High-bonding strength copper-aluminum composite conductive material and preparation method thereof

Abstract

The present invention provides a high-bonding strength copper-aluminum composite conductive material and a preparation method thereof. The high-bonding strength copper-aluminum composite conductive material comprises a clad copper layer and an aluminum core base body; an interatomic bonded metallurgical bonding layer is formed between the clad copper layer and the aluminum core base body; the thickness of the bonding layer ranges from 5 to 35 microns, and the bonding strength of the bonding layer is more than 40 MPa; a copper-aluminum intermetallic compound is dispersedly distributed in the bonding layer; the components of a diffusion layer adjacent to a copper base body are uniform, and the thickness of the diffusion layer is small; and a diffusion layer adjacent to an aluminum base body is of a reticular structure formed by a mixture of two or more components, and the thickness of the diffusion layer is large. According to the high-bonding strength copper-aluminum composite conductive material and the preparation method thereof of the invention, the bonding of copper and aluminum achieves a metallurgical bonding state, the corresponding bonding strength of the bonding of copper and aluminum is more than 40MPa; the thickness of the side copper layer of the copper-aluminum composite conductive material is about 1.6 to 2 times of the thickness of the plane copper layer of the copper-aluminum composite conductive material; the thickness of the side clad copper layer is large enough to meet the requirements of large current impact and heat dissipation; and the elongation rate of the copper-aluminum composite material is greater than 30%. The processing of torsion, spiraling and side bending of the high-bonding strength copper-aluminum composite conductive material in the application of the high-bonding strength copper-aluminum composite conductive material to new fields can be achieved.

Description

technical field [0001] The invention belongs to the technical field of composite materials, and in particular relates to a copper-aluminum composite conductive material with high bonding strength and a preparation method thereof. Background technique [0002] Copper-aluminum composite material, also known as copper-clad aluminum bar, copper-clad aluminum bus bar, is composed of copper on the outer layer and aluminum on the core. In the existing copper-aluminum composite materials, the outer layer copper and the core aluminum are generally combined by mechanical bonding, that is, the so-called copper-clad aluminum. The outer layer copper and the core aluminum are bonded together by pressing force under solid state action. Yes, the bonding strength of the copper-aluminum interface in this bonding method is low, and the separation of copper and aluminum is easy to occur under the action of external force. Observed under a high-power microscope, there is no mutual diffusion lay...

AI Technical Summary

Problems solved by technology

However, the elongation rate of general copper-aluminum composite materials is 3-20%, and it is difficult to meet the processing requirements of torsion, spiral and side bending, and the product surface is prone to orange peel defects after processing, and the copper-aluminum interface is prone to cracking and separation. During the use of defective products, the current density distributed on the surface of the product is extremely uneven, and the current density at the cracked and separated parts is relatively high, resulting in heating or even burning through the separated parts

In addition, galvanic corrosion may also occur between copper and aluminum at the cracked and separated parts, resulting in safety accidents

[0004] As mentioned above, the shortcomings of the existing copper-aluminum composite materials are: ①The bonding performance between copper and aluminum is weak, and the metallurgical bonding state that does not meet the essential requirements of composite materials, and the corresponding bonding strength is also low; ②For flat width Shaped copper-aluminum composite materials, there is a design problem in the distribution of the thickness of the clad copper layer. The thickness of the narrow-side clad copper layer is relatively thin, and the current density is high, which is not enough to support the high current impact, and the narrow-side clad copper layer is prone to heat. Poor heat dissipation; ③The processing performance of the existing copper-aluminum composite materials can only realize the processing of conventional bending, punching, milling, pressing riveting and tapping, etc. way of processing is not yet available

[0006] The above method ① and method ② basically adopt the solid-state bonding method, that is, through plastic deformation, the solid copper and aluminum are mechanically bonded when relying on external pressure. There is no obvious interdiffusion layer between copper and aluminum, and the bonding strength Very low; the process of the above-mentioned method ③ pouring molten aluminum is discontinuous and unstable, which can easily cause burn-through of the copper tube, and the length of one-time pouring is limited, so there are problems of low yield and production efficiency and unstable product performance; the above-mentioned Method ④ There is no report in China. The hydrostatic extrusion technology has been applied in the UK. The manufacturer Bruker uses a large hydrostatic extrusion machine to extrude and deform the copper tube and the core aluminum rod to realize the solid phase combination between copper and aluminum, and then Forming into copper-aluminum composite materials through various molds, this method has high requirements on the equipment used, and cannot be continuously produced, the production efficiency is low, the loss is large, the process requirements are complicated, the manufacturing cost is high, and it is not suitable for mass production; the above method ⑤ The thickness of the electroplating copper layer is limited, and the general electroplating thickness is far lower than the thickness of copper tubes used in other methods, and the copper layer is easy to fall off, which cannot ensure the quality of the product