Preparation method of strong interface heterogeneous metal composite foil

Abstract

The invention belongs to the technical field of metal structure composite materials, and particularly relates to a preparation method of a strong interface heterogeneous metal composite foil. According to the preparation method of the strong interface heterogeneous metal composite foil, a copper plate serves as a mold core and is placed in the center of a cold isostatic pressing square sheath, the two sides of the copper plate are filled with nickel powder, the sheath is packaged in a vacuumizing mode, a nickel-copper-nickel composite plate blank is obtained through cold isostatic pressing forming and vacuum sintering, and the nickel-copper-nickel composite foil is obtained through hot rolling and cold rolling. The nickel powder and the copper plate are subjected to vacuum diffusion welding, a nickel-copper interface reaches atomic-level strong metallurgical bonding, residual gas is removed in vacuum, bubbles of rolled foil are prevented, and the material yield is greatly increased. The nickel powder sintered body is small in deformation resistance, rolling force can be effectively reduced, energy consumption is reduced, production efficiency is improved, and the method has extremely important application prospects in the field of new energy battery pole pieces.

Description

Technical Field

[0001] The invention belongs to the technical field of metal structure composite materials, and particularly relates to a method for preparing a strong-interface heterogeneous metal composite foil. Technical Background

[0002] Heterogeneous metal layered composite materials are a new type of structural and functional material. They use composite technology to firmly bond metal components with different physical, mechanical and other properties at the interface, so that they have the excellent properties of each component metal. Nickel-copper double-layer metal composite material is a new energy battery electrode material with excellent comprehensive performance. It can currently be produced through hot-rolled composite technology. With the further improvement of the comprehensive performance requirements of new energy batteries, nickel-copper-nickel three-layer heterogeneous metal composite materials have become a development trend. Traditional hot-rolled composite three-layer nickel-copper-nickel heterogeneous metal composite materials are prone to defects such as weak interface bonding and bubbles during processing, resulting in a serious decrease in the yield rate. Although nickel plating can be obtained on both sides of the copper strip through electroplating technology, the nickel layer is too thin and does not meet the use requirements. At the same time, electroplating technology has a relatively serious environmental pollution and high energy consumption, which does not meet the national dual carbon and energy conservation and environmental protection strategic requirements. Summary of the Invention

[0003] The present invention aims to overcome the shortcomings of the prior art by providing a method for preparing heterogeneous metal composite foils with strong interfaces. The metal composite foils produced by this method exhibit good interface bonding, are easily formed, and are free of air bubble defects. This method not only addresses the problem of interlayer cracking in conventional composite rolling processes, but also eliminates defects such as air bubbles, thereby improving the yield rate.

[0004] To achieve the above technical objectives, the technical solution adopted in the embodiment of the present invention is: a method for preparing a strong interface heterogeneous metal composite foil, comprising the following steps: (1) Preparation of nickel-copper-nickel composite green body: A copper plate is used as a core, placed in the center of a cold isostatically pressed square package, nickel powder is filled on both sides of the copper plate, the package is vacuum-sealed, and a nickel-copper-nickel three-layer composite green body is obtained by cold isostatic pressing; (2) Sintering of nickel-copper-nickel composite green body: Place the composite green body in a vacuum sintering furnace and evacuate to 10 -1 ~10 -3 Pa, and sintered at 850-1050 °C for 1-5 h to obtain a nickel-copper-nickel composite sintered blank; (3) Preparation of nickel-copper-nickel composite foil: The prepared nickel-copper-nickel composite sintered billet is preheated at 800-1000 °C for 1-3 h, hot-rolled and bright annealed, and then cold-rolled for multiple passes to obtain nickel-copper-nickel composite foil.

[0005] Furthermore, in step (1), the surface of the copper plate is sandblasted, and the surface roughness of the copper plate after sandblasting is 20-75 μm.

[0006] Furthermore, the material of the cold isostatically pressed square sheath in step (1) is one of rubber, silicone and polyurethane.

[0007] Furthermore, the average particle size of the nickel powder in step (1) is 1-100 μm.

[0008] Furthermore, the vacuuming time in step (1) is 0.5 to 5 h.

[0009] Furthermore, the cold isostatic pressing pressure in step (1) is 100-500 MPa, and the holding time is 1-10 min.

[0010] Furthermore, the nickel layers on both sides of the nickel-copper-nickel three-layer composite green body in step (1) are symmetrically arranged, the nickel layers on both sides have the same mass, and the mass ratio of the single nickel layer to the copper plate is 1:1~5:1.

[0011] Furthermore, the relative density of the nickel layer in the nickel-copper-nickel composite sintered blank in step (2) is 95% to 99.5%.

