Surface treatment method of copper-aluminum composite foil and surface-treated copper-aluminum composite foil

Abstract

The invention relates to the field of metal surface treatment, in particular to a surface treatment method of a copper-aluminum composite foil and the surface-treated copper-aluminum composite foil. According to the surface treatment method for the copper-aluminum composite foil, the production process is continuous and efficient, and belongs to a new process route; technological parameters of each functional tank belong to a new technological formula; according to the continuous production electroplating line for degreasing cleaning, copper plating thickening and copper plating surface coarsening and passivation of the copper-aluminum composite foil in the electroplating process, the surface binding force of the copper-aluminum composite foil, the appearance of a copper layer and the performance of folding resistance, peel strength resistance, high temperature resistance and normal-temperature storage can be improved, and the requirement of downstream customers for higher performance of the copper-aluminum composite foil is met. Tests show that the copper-aluminum composite foil subjected to surface treatment through the surface treatment method has the advantages that the surface dyne value is larger than or equal to 40, the good binding force is achieved, the peel strength is larger than or equal to 0.8 N / mm, and the high-temperature-resistant and oxidation-resistant performance that the copper-aluminum composite foil can be stored at the normal temperature for more than or equal to 6 months and can resist the high temperature of 180 DEG C for 1 hour is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal surface treatment, and particularly relates to a surface treatment method of copper-aluminum composite foil and a surface treated copper-aluminum composite foil. BACKGROUND

[0002] The initial copper-aluminum composite material produced in China is mainly prepared by explosive compounding, which has high cost, low efficiency, and can only produce single plates. The composite copper-aluminum bar also only stays in the stages of composite casting and hot permeation rolling, and the product quality is unstable, and there is a problem of aluminum oxidation that cannot be solved.

[0003] The prior art adopts a vacuum magnetron sputtering + electroplating (sputtering method) process to prepare the copper-aluminum composite foil, performs surface activation modification treatment on the aluminum foil substrate to improve the bonding force between the thin film substrate and the metal layer. The vacuum physical vapor deposition technology is adopted to form a transition layer metal layer and a copper seed layer on the base film, and the base film adopts infrared heating and vacuum surface activation modification technology and special vacuum auxiliary technology to improve the plating layer bonding force, thereby solving the problem of low bonding force between the base film aluminum and the copper metal layer, and the peeling strength is greater than or equal to 1.1 N / mm. This process adopts a roll-to-roll production process, has high production efficiency, is simple and easy to operate, is easy to control, and has low production cost. Single and double-sided materials can be easily made, and customized products can also be made according to customer requirements, so as to enter the copper foil market with the advantages of low cost, high quality and high yield. The cost reduction and efficiency improvement are significant, and the development trend of composite materials is light, thin, short and small.

[0004] However, although the vacuum magnetron sputtering + electroplating (sputtering method) process for preparing the copper-aluminum composite foil solves the problem of the bonding force between the aluminum and the copper metal layer, the downstream customers have higher requirements for the bonding force between the double sides of the copper-aluminum composite material and PET or PI and other materials, the high temperature resistance of the double sides of the copper-aluminum composite material, and the surface peeling strength of the double sides of the copper-aluminum composite material.

[0005] The vacuum magnetron sputtering + electroplating (sputtering method) process for preparing the copper-aluminum composite foil cannot meet the use requirements of downstream customers. Taking the application of a copper-aluminum composite foil with 50 μm aluminum foil + 4 μm copper in the LED field as an example. After the 50 μm aluminum foil is subjected to magnetron sputtering alloying on one side, it enters the copper plating process to form a 4 μm copper layer, and then is cut into products for delivery. In the LED process, the bonding force between the aluminum surface and PET is poor, and the copper surface is oxidized and discolored during the heating and bonding process.

[0006] Taking the application of a copper-aluminum composite foil with 50 μm aluminum foil + 1 μm copper on both sides in the copper-clad plate field as an example. After the 50 μm aluminum foil is subjected to magnetron sputtering alloying on one side, it enters the copper plating process to form a 1 μm copper layer on both sides, and then is cut into products for delivery. The downstream customers press PI on both sides of the copper-aluminum composite foil, and problems such as poor bonding force and oxidation occur during the production process. SUMMARY

[0007] Therefore, the technical problem to be solved by the present application is to provide a surface treatment method of a copper-aluminum composite foil and a surface-treated copper-aluminum composite foil, and the surface treatment process provided by the present application can improve the surface bonding force, high-temperature resistance, oxidation resistance and peeling resistance of the copper-aluminum composite foil.

[0008] The present application provides a surface treatment method of a copper-aluminum composite foil, comprising the following steps:

[0009] The copper-aluminum composite foil to be surface-treated is subjected to hydrocarbon degreasing, and then the copper layer of the copper-aluminum composite foil is subjected to copper plating thickening, copper layer roughening and copper layer passivation in sequence;

[0010] The temperature of the copper layer roughening is 15-18 DEG C, and the time of the copper layer roughening is 8-12 s;

[0011] The copper layer roughening is carried out in a copper layer roughening solution, and the copper layer roughening solution comprises:

[0012] Copper ions: 10-15 g / L;

[0013] Sulfuric acid: 210-220 g / L;

[0014] Chloride ions: 20-30 ppm;

[0015] Potassium dichromate: 0.3-0.6 g / L;

[0016] Nickel sulfate: 0.8-1.2 g / L.

[0017] The surface treatment method of the copper-aluminum composite foil provided by the present application is directed to a copper-aluminum composite foil prepared by vacuum magnetron sputtering and electroplating (sputtering method) process, and the copper-aluminum composite foil to be surface-treated comprises: an aluminum layer; an alloy layer disposed on the aluminum layer, the alloy layer being a copper-chromium alloy layer, a copper-nickel alloy layer, a nickel-zinc alloy layer or a nickel-chromium alloy layer; the alloy layer is beneficial to improve the bonding force with the subsequent thickened copper layer, and the thickness of the alloy layer is preferably 50-80 nm; a copper layer disposed on the alloy layer, and the copper layer is specifically a copper nano layer.

[0018] Firstly, the copper-aluminum composite foil to be surface-treated is subjected to hydrocarbon degreasing, and specifically, the copper-aluminum composite foil to be surface-treated is subjected to hydrocarbon degreasing in a light hydrocarbon degreasing cleaning material; the 20 DEG C density of the light hydrocarbon degreasing cleaning material is 0.725 g / cm 3 ~ 0.745 g / cm 3The light hydrocarbon degreasing cleaning material has a flash point of 40 DEG C or above, a pressure resistance value of 20kV or above, and a 98% distillate distillation range of 160 DEG C to 200 DEG C. The present application has the advantages of strong cleaning ability, fast evaporation speed, non-toxicity, environmental protection, safety, no corrosion to metal, no residue, and the like.

[0019] After the copper-aluminum composite foil to be surface treated is subjected to the hydrocarbon degreasing, the copper-aluminum composite foil is subjected to baking, and then air cooling is performed to reduce the temperature of the copper-aluminum composite foil, so that copper plating thickening can be performed. The main purpose of the baking is to dry the hydrocarbon degreasing agent on the surface of the material, and the temperature of the baking is 100 DEG C to 120 DEG C. A cooling fan is arranged at the outlet of the baking device, and air cooling is performed on the copper-aluminum composite foil after the baking, so that the temperature of the foil can be quickly reduced, and wrinkles of the foil caused by temperature difference entering the solution can be prevented.

[0020] After the copper-aluminum composite foil to be surface treated is subjected to the hydrocarbon degreasing, the copper-aluminum composite foil is subjected to copper plating thickening, and the thickness of the copper layer of the copper-aluminum composite foil after the copper plating thickening is 1um to 4um. The copper plating thickening is performed in a copper plating thickening solution, and specifically, one side of the copper layer of the copper-aluminum composite foil is immersed in the copper plating thickening solution. The temperature of the copper plating thickening is 24 DEG C to 30 DEG C. The time of the copper plating thickening is not particularly limited, and the thickness of the copper layer of the copper-aluminum composite foil after the copper plating thickening is 1um to 4um. The copper plating thickening solution comprises: copper ions 20g / L to 25g / L; sulfuric acid 130g / L to 160g / L; leveling agent 4mL / L to 6mL / L, preferably 5mL / L; brightener 4mL / L to 6mL / L, preferably 5mL / L. The copper plating thickening solution is used to thicken the copper layer, and the copper plating is bright and dense, and does not affect the bending resistance of the copper-aluminum composite material.

