Laminated strip-shaped self-brazing filler metal for aluminum-copper brazing and preparation method thereof

Abstract

The invention relates to the technical field of brazing materials, in particular to laminated strip-shaped self-brazing filler metal for copper-aluminum brazing and a preparation method thereof. The self-brazing filler metal is of a five-layer laminated strip-shaped structure, the innermost layer is a pure nickel layer, the two outer sides of the pure nickel layer are brazing filler metal layers,and the two outer sides of the brazing filler metal layers are brazing flux layers. The thickness of each brazing filler metal layer is consistent with that of the pure nickel layer, and the thicknessof each brazing flux layer is 1/3-1/2 of that of each brazing filler metal layer. Each brazing filler metal layer is prepared from the following raw materials in percentage by weight: 1.5-10% of Al and the balance of Zn. According to the laminated strip-shaped self-brazing filler metal, the pure nickel layer is arranged in the brazing filler metal and can play a role in shielding, hinder transition diffusion of copper and aluminum atoms and reduce generation of the brittle phases in a copper-aluminum joint. The brazing flux layers are arranged outside the brazing filler metal. After the brazing filler metal is heated, brazing flux on the outermost layers is melted firstly to play a role in pilot wetting and promote flowing joint filling of the brazing filler metal.

Description

Technical field[0001]The invention relates to the technical field of brazing materials, in particular to an aluminum-copper brazing laminated band-shaped self-brazing solder and a preparation method thereof.Background technique[0002]Copper and its alloys have excellent electrical conductivity, thermal conductivity, corrosion resistance and good processing and forming properties. Aluminum and its alloys also have low density, high specific strength, good low temperature performance, high thermal and electrical conductivity, and good processing performance. quality. At present, in the fields of automobiles, refrigeration, electric power, electronics, home appliances, etc., in order to take advantage of the respective performance advantages of copper and aluminum, while saving copper materials, reducing weight and costs, gratifying achievements have been made in replacing copper with aluminum. These achievements have been greatly achieved The extent depends on the development of copper...

AI Technical Summary

Problems solved by technology

However, there are some deficiencies in the existing zinc-aluminum flux-cored solder: the existing zinc-aluminum flux-cored solder has the problems of poor core filling coefficient stability, easy powder breakage, and hard powder core, especially hard powder core (seamless cored solder) Extrusion or seamed flux-core rolling and other processing processes), resulting in the outer layer of the brazing filler metal has been melted during the welding process, the core part of the brazing filler metal with a hard core fell off in pieces, difficult to heat and melt, out of sync with the brazing filler metal, very It is difficult to play a good role in film removal and flow aid, and the final welding performance becomes poor; when the existing zinc-aluminum flux-cored solder brazes copper-aluminum joints, the mutual diffusion between copper and aluminum atoms is relatively fast and deep, and it is easy to The formation of thick copper-aluminum brittle phases leads to problems such as poor toughness and low strength of copper-aluminum joints, which seriously limits the popularization and application of copper-aluminum joints

In order to solve this problem, the existing method is to plate nickel on copper or aluminum. Although nickel plating on copper or aluminum can reduce the generation of brittle phases to a certain extent, it depends on the thickness and bonding force of the coating to a large extent. , nickel plating on copper or aluminum adds a process when welding copper and aluminum, resulting in higher cost of copper and aluminum joints

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