[0012] Furthermore, the preheating atmosphere of the nickel-copper-nickel composite sintered blank in step (3) is one or more of hydrogen, nitrogen, argon, decomposed ammonia and natural gas.

[0013] Furthermore, the thickness of the nickel-copper-nickel composite foil in step (3) is 0.05-0.5 mm.

[0014] Compared with the prior art, the technical solution provided by the embodiment of the present invention has the following beneficial effects: 1. The present invention uses vacuum diffusion welding between nickel powder and copper plate to achieve strong metallurgical bonding at the atomic level at the nickel-copper interface, with high interface bonding strength; vacuum sintering can remove residual gas, prevent the generation of bubbles in the rolled foil, and greatly improve the material yield.

[0015] 2. The nickel powder sintered body of the present invention has low deformation resistance, can effectively reduce rolling force, has low energy consumption, high production efficiency, low cost, can achieve continuous production, and has important application prospects in the field of new energy battery pole pieces. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Example 1 A method for preparing a strong interface heterogeneous metal composite foil comprises the following steps: (1) Preparation of nickel-copper-nickel composite green body: A copper plate with a thickness of 50 mm was used as the core, and the surface of the copper plate was sandblasted to a surface roughness of 75 μm. The sandblasted copper plate was placed in the center of a cold isostatically pressed square rubber sleeve, and nickel powder with an average particle size of 100 μm was filled on both sides of the copper plate. After vacuuming for 0.5 h, the sleeve was sealed and the nickel-copper-nickel three-layer composite green body was obtained by cold isostatic pressing. The cold isostatic pressing pressure was 500 MPa and the holding time was 1 min. (2) Nickel-copper-nickel composite green body sintering: Place the above nickel-copper-nickel three-layer composite green body in a vacuum sintering furnace and evacuate to 10 -1 Pa, and the nickel-copper-nickel composite sintered blank was obtained by sintering at 1050 °C for 1 h. The relative density of the nickel layer in the sintered blank was 95%. (3) Preparation of nickel-copper-nickel composite foil: The prepared nickel-copper-nickel composite sintered billet was placed in a hydrogen atmosphere, preheated at 1000°C for 1 h, hot-rolled, bright annealed, and then cold-rolled multiple times to obtain a nickel-copper-nickel composite foil with a thickness of 0.5 mm. The thicknesses of the nickel layer, copper layer, and nickel layer in the nickel-copper-nickel composite foil were 0.2 mm, 0.1 mm, and 0.2 mm, respectively. Mechanical property tests showed that the tensile strength of the nickel-copper-nickel composite foil reached 465 MPa, and the interlayer bonding was tight, meeting the requirements of new energy battery electrodes.

[0018] Example 2 A method for preparing a strong interface heterogeneous metal composite foil comprises the following steps: (1) Preparation of nickel-copper-nickel composite green body: A copper plate with a thickness of 30 mm was used as the core, and the surface of the copper plate was sandblasted to a surface roughness of 20 μm. The sandblasted copper plate was placed in the center of a cold isostatically pressed square silicone sleeve, and nickel powder with an average particle size of 1 μm was filled on both sides of the copper plate. After vacuuming for 5 h, the sleeve was sealed and the nickel-copper-nickel three-layer composite green body was obtained by cold isostatic pressing. The cold isostatic pressing pressure was 100 MPa and the holding time was 10 min. (2) Nickel-copper-nickel composite green body sintering: Place the above nickel-copper-nickel three-layer composite green body in a vacuum sintering furnace and evacuate to 10 -3 Pa, and sintered at 850 °C for 5 h to obtain a nickel-copper-nickel composite sintered blank, in which the relative density of the nickel layer is 99.5%; (3) Preparation of nickel-copper-nickel composite foil: The prepared nickel-copper-nickel composite sintered billet was placed in a natural gas atmosphere, preheated at 800°C for 3 h, hot-rolled, bright annealed, and then cold-rolled multiple times to obtain a nickel-copper-nickel composite foil with a thickness of 0.3 mm. The thicknesses of the nickel layer, copper layer, and nickel layer in the nickel-copper-nickel composite foil were 0.1 mm, 0.1 mm, and 0.1 mm, respectively. Mechanical property tests showed that the tensile strength of the nickel-copper-nickel composite foil reached 512 MPa, and the interlayer bonding was tight, meeting the requirements of new energy battery electrodes.