[0021] The copper-aluminum composite foil after copper plating thickening is subjected to copper layer roughening, and water washing is performed before copper layer roughening, so as to clean electrolyte on the surface of the copper-aluminum composite material, prevent cross contamination of components of different electroplating tanks, and ensure electroplating effect.The copper-aluminum composite foil after copper plating thickening is subjected to copper layer roughening, and rough copper particles are plated on the copper layer, so as to increase surface roughness; the temperature of the copper layer roughening is 15-18 DEG C, and the time of the copper layer roughening is 8-12 s.The copper layer roughening is performed in a copper layer roughening solution, and the copper layer roughening solution comprises: copper ions 10-15 g / L; sulfuric acid 210-220 g / L; chloride ions 20-30 ppm; potassium dichromate 0.3-0.6 g / L; and nickel sulfate 0.8-1.2 g / L.The copper layer is plated with a layer of larger copper particles in a sulfuric acid-copper sulfate system by using the principle of low copper, high acid and high current, so as to increase the roughness of the copper layer, and to facilitate PI pressing with downstream to manufacture printed circuit boards.The combined effect of additives, chloride ions, potassium dichromate and nickel sulfate, can better refine copper plating grains, and reduce copper tooth height and roughness.

[0022] The copper-aluminum composite foil after copper layer roughening is subjected to copper layer passivation, and water washing is performed before copper layer passivation, so as to clean electrolyte on the surface of the copper-aluminum composite material, prevent cross contamination of components of different electroplating tanks, and ensure electroplating effect.The copper-aluminum composite foil after copper layer roughening is subjected to copper layer passivation, and a high-temperature-resistant and oxidation-resistant alloy layer is plated on the surface of the copper layer; the temperature of the copper layer passivation is 35-40 DEG C, and the time of the copper layer passivation is 8-12 s.The copper layer passivation is performed in a copper layer passivation solution; the copper layer passivation solution comprises: zinc sulfate 3-3.5 g / L; chromic anhydride 0.5-0.8 g / L; and sodium hydroxide 20-25 g / L.The alloy passivation is performed to plate a zinc-chromium alloy layer on the copper layer of the copper-aluminum composite foil, so as to not only be high-temperature-resistant, but also ensure the daily storage copper surface at room temperature and the oxidation resistance of the copper-aluminum composite material, and the passivation solution does not corrode the aluminum surface; in addition, the copper layer passivation can improve the surface adhesion of the copper-aluminum composite foil, and the surface adhesion can be further improved by the combined effect of the aforementioned carbon-hydrogen degreasing, so as to achieve good adhesion of product surface of 40 or more and the performance requirement of high-temperature resistance of 180 DEG C for 1 hour.

[0023] The copper-aluminum composite foil after copper layer passivation is subjected to water washing, and the moisture on the surface of the copper-aluminum composite foil is dried by baking, and then the copper-aluminum composite foil after baking is subjected to air cooling by a cooling fan arranged at a baking outlet, so as to quickly reduce the temperature of the copper-aluminum composite foil, prevent wrinkles caused by temperature difference, and complete the surface treatment of the copper-aluminum composite foil.

[0024] The application also provides a surface-modified copper-aluminum composite foil, which is obtained by surface treatment of a copper-aluminum composite foil to be surface-treated by the surface treatment method according to any one of the technical solutions described above. The surface treatment of the copper-aluminum composite foil by the surface treatment method provided by the application not only realizes a good bonding force with a surface da Vinci value of greater than or equal to 40 and a peeling resistance of greater than or equal to 0.8 N / mm, but also realizes a high-temperature resistance and oxidation resistance with a storage time of greater than or equal to 6 months at room temperature and a high-temperature resistance of 1 hour at 180 DEG C.

[0025] The application provides a surface treatment method of a copper-aluminum composite foil and a surface-treated copper-aluminum composite foil. The surface treatment method of the copper-aluminum composite foil provided by the application is continuous and efficient, and belongs to a new process route. The process parameters of each functional tank belong to a new process formula. Through a continuous production electroplating line for the degreasing cleaning, copper plating thickening, roughening of the copper plating surface and passivation of the copper plating surface of the copper-aluminum composite foil developed independently, the surface bonding force, copper layer appearance, folding resistance, peeling resistance, high-temperature resistance and storage performance at room temperature of the copper-aluminum composite foil can be improved, and higher performance requirements of downstream customers for the copper-aluminum composite foil are met. Tests show that the copper-aluminum composite foil treated by the surface treatment method has a good bonding force with a surface da Vinci value of greater than or equal to 40 and a peeling resistance of greater than or equal to 0.8 N / mm, and realizes a high-temperature resistance and oxidation resistance with a storage time of greater than or equal to 6 months at room temperature and a high-temperature resistance of 1 hour at 180 DEG C. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A surface treatment production device for the copper-aluminum composite material is shown in the figure.

