Low-silver brazing material for dissimilar metal connecting

Abstract

The invention relates to a low-silver brazing material for dissimilar metal connecting. The low-silver brazing material for dissimilar metal connecting is characterized by comprising, by weight, 13.0-18.0% of silver, 42.0-48.0% of copper, 1.0-4.0% of tin, 0.1-3.0% of indium, 0.001-0.05% of trace mixed metal, and the balance zinc; the trace mixed metal is composed of two or more of lanthanum, cerium, gallium and silicon. According to the low-silver brazing material for dissimilar metal connecting, the silