A method for preparing nickel-containing interface copper-aluminum composite strip

Abstract

This invention belongs to the field of copper-aluminum composite strips, specifically relating to a method for preparing a nickel-containing interface copper-aluminum composite strip. The method involves electroplating a nickel layer onto the composite surface of a copper strip, then heating the nickel-plated copper strip, and finally rolling the heated copper strip and aluminum strip together. During this rolling process, semi-molten aluminum forms at the composite interface, resulting in a nickel-containing interface copper-aluminum composite strip. This invention, by nickel-plating and heating the copper strip, and then combining it with an aluminum strip while still heated, ensures the flatness and uniformity of the interface, ultimately producing a high-performance copper-aluminum composite strip with a nickel-containing interface. The aluminum at the bonding surface is heated and pressurized during rolling, creating a semi-molten aluminum structure at the interface.

Description

Technical Field

[0001] This invention belongs to the field of copper-aluminum composite strips, and specifically relates to a method for preparing a nickel-interface copper-aluminum composite strip. Background Technology

[0002] Copper and aluminum are two important non-ferrous metals. Copper-aluminum layered composite materials, prepared through certain composite methods, can simultaneously possess the excellent thermal and electrical conductivity of both copper and aluminum. These composite materials offer lower costs, achieve lightweighting, and enable efficient bonding of copper and aluminum. They have already found widespread application in fields such as machinery, communications, power, and transportation.

[0003] Common methods for preparing copper-aluminum layered composites include explosive bonding, casting bonding, and rolling bonding. Explosive bonding can achieve high-strength composites, but the process is highly polluting and production sites are limited. Casting bonding can achieve composites of various shapes, but the interface layer is too thick, resulting in poor performance. Rolling bonding enables continuous production, but the process is complex, product performance uniformity is difficult to control, and the dimensional requirements of the composite material are high. While these bonding methods each have their advantages, their complex processes, high energy consumption, high pollution, and poor product performance limit their further application and promotion.

[0004] Chinese invention patent CN110721999B discloses a copper-aluminum composite strip with an added nickel grid layer and its continuous production method. The copper-aluminum composite strip consists of three metal layers: two outer layers are a copper substrate and an aluminum cladding, and the middle layer is a nickel grid layer electroplated on the surface of the copper substrate. During production, a nickel grid layer of appropriate thickness is first electroplated onto the surface of the copper substrate; then, the copper substrate with the nickel grid layer and the aluminum cladding are simultaneously placed in a composite rolling mill, and the composite is completed through a single-pass large deformation (controlling the deformation amount to 55-70%); finally, the composite strip is placed in an online annealing furnace for heat treatment (the heat treatment temperature needs to reach 450-540℃), resulting in a copper-aluminum composite strip with high composite strength and excellent surface quality.

[0005] The manufacturing process of the copper-aluminum composite strip, as demonstrated by comparative experiments, necessitates a single-pass large deformation of over 55% and heat treatment at temperatures above 450℃ to achieve a metallurgical bond at the composite interface; otherwise, effective copper-aluminum composite bonding cannot be achieved. This significant deformation directly impacts the uniformity of the copper-aluminum composite strip, while the requirement for heat treatment above 450℃ after composite rolling further complicates the process, hindering the compact and continuous production of copper-aluminum composite strips. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing nickel-containing interface copper-aluminum composite strips that eliminates the need for large deformation rolling and subsequent heat treatment at temperatures above 450°C, effectively solving the problems of poor uniformity and complex production processes in copper-aluminum composite strips prepared by existing methods.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0008] A method for preparing a nickel-containing interface copper-aluminum composite strip includes the following steps: electroplating a nickel layer on the composite surface of a copper strip, heating the nickel-plated copper strip, and rolling the heated copper strip and aluminum strip together. During the rolling process, semi-molten aluminum is formed at the composite interface, and a nickel-containing interface copper-aluminum composite strip is obtained after rolling.

[0009] The present invention discloses a method for preparing a nickel-containing interface copper-aluminum composite strip. This method involves nickel plating and heating a copper strip, followed by hot bonding with an aluminum strip. During rolling, the aluminum at the bonding surface is heated and pressurized, generating a semi-molten aluminum structure at the interface. This ensures the flatness and uniformity of the interface of the copper-aluminum composite strip, ultimately producing a high-performance copper-aluminum composite strip with a nickel-containing interface. This method eliminates the need for large deformation during rolling, facilitating the production of flat and uniform products. Furthermore, it achieves interfacial bonding without requiring heat treatment above 450°C after rolling. The method offers significant advantages such as high composite strength, strong heat resistance, compact manufacturing process, and energy efficiency.

[0010] This method enables continuous, automated, and efficient production, and can laminate different types, quantities, and widths of copper strips in one step according to product requirements, while also laminating different types and thicknesses of aluminum sheets.

[0011] Preferably, the heating temperature is 670–710°C. Setting the heating temperature to 670–710°C allows for effective heating of the aluminum on the bonding surface, resulting in the formation of semi-molten aluminum at the bonding interface.

[0012] Preferably, the thickness of the nickel layer is 3–5 μm. Controlling the electroplated nickel layer to this thickness not only prevents oxidation of the copper composite surface but also achieves higher composite strength.

[0013] The purpose of the rolling composite process in this invention is to achieve flatness and interface uniformity in the strip without using a large rolling force to achieve large deformation and interface diffusion. Preferably, the deformation rate of the rolling composite process is 10-20%. By controlling the deformation rate within this range, copper-aluminum composite strips with high composite strength and high heat resistance can be obtained.

[0014] Preferably, the heating is online heating, and the rolling process is continuous. This continuous production method aligns with industrial production practices, and its compact production flow further enhances enterprise production efficiency. Attached Figure Description

[0015] Figure 1 A schematic diagram of the apparatus for preparing the nickel-containing interface copper-aluminum composite plate and strip of the present invention;

[0016] Figure 2 This is a microscopic interface diagram of the nickel-containing copper-aluminum composite strip of Embodiment 1 of the present invention.

[0017] Among them, 1-copper plate and strip; 2-surface treatment device; 3-nickel electroplating device; 4-online heating device; 5-aluminum plate and strip; 6-rolling mill. Detailed Implementation

[0018] In response to the problems of numerous steps, poor flexibility, low efficiency, and high energy consumption in the existing copper-aluminum composite strip production process, the nickel-containing copper-aluminum layered composite material obtained by the preparation method of this invention has outstanding advantages such as high composite strength, strong heat resistance, compact preparation process, and energy efficiency, which can effectively solve the difficulties and pain points of the existing methods.

[0019] The method for preparing the nickel-containing interface copper-aluminum composite strip of the present invention is illustrated in the schematic diagram of the apparatus used. Figure 1 As shown, copper strip 1 passes through surface treatment device 2, nickel electroplating device 3, and online heating device 4 in sequence, and then enters rolling mill 6 with aluminum strip 5 that has passed through surface treatment device 2 for rolling composite. After rolling composite, a nickel-containing interface copper-aluminum composite strip is obtained, which specifically includes the following steps:

[0020] (1) Surface treatment

[0021] Surface treatment involves polishing and dust removal of the composite surface of the copper and aluminum sheets. Polishing removes the surface oxide layer; continuous polishing with sandpaper is used until the metallic luster is exposed. This polishing process ensures the composite surface of the copper and aluminum sheets is clean and active, preparing it for subsequent processes.

[0022] Depending on actual production needs, the thickness of copper strip can range from 1 to 5 mm, and the thickness of aluminum strip can range from 5 to 10 mm.

[0023] (2) Electroplated nickel layer

[0024] A nickel layer is electroplated onto the composite surface of the copper strip using a brush plating method, with the nickel layer thickness controlled between 3 and 5 micrometers. This nickel plating prevents oxidation of the copper composite surface and effectively inhibits excessive thickness growth of the interface layer during the composite process, thereby improving the bonding strength of the copper-aluminum interface.

[0025] (3) Online heating

[0026] This step involves online heating of the nickel-plated copper plate at a temperature of 670-710℃ to prepare for the copper-aluminum interface to form a semi-molten aluminum.

[0027] (4) Rolling

[0028] Copper and aluminum strips, after being heated online, are rolled together. During the rolling process, the aluminum at the bonding surface is heated and pressurized to produce a semi-molten aluminum structure at the interface, ensuring the flatness of the copper-aluminum composite strip and the uniformity of the interface, and finally preparing a high-performance copper-aluminum composite plate with nickel at the interface.

[0029] The implementation process of the present invention will be described in detail below with reference to specific embodiments.

[0030] I. Specific embodiments of the preparation method of the nickel-containing interface copper-aluminum composite plate and strip of the present invention are as follows:

[0031] Example 1

[0032] The preparation method of the nickel-containing interface copper-aluminum composite strip in this embodiment includes the following steps:

[0033] (1) Grind and dust-removing pretreatment is performed on the composite surface of copper and aluminum plates and strips.

[0034] In this embodiment, the copper strip has a thickness of 2.5 mm and the aluminum strip has a thickness of 6 mm.

[0035] (2) A nickel layer is electroplated on the composite surface of the copper strip using a brush plating method, and the thickness of the nickel layer is controlled to be 3 to 5 micrometers.

[0036] (3) The nickel-plated copper plate is heated online at a temperature of 680℃.

[0037] (4) The copper-aluminum plate and strip are introduced into the rolling mill for rolling. During the rolling process, the aluminum at the interface is heated and pressurized to produce a semi-molten aluminum structure at the interface, and finally a high-performance copper-aluminum composite plate and strip with nickel at the interface is prepared.

[0038] In this embodiment, the deformation during rolling is 16%.

[0039] Example 2

[0040] The preparation method of the nickel-containing interface copper-aluminum composite strip in this embodiment includes the following steps:

[0041] (1) Grind and dust-removing pretreatment is performed on the composite surface of copper and aluminum plates and strips.

[0042] In this embodiment, the thickness of the copper strip is 2mm and the thickness of the aluminum strip is 5mm.

[0043] (2) A nickel layer is electroplated on the composite surface of the copper strip using a brush plating method, and the thickness of the nickel layer is controlled to be 3 to 5 micrometers.

[0044] (3) The nickel-plated copper plate is heated online at a temperature of 690℃.

[0045] (4) The copper-aluminum plate and strip are introduced into the rolling mill for rolling. During the rolling process, the aluminum at the interface is heated and pressurized to produce a semi-molten aluminum structure at the interface, and finally a high-performance copper-aluminum composite plate and strip with nickel at the interface is prepared.

[0046] In this embodiment, the deformation during rolling is 12%.

[0047] Example 3

[0048] The preparation method of the nickel-containing interface copper-aluminum composite strip in this embodiment includes the following steps:

[0049] (1) Grind and dust-removing pretreatment is performed on the composite surface of copper and aluminum plates and strips.

[0050] In this embodiment, the thickness of the copper strip is 1.5 mm, and the thickness of the aluminum strip is 5 mm.

[0051] (2) A nickel layer is electroplated on the composite surface of the copper strip using a brush plating method, and the thickness of the nickel layer is controlled to be 3 to 5 micrometers.

[0052] (3) The nickel-plated copper plate is heated online at a temperature of 710℃.

[0053] (4) The copper-aluminum plate and strip are introduced into the rolling mill for rolling. During the rolling process, the aluminum at the interface is heated and pressurized to produce a semi-molten aluminum structure at the interface, and finally a high-performance copper-aluminum composite plate and strip with nickel at the interface is prepared.

[0054] In this embodiment, the deformation during rolling is 10%.

[0055] II. Experimental Examples

[0056] Experimental Example 1

[0057] This experimental example involves microscopic analysis of the interface of the nickel-containing copper-aluminum composite strip from Example 1. The results are as follows: Figure 2 As shown.

[0058] Depend on Figure 2 It can be seen that the copper-aluminum interface consists of a nickel plating layer and a solid solution interface, exhibiting a typical metallurgical bonding state.

[0059] Experiment Example 2

[0060] Peel strength and heat resistance tests were performed on the copper-aluminum composite plates of each embodiment. The specific test methods were in accordance with the provisions of GB / T32468-2015 Copper-Aluminum Composite Plates and Strips.

[0061] Peel strength tests were conducted on the copper-aluminum composite panels of each embodiment to detect the bonding strength of their interfaces. The results showed that the peel strength of the composite panels was ≥24 N / mm, which is more than twice the peel strength required by the national standard.

[0062] The copper-aluminum composite panels of each embodiment were subjected to a heat resistance test at 120°C for 20 hours. After the test, the peel strength of the copper-aluminum composite panels was ≥18N / mm.

[0063] Based on the above experimental results, it can be seen that the copper-aluminum composite strip prepared by the method of the present invention exhibits high interfacial bonding strength and heat resistance, and excellent overall performance.

Claims

1. A method for preparing a nickel-containing interface copper-aluminum composite plate / strip, characterized in that, Includes the following steps: A nickel layer is electroplated on the composite surface of the copper strip, and then the nickel-plated copper strip is heated. The heated copper strip and aluminum strip are rolled together. During the rolling process, semi-molten aluminum is formed at the composite interface. After rolling, a nickel-containing interface copper-aluminum composite strip is obtained. The heating temperature is 670~710℃, and the deformation rate of the rolling process is 10~16%.

2. The method for preparing nickel-containing interface copper-aluminum composite strip as described in claim 1, characterized in that, The heating temperature is 680~710℃.

3. The method for preparing nickel-containing interface copper-aluminum composite strips as described in claim 1, characterized in that, The thickness of the nickel layer is 3~5μm.

4. The method for preparing nickel-containing interface copper-aluminum composite strips as described in any one of claims 1 to 3, characterized in that, The copper strip has a thickness of 1–5 mm, and the aluminum strip has a thickness of 5–10 mm.

5. The method for preparing nickel-containing interface copper-aluminum composite strip as described in claim 4, characterized in that, The heating is conducted online, and the rolling process is carried out continuously.

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