[0027] Figure 2 A detail view of the copper plating thickening electroplating tank is shown in the figure. DETAILED DESCRIPTION

[0028] The application discloses a surface treatment method of a copper-aluminum composite foil and a surface-treated copper-aluminum composite foil. Those skilled in the art can refer to the content herein and appropriately improve the process parameters to realize. It is particularly pointed out that all similar replacements and changes are obvious to those skilled in the art, and they are regarded as being included in the application. The method and application of the application have been described through preferred embodiments, and relevant personnel can obviously make changes or appropriate changes and combinations to the method and application herein without departing from the content, spirit and scope of the application, to realize and apply the technology of the application.

[0029] The application mainly optimizes the electroplating process after vacuum magnetron sputtering, and the process flow is unwinding-hydrocarbon degreasing-oven air cooling-copper plating thickening-water washing-copper layer roughening-water washing-copper layer passivation-water washing-oven air cooling-winding. According to the process requirements, a self-made surface treatment production device is used, as shown in the figure. Figure 1 ​Figure 1 This is a schematic diagram of the surface treatment production device of the copper-aluminum composite material of the present invention.

[0030] The present invention will be further described below with reference to the embodiments:

[0031] Example 1

[0032] (1) Open the book

[0033] The copper-aluminum composite foil to be surface treated is unrolled and then sent into a hydrocarbon degreasing tank;

[0034] The copper-aluminum composite foil to be surface treated is prepared by vacuum magnetron sputtering and electroplating (sputtering method), and its structure from bottom to top is an aluminum layer, a nickel-chromium alloy layer sputtered on the aluminum layer, and a copper layer electroplated on the nickel-chromium alloy layer.

[0035] (2) Hydrocarbon degreasing

[0036] After unwinding, the copper-aluminum composite foil to be surface treated enters the hydrocarbon degreasing tank, where the surface is subjected to hydrocarbon degreasing treatment using a hydrocarbon degreasing agent, and then is air-cooled in an oven.

[0037] The hydrocarbon degreasing agent used for hydrocarbon degreasing treatment is Tianjin Huayang Xinxing Technology SKH-620 hydrocarbon cleaning agent, and its indicators are shown in Table 1:

[0038] Table 1

[0039]

[0040] After the copper-aluminum composite foil is treated with hydrocarbon degreasing, the surface dyne value is tested to be ≥40.

[0041] (3) Oven air cooling

[0042] The copper-aluminum composite foil after hydrocarbon degreasing treatment is baked in an oven at 120°C to dry the hydrocarbon degreasing agent on the surface of the material, then cooled by air to reduce the material temperature, and then sent to the copper plating thickening electroplating tank.

[0043] (4) Copper plating thickening

[0044] After air cooling in the oven, the copper-aluminum composite foil is sent to the copper thickening electroplating tank, where copper thickening is carried out in the copper thickening solution in the copper thickening electroplating tank. The copper thickening is mainly carried out by plating 1μm of copper on the sputtered alloy layer of the aluminum foil. The copper plating is not only bright and dense, but also does not affect the bending resistance of the copper-aluminum composite foil. The process parameters for controlling the copper thickening solution during the copper thickening process are shown in Table 2:

[0045] Table 2

[0046]

[0047] To ensure the uniformity of the plating thickness, the vertical electroplating production mode is adopted for copper plating thickening, the anode plate is parallel to the two sides of the copper-aluminum composite material, the high-precision anode plate clamping groove is designed to ensure the precision of the pole distance, and the pole distance error is ensured to be ±0.1 mm. Figure 2 Figure 2 The details of the copper plating thickening electroplating tank are shown in the application.

[0048] (5) water washing

[0049] The copper-aluminum composite foil after copper plating thickening is sent into a cleaning tank for water washing, and then into a copper layer roughening tank.

[0050] (6) copper layer roughening

[0051] The copper-aluminum composite foil after water washing is subjected to copper layer roughening in the copper layer roughening solution in the copper layer roughening tank for 10 s. The process parameters of the copper layer roughening solution in the copper layer roughening process are shown in Table 3:

[0052] Table 3

[0053]

[0054] (5) water washing

[0055] The copper-aluminum composite foil after copper layer roughening is sent into a cleaning tank for water washing, and then into a copper layer passivation tank.

[0056] (6) copper layer passivation

[0057] The copper-aluminum composite foil after water washing is subjected to copper layer passivation in the copper layer passivation solution in the copper layer passivation tank. The process parameters of the copper layer passivation solution in the copper layer passivation process are shown in Table 4:

[0058] Table 4

[0059]

[0060] (7) water washing - oven air cooling - winding

[0061] The copper-aluminum composite foil after copper layer passivation is sent into a cleaning tank for water washing, then baked in an oven at 120°C, then air-cooled to reduce the material temperature, and finally wound to obtain the surface-modified copper-aluminum composite foil.

[0062] The copper-aluminum composite foil after the above surface treatment is subjected to performance testing, including surface daoyin value testing, anti-peeling strength testing, normal temperature storage testing and high temperature resistance testing, and the copper-aluminum composite foil before surface treatment is taken as a comparison, and the results are as follows:

[0063] The copper-aluminum composite foil subjected to surface treatment by the surface treatment method of the application has a surface daoyin value of 42, which is higher than that of the copper-aluminum composite foil before surface treatment, which has a surface daoyin value of ≤36.​

[0064] The copper-aluminum composite foil treated by the surface treatment method has a peel strength of 0.86 N / mm, which is higher than that of the copper-aluminum composite foil before the surface treatment, i.e., 0.6 N / mm.

[0065] The copper-aluminum composite foil treated by the surface treatment method is not oxidized and discolored on the copper surface after being stored at room temperature for 200 days.

[0066] The copper-aluminum composite foil treated by the surface treatment method is not oxidized and discolored on the copper surface after being baked at 180°C for 1 hour.

[0067] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered by the protection scope of the present application.

Claims

1. A surface treatment method for copper-aluminum composite foil, characterized in that: The following steps are involved: After the copper-aluminum composite foil to be surface-treated is subjected to carbon-hydrogen degreasing, copper plating and thickening, copper layer roughening and copper layer passivation are sequentially performed on one side of the copper layer of the copper-aluminum composite foil; The temperature for roughening the copper layer is 15° C. to 18° C., and the time for roughening the copper layer is 8s to 12s; The copper layer roughening is performed in a copper layer roughening solution, and the copper layer roughening solution comprises: Copper ion: 10g / L~15g / L; Sulfuric acid: 210g / L~220g / L; Chloride ion: 20ppm~30ppm; Potassium dichromate: 0.3g / L~0.6g / L; Nickel sulfate: 0.8g / L~1.2g / L.

2. The surface treatment method according to claim 1, characterized in that The copper-aluminum composite foil to be surface treated is subjected to carbon-hydrogen degreasing in a light carbon-hydrogen degreasing cleaning material; The density of the light hydrocarbon degreasing cleaning material at 20°C is 0.725 g / cm 3 ~0.745g / cm 3 ; The flash point of the light hydrocarbon degreasing cleaning material is ≥40°C; The withstand voltage of the light hydrocarbon degreasing cleaning material is ≥20kV; The distillation range of 98% distillate of the light hydrocarbon degreasing cleaning material is 160°C to 200°C.

3. The surface treatment method according to claim 2, characterized in that The light hydrocarbon degreasing cleaning material is specifically SKH-620 hydrocarbon cleaning agent.

4. The surface treatment method according to claim 1, characterized in that The copper layer passivation is carried out in a copper layer passivation solution, and the copper layer passivation solution comprises: Zinc sulfate: 3g / L~3.5g / L; Chromic anhydride: 0.5g / L~0.8g / L; Sodium hydroxide: 20g / L~25g / L.

5. The surface treatment method according to claim 4, characterized in that: The passivation temperature of the copper layer is 35° C. to 40° C., and the passivation time of the copper layer is 8s to 12s.

6. The surface treatment method according to claim 1, characterized in that: The thickness of the copper layer of the copper-aluminum composite foil after copper plating is 1 μm to 4 μm.

7. The surface treatment method according to claim 1, characterized in that: The copper plating thickening is carried out in a copper plating thickening solution, and the copper plating thickening solution comprises: Copper ion: 20g / L~25g / L; Sulfuric acid: 130g / L~160g / L; Leveling agent: 4mL / L~6mL / L; Brightener: 4mL / L~6mL / L.

8. The surface treatment method according to claim 7, characterized in that: The temperature of the copper plating thickening is 24°C to 30°C.

9. The surface treatment method according to claim 1, characterized in that: The copper-aluminum composite foil to be surface treated comprises: Aluminum layer; An alloy layer is provided on the aluminum layer, wherein the alloy layer is a copper-chromium alloy layer, a copper-nickel alloy layer, a nickel-zinc alloy layer or a nickel-chromium alloy layer; A copper layer is disposed on the alloy layer.

10. A surface-treated copper-aluminum composite foil, characterized in that: The copper-aluminum composite foil is obtained by surface treating the copper-aluminum composite foil to be surface treated by the surface treatment method described in any one of claims 1 to 9.

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