[0019] Example 3 A method for preparing a strong interface heterogeneous metal composite foil comprises the following steps: (1) Preparation of nickel-copper-nickel composite green body: A copper plate with a thickness of 30 mm was used as the core, and the surface of the copper plate was sandblasted to a surface roughness of 45 μm. The sandblasted copper plate was placed in the center of a cold isostatically pressed square silicone sleeve, and nickel powder with an average particle size of 8 μm was filled on both sides of the copper plate. After vacuuming for 3 h, the sleeve was sealed and the nickel-copper-nickel three-layer composite green body was obtained by cold isostatic pressing. The cold isostatic pressing pressure was 200 MPa and the holding time was 3 min. (2) Nickel-copper-nickel composite green body sintering: Place the above nickel-copper-nickel three-layer composite green body in a vacuum sintering furnace and evacuate to 10 -2 Pa, and sintered at 950 °C for 3 h to obtain a nickel-copper-nickel composite sintered blank, in which the relative density of the nickel layer is 98.5%; (3) Preparation of nickel-copper-nickel composite foil: The prepared nickel-copper-nickel composite sintered billet was placed in a nitrogen atmosphere, preheated at 900°C for 2 h, hot-rolled, bright annealed, and then cold-rolled multiple times to obtain a nickel-copper-nickel composite foil with a thickness of 0.05 mm. The thicknesses of the nickel layer, copper layer, and nickel layer in the nickel-copper-nickel composite foil were 0.02 mm, 0.01 mm, and 0.02 mm, respectively. Mechanical property tests showed that the tensile strength of the nickel-copper-nickel composite foil reached 648 MPa, and the interlayer bonding was tight, meeting the requirements of new energy battery electrodes.

[0020] The present invention uses a copper plate as a core, places it in the center of a cold isostatically pressed square package, fills nickel powder on both sides of the copper plate, vacuum-seales the package, obtains a nickel-copper-nickel composite plate blank through cold isostatic pressing and vacuum sintering, and obtains a nickel-copper-nickel composite foil through hot rolling and cold rolling.

[0021] The present invention ensures the formability of nickel-copper-nickel composite green sheets by comprehensively coordinating key parameters such as nickel powder particle size and cold isostatic pressing pressure. If any of these parameters are selected improperly, not only will the nickel layer itself delaminate and crack, but also significant delamination will occur between the nickel layer and the copper plate.

[0022] During the sintering process, the present invention requires strict control of the vacuum level and sintering temperature to produce a nickel-copper-nickel composite foil with the tensile strength required for new energy battery electrodes. Too low a vacuum level prevents the removal of residual gas; too low a sintering temperature results in a high degree of residual porosity in the nickel layer, which can easily cause cracks during rolling. Too high a sintering temperature can lead to the formation of a liquid phase between the copper plate and the nickel layer, resulting in severe shrinkage and deformation.

[0023] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a strong interface heterogeneous metal composite foil, characterized in that: The following steps are involved: (1) Preparation of nickel-copper-nickel composite green body: A copper plate is used as a core and placed in the center of a cold isostatic pressing square package. Nickel powder is filled on both sides of the copper plate, and the package is vacuum-sealed to obtain a nickel-copper-nickel three-layer composite green body by cold isostatic pressing. (2) Sintering of nickel-copper-nickel composite green body: Place the composite green body in a vacuum sintering furnace and evacuate to 10 -1 ~10 -3 Pa, and keep the sintering temperature at 850-1050 °C for 1-5 h to obtain a nickel-copper-nickel composite sintered blank; (3) Preparation of nickel-copper-nickel composite foil: The prepared nickel-copper-nickel composite sintered billet is preheated at 800-1000 °C for 1-3 h, bright annealed after hot rolling, and then cold rolled for multiple times to obtain a nickel-copper-nickel composite foil.

2. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: In step (1), the surface of the copper plate is sandblasted, and the surface roughness of the copper plate after sandblasting is 20-75 μm.

3. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The material of the cold isostatically pressed square package in step (1) is one of rubber, silicone and polyurethane.

4. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The average particle size of the nickel powder in step (1) is 1-100 μm.

5. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The vacuuming time in step (1) is 0.5 to 5 h.

6. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The cold isostatic pressing pressure in step (1) is 100-500 MPa, and the holding time is 1-10 min.

7. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: In the nickel-copper-nickel three-layer composite green body described in step (1), the nickel layers on both sides are symmetrically arranged, the nickel layers on both sides have the same mass, and the mass ratio of the single nickel layer to the copper plate is 1:1~5:

1.

8. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The relative density of the nickel layer in the nickel-copper-nickel composite sintered blank in step (2) is 95% to 99.5%.

9. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The preheating atmosphere of the nickel-copper-nickel composite sintered blank in step (3) is one or more of hydrogen, nitrogen, argon, decomposed ammonia and natural gas.

10. The method for preparing a strong interface heterogeneous metal composite foil according to claim 1, characterized in that: The thickness of the nickel-copper-nickel composite foil in step (3) is 0.05-0.5 mm.