratio of copper to chromium in the copper-chromium alloy is 1:5. Under 40sccm argon gas, dual-target magnetron sputtering is performed with an aluminum metal target power of 120W, a copper-chromium alloy target power of 90W, and a sputtering temperature of 170℃. Step 2: Immerse the oxygen-free copper substrate A in a 0.1M sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B; the porosity of the porous Al-Cr-Cu metal layer is 32.7%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%; Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by mass, 80 parts bisphenol F type epoxy resin, 30 parts polyarylether sulfone-based curing agent, 8 parts imidazole curing agent, 1.2 parts defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0031] Comparative Example 1 is based on Example 2, but without the porous Al-Cr-Cu metal layer; the other operation steps are the same. Step 1: Sequentially magnetron sputter a 3.2 μm thick nano-copper transition layer onto the surface of the oxygen-free copper substrate; thus obtaining oxygen-free copper substrate A; The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under 40 sccm argon gas, with a sputtering power of 70 W and a sputtering temperature of 50℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
[0032] Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, voltage of -220 V, and time of 30 minutes. Step 2: Coat the surface of oxygen-free copper substrate A with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by mass, 80 parts bisphenol F type epoxy resin, 25 parts polyarylether sulfone-based curing agent, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0033] Comparative Example 2, based on Example 2, involves Ar oxidation of an oxygen-free copper substrate. + Ion bombardment followed by direct application of protective coating; the remaining steps are the same. Step 1: Ar + Pre-prepared oxygen-free copper A was obtained by bombarding the surface of an oxygen-free copper substrate with ions for 30 minutes; Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, and voltage of -220 V; Step 2: Coat the surface of the pre-made oxygen-free copper A with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by weight, 80 parts bisphenol F type epoxy resin, 25 parts polyarylether sulfone-based curing agent, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 15 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0034] Comparative Example 3 is based on Example 2, but without the nano-copper layer; the remaining operation steps are the same. Step 1: Ar + The surface of the oxygen-free copper substrate was bombarded with ions for 30 minutes, and an Al-Cr-Cu metal layer with a thickness of 10 μm was sputtered by magnetron sputtering; thus, oxygen-free copper substrate A was obtained. Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, and voltage of -220 V; The specific process of Al-Cr-Cu metal layer is as follows: copper-chromium alloy and aluminum metal are used as target materials. The mass ratio of copper to chromium in the copper-chromium alloy is 1:5. Under 40sccm argon gas, dual-target magnetron sputtering is performed with an aluminum metal target power of 120W, a copper-chromium alloy target power of 90W, and a sputtering temperature of 170℃. Step 2: Immerse the oxygen-free copper substrate A in a 0.1M sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B; the porosity of the porous Al-Cr-Cu metal layer is 32.7%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%; Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components: by mass, 80 parts bisphenol F type epoxy resin, 25 parts polyarylether sulfone-based curing agent, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0035] Comparative Example 4 is based on Example 2, in which nano-zinc oxide is directly added to the protective coating; the remaining operation steps are the same. Pre-preparation: The preparation method of polyarylene ether sulfone-based curing agent is as follows: Under a nitrogen atmosphere, 9 parts of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and 10 parts of 4,4'-difluorodiphenyl sulfone are added to 100 parts of N-methylpyrrolidone and stirred evenly. The mixture is stirred at 60°C for 40 minutes, then 7 parts of potassium carbonate and 35 parts of dehydrating agent are added. The mixture is heated to 120°C and stirred for 6 hours, then heated to 165°C and stirred for another 7 hours (after removing the dehydrating agent, the temperature is raised to 165°C again). The mixture is cooled to 100°C and added to ice water to precipitate the precipitate. Under nitrogen protection, the precipitate is washed sequentially with deionized water and then hot-washed three times with anhydrous ethanol. After drying and grinding, the polyarylene ether sulfone-based curing agent is obtained. Step 1: Sequentially magnetron sputter a 3.2 μm thick nano-copper transition layer and a 10 μm thick Al-Cr-Cu metal layer onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under 40 sccm argon gas, with a sputtering power of 70 W and a sputtering temperature of 50℃; then Ar...+ Ions bombard the surface to form a nano-copper transition layer.
