EP-4552768-B1 - PROCESS FOR COPPER-ALUMINUM COMPOSITE BOARD PREPARED BY MEANS OF MOLTEN ALUMINUM CONTINUOUS CASTING

EP4552768B1EP 4552768 B1EP4552768 B1EP 4552768B1EP-4552768-B1

Inventors

LV, Jiangang
WANG, Fenglin
YANG, Weifu
HUANG, Yufan
ZHAI, Xuemin
FENG, Haiquan

Dates

Publication Date: 20260513
Application Date: 20241209

Claims (5)

A process of a copper-aluminum composite plate material prepared by aluminum liquid continuous casting, comprising the following steps: S1, smelting: heating an aluminum ingot to 700-800°C and smelting for 1-3 h; S2, standing: degassing aluminum liquid smelted in step S1, and keeping the temperature and standing for 10-30 min; adding Cu@Si@Al Janus nanosheets in an amount of 5-7 wt% of the aluminum liquid before degassing treatment, wherein a preparation method of the Cu@Si@Al Janus nanosheets is as follows: T1, preparation of SiO 2 hollow nanospheres: dissolving ethyl orthosilicate in an organic solvent to prepare an oil phase; dissolving an emulsifier in water to prepare a water phase; dropwise adding the water phase into the oil phase, emulsifying, adjusting a pH value of the solution to 10-11, performing heating and stirring reaction, centrifuging, washing, drying and calcining to prepare SiO 2 hollow nanospheres; T2, ball milling: performing ball milling on the SiO 2 hollow nanospheres prepared in step T1 to prepare SiO 2 nanosheets; T3, modification: adding the SiO 2 nanosheets prepared in step T2 into ethanol, adding a silane coupling agent, performing heating and stirring reaction, centrifuging, washing and drying to prepare modified SiO 2 nanosheets; T4, preparation of CuO@SiO 2 @Al 2 O 3 nanosheets: dissolving aluminum isopropoxide in dichloromethane, standing, adding the modified SiO 2 nanosheets prepared in step T3, which float on the interface, dropwise adding an aqueous solution containing a copper salt, then adding citric acid, performing standing reaction, centrifuging, washing, drying and calcining to prepare CuO@SiO 2 @Al 2 O 3 nanosheets; and T5, reduction: mixing the CuO@SiO 2 @Al 2 O 3 nanosheets prepared in step T4 with magnesium powder, performing heating reduction reaction, and then performing hydrogen reduction reaction to prepare the Cu@Si@Al Janus nanosheets; wherein in step T1, a mass ratio of the ethyl orthosilicate, organic solvent, emulsifier and water is 12-15:100:0.5-1:30-50, the emulsifier is selected from at least one of Tween-20, Tween-40, Tween-60 and Tween-80, a temperature of the heating and stirring reaction is 50-60°C for 10-12 h, and a temperature of the calcining is 300-500°C for 1-3 h; time of the ball milling in step T2 is 2-4 h; and in step T3, a mass ratio of the SiO 2 nanosheets to the silane coupling agent is 100:22-25, the silane coupling agent is a silane coupling agent with amino groups and is selected from at least one of KH550, KH602 and KH792, and a temperature of the heating and stirring reaction is 40-50°C for 0.5-1 h; wherein in step T4, a mass ratio of the modified SiO 2 nanosheets, aluminum isopropoxide, copper salt and citric acid is 50:12-15:7-12:3-5, time of the standing reaction is 30-50 min, a temperature of the calcining is 500-700°C for 1-3 h, and the copper salt is selected from at least one of copper chloride, copper sulfate and copper nitrate; and in step T5, a mass ratio of the CuO@SiO 2 @Al 2 O 3 nanosheets to the magnesium powder is 100:7-12, a temperature of the heating reduction reaction is 700-800°C for 0.5-1 h, a temperature of the hydrogen reduction reaction is 600-800°C for 1-2 h, and a ventilation rate of hydrogen is 20-30 mL/min, S3, copper strip pretreatment: texturing the copper strip, and then cleaning; S4, copper strip heating: heating the pretreated copper strip obtained in step S3 to 200-650°C; S5, continuous casting: under the protection of inert gas, continuously casting the aluminum liquid treated in step S2 on the copper strip treated in step S4, performing quenching crystallization on a copper-aluminum composite material, and performing oxygen-free continuous casting; and S6, continuous rolling: rolling the copper-aluminum composite material continuously cast in step S5 to obtain the copper-aluminum composite plate material prepared by aluminum liquid continuous casting.
The process according to claim 1, wherein the texturing in step S3 comprises mechanical texturing, chemical texturing or laser texturing, the mechanical texturing is texturing with a steel brush or an abrasive belt, and the cleaning is ultrasonic cleaning or laser cleaning.
The process according to claim 1, wherein in step S5, a casting speed is 200-1200 mm/min; a casting width is 10-100 mm; a casting thickness is 3-20 mm, a cooling rate of the quenching crystallization is 100-150°C/min, and the specific method is as follows: under the protection of inert gas, enabling the copper strip treated in step S4 to continuously pass through a continuous casting device and a crystallizer, continuously casting the aluminum liquid on the copper strip through a casting system, performing quenching crystallization on the copper-aluminum composite material through the crystallizer, and performing oxygen-free continuous casting.
The process according to claim 1, wherein in step S6, a thickness of the copper-aluminum composite plate material prepared by aluminum liquid continuous casting is 2-12 mm, a rolling pressure is 5000-5000000 N, a rolling speed is 300-1500 mm/min, and a rolling tension is 10000-200000 N.
The process according to claim 1, wherein after the cleaning in step S3, the surface is coated with a layer of ethylene glycol dimethyl ether solution of 11-mercapto undecanoic acid with a concentration of 7-12 wt%.

Description

TECHNICAL FIELD The present invention relates to the field of composite plate material technologies, in particular to a process for a copper-aluminum composite plate material prepared by aluminum liquid continuous casting. BACKGROUND ART Copper and aluminum are important nonferrous metals. Copper has good electrical conductivity, thermal conductivity and corrosion resistance, and aluminum has good electrical conductivity and thermal conductivity. Compared with aluminum, copper resources are in short supply, aluminum resources are abundant, and the specific weight of aluminum is small and the price thereof is low. An aluminum-copper composite metal plate strip is a bimetal formed by coating copper with aluminum as a matrix outer layer. It is a new conductor material and decorative material that combines high-quality conductivity and low-cost resources of aluminum with high chemical stability and lower contact resistance of copper. The aluminum-copper composite metal plate strip integrates respective advantages of copper and aluminum. The aluminum-copper composite metal plate strip instead of a copper plate strip is widely used in high-tech fields such as military industry, aerospace, electronic computers and electronic devices, as well as electric power, high and low voltage electrical appliances, automation and construction industries, and is the research focus of current metal materials. In international standards, the composite strength of a copper-aluminum composite material is ≥12 kgf/cm, and the requirement of existing lithium batteries for the composite strength of the copper-aluminum composite material is ≥15 kgf/cm. With the continuous development of new energy technology, the lithium batteries are core energy storage devices in new energy, and the copper-aluminum composite material is a core component material of the lithium battery. Therefore, lithium battery manufacturers put forward higher requirements for the strength of the copper-aluminum composite material. At present, production methods of the copper-aluminum composite plate strip mainly include solid-solid composite methods such as rolled composite, explosive composite, extrusion-drawing composite and diffusion welding composite, and liquid-solid composite methods such as core-filled continuous casting and double-crystallizer continuous casting. The process of the solid-solid composite methods is generally backward, with low yield and unstable quality, and is not suitable for continuous large-scale production. Therefore, the liquid-solid composite methods have become the focus of research. However, the liquid-solid composite methods directly composite aluminum liquid with a copper plate, which will generate a very thick bonding interface layer. The thicker the bonding interface layer, the more intermetallic compounds and the lower the strength of the composite plate strip. Therefore, the bonding interface layer formed by directly compositing the aluminum liquid with the copper plate is thicker and the strength of the composite plate is lower, which cannot meet the requirements of use. The Chinese invention patent CN101758071B discloses a production method of an aluminum-copper composite metal plate strip, which prepares the copper-aluminum composite plate strip by adopting an oxygen-free continuous casting-rolling method. This method needs to perform on-line polishing until there is no oxide layer before copper-aluminum bonding, the process is relatively complicated, and the copper-aluminum bonding strength is lower (about 100 MPa). CN115338375A discloses a production method of a copper-aluminum composite plate strip material, which comprises the following steps of: heating an oxygen-free copper plate strip which is not passivated on line in molten aluminum; the prepared semi-solid aluminum is in contact with a copper plate strip, anaerobic continuous cast rolling is carried out, the copper-aluminum composite plate strip material is obtained. SUMMARY OF THE INVENTION An objective of the present invention is to provide a process for a copper-aluminum composite plate material prepared by aluminum liquid continuous casting, which can be used for preparing a pole of a new energy battery. Through the process of continuous casting and multiple rolling, the wettability of an aluminum-copper metal interface is improved, and the prepared composite plate material has high bonding strength, small interface thickness, high composite strength, good mechanical properties, simple preparation method, low cost, high efficiency and broad application prospects. The technical solution of the present invention is realized in such a way, which is set out in the appended set of claims. The present invention has the following beneficial effects: When the wettability between metal matrixes is poorer, interface defects such as interface pores and cracks will be generated between the metal matrixes in a preparation process, which will lead to brittle phase compounds