[0036] Ar + The process conditions for ion bombardment are: argon gas, pressure of 2 Pa, voltage of -220 V, and time of 30 minutes. The specific process of Al-Cr-Cu metal layer is as follows: copper-chromium alloy and aluminum metal are used as target materials. The mass ratio of copper to chromium in the copper-chromium alloy is 1:5. Under 40sccm argon gas, dual-target magnetron sputtering is performed with an aluminum metal target power of 120W, a copper-chromium alloy target power of 90W, and a sputtering temperature of 170℃. Step 2: Immerse the oxygen-free copper substrate A in a 0.1M sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B; the porosity of the porous Al-Cr-Cu metal layer is 32.7%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%; Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer with a thickness of 4μm, and obtain highly corrosion-resistant oxygen-free copper; The raw materials for the protective coating include the following components by weight: 80 parts bisphenol F type epoxy resin, 25 parts polyarylether sulfone-based curing agent, 8.75 parts nano zinc oxide, 7 parts imidazole curing agent, 1 part defoamer, 1 part leveling agent, and 40 parts solvent (the 40 parts solvent includes 25 parts N,N-dimethylacetamide and 10 parts cyclohexanone). The curing process conditions are as follows: under a pressure of 0.3 MPa, the temperature is raised to 80°C at a rate of 2°C / min and held for 60 minutes, then the temperature is raised to 140°C and held for 2.5 hours.
[0037] Test 1: The composition and properties of the oxygen-free copper substrate were tested, as shown in Table 1; Table 1
[0038] Test 2: (1) According to the GB / T10125-2021 test standard, the highly corrosion-resistant oxygen-free copper prepared in Examples 1-3 and Comparative Examples 1-4 was placed in a salt spray test chamber, a sodium chloride solution with a concentration of 50 g / L was prepared, the temperature was set at 35 ± 2 ℃, and the spray pressure was 1 kg / cm. 2 The time is 168 hours, and the pH is adjusted to the specified value; observe and record the surface corrosion resistance. (2) According to the test method of ASTM D4541-22, the adhesion of the protective layer of Examples 1-3 and Comparative Examples 1-4 was tested by a pull-out tester; the 8005 epoxy resin adhesive was applied to the test point, and a 10mm spindle was pressed on the test surface. Excess adhesive was squeezed out by applying pressure and the adhesive was allowed to fully cure; the spindle was embedded and fixed by the pull-out tester and a pull-out test was performed at a pull-out speed of 1MPa / s. Table 2
[0039] Conclusion: In Example 3, the increased content of polyarylene ether sulfone-based curing agent increased the viscosity of the coating system, reducing its ability to penetrate the pores of the porous Al-Cr-Cu metal layer during coating, thus slightly reducing adhesion performance, but the corrosion resistance still met the requirements; Comparative Example 1 was based on Example 2, but without the porous Al-Cr-Cu metal layer; in this scheme, the porous Al-Cr-Cu metal layer and the protective layer played a role in corrosion resistance, the porous Al-Cr-Cu metal layer improved surface roughness, thereby improving interlayer bonding, while the nano-copper layer was mainly used to reduce the surface resistance of the oxygen-free copper layer, but in Comparative Example 1, the absence of the porous Al-Cr-Cu metal layer led to a significant decrease in the performance of the highly corrosion-resistant oxygen-free copper; Comparative Example 2 was based on Example 2, with the oxygen-free copper substrate subjected to Ar... + Ion bombardment, directly applied to the protective coating, resulted in a significant decrease in the performance of Comparative Example 2. Comparative Example 3, based on Example 2, did not have a nano-copper layer. The surface of Comparative Example 3 showed no corrosion, and its pull-out adhesion was close to that of Comparative Example 2. Comparative Example 4, based on Example 2, had nano-zinc oxide directly added to the protective coating. This caused the imidazole curing agent to first coordinate with the zinc ions in the nano-zinc oxide, resulting in slight turbidity in the protective coating. After coating, the nanomaterials partially stacked, thus leading to a decrease in performance.
[0040] Test 3: The resistivity (μΩ·cm) of the nano-copper transition layer and porous Al-Cr-Cu metal layer prepared by magnetron sputtering in Example 2 and Comparative Example 3 was tested. Table 3
[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
Claims
1. A method for preparing highly corrosion-resistant oxygen-free copper, characterized in that: The following steps are included: Step 1: A nano-copper transition layer and an Al-Cr-Cu metal layer are sequentially magnetron sputtered onto the surface of an oxygen-free copper substrate to obtain oxygen-free copper substrate A; Step 2: Immerse the oxygen-free copper substrate A in sodium hydroxide solution to form a porous Al-Cr-Cu metal layer; thus obtaining the oxygen-free copper substrate B. Step 3: Coat the surface of oxygen-free copper substrate B with a protective coating, cure it to form a protective layer, and obtain highly corrosion-resistant oxygen-free copper; The porosity of the porous Al-Cr-Cu metal layer is 24~35%, and the aluminum content in the porous Al-Cr-Cu metal layer is <2.7wt%.
2. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 1, characterized in that: The specific process for the nano-copper transition layer is as follows: using copper metal as the target material, under argon gas at 40-60 sccm, with a sputtering power of 70-90 W and a sputtering temperature of 50-60℃; then Ar... + Ions bombard the surface to form a nano-copper transition layer.
3. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 1, characterized in that: The specific process of the Al-Cr-Cu metal layer is as follows: using copper-chromium alloy and aluminum metal as target materials, under argon gas at 40~60 sccm, with the aluminum metal target having a power of 120~150W, the copper-chromium alloy target having a power of 50~100W, and the sputtering temperature at 150~170℃, a dual-target magnetron sputtering is performed to form the Al-Cr-Cu metal layer.
4. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 3, characterized in that: In the copper-chromium alloy, the mass ratio of copper to chromium is 1:(4~6).
5. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 1, characterized in that: The raw materials of the protective coating include the following components: by mass, 60-80 parts of bisphenol F type epoxy resin, 20-30 parts of polyarylether sulfone-based curing agent, 7-8 parts of imidazole curing agent, 1-2 parts of defoamer, 1-2 parts of leveling agent, and 30-50 parts of solvent.
6. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 5, characterized in that: The preparation method of the polyarylene ether sulfone-based curing agent is as follows: (1) Add γ-aminopropyltriethoxysilane and nano zinc oxide to an ethanol aqueous solution and mix evenly. Stir at 60~70℃ for 2~4 hours, wash and dry to obtain aminated nano zinc oxide; Aminated nano-zinc oxide and vanillin were added to anhydrous ethanol and stirred at 40-50°C in the dark for 5-7 hours. After washing and drying, vanillin-modified nano-zinc oxide was obtained. (2) Under a nitrogen atmosphere, vanillin-modified nano zinc oxide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 4,4'-difluorodiphenyl sulfone were added to N-methylpyrrolidone and stirred until homogeneous. The mixture was stirred at 60-70°C for 30-40 minutes. Potassium carbonate and a dehydrating agent were added, and the mixture was heated to 110-120°C and stirred for 6-8 hours. The mixture was then heated to 160-170°C and stirred for 6-8 hours. After cooling to 90-110°C, the mixture was added to ice water to precipitate the precipitate. The precipitate was washed, dried, and ground to obtain a polyarylene ether sulfone-based curing agent.
7. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 6, characterized in that: The mass ratio of γ-aminopropyltriethoxysilane to nano zinc oxide is 2:(0.5~1); the raw material of the vanillin-modified nano zinc oxide includes the following components: by mass parts, 6~8 parts of aminated nano zinc oxide, 15~17 parts of vanillin, and 80~100 parts of anhydrous ethanol. The raw materials of the polyarylene ether sulfone-based curing agent include the following components: by mass, 8-10 parts vanillin-modified nano zinc oxide, 5-9 parts 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 10-12 parts 4,4'-difluorodiphenyl sulfone, 80-100 parts N-methylpyrrolidone, 5-8 parts potassium carbonate, and 30-40 parts water-removing agent.
8. The method for preparing highly corrosion-resistant oxygen-free copper according to claim 1, characterized in that: The curing process conditions are as follows: under a pressure of 0.3~0.5MPa, the temperature is raised to 70~90℃ at a rate of 1~2℃ / min and held for 40~60 minutes, and then the temperature is raised to 130~150℃ and held for 2~3 hours.
9. The method for preparing highly corrosion-resistant oxygen-free copper according to any one of claims 1 to 8, characterized in that: The highly corrosion-resistant oxygen-free copper comprises an oxygen-free copper substrate, and a nano-copper transition layer, an Al-Cr-Cu metal layer, and a protective layer sequentially disposed on its surface; the thickness of the nano-copper transition layer is 2~4μm; the thickness of the Al-Cr-Cu metal layer is 5~15μm; and the thickness of the protective layer is 3~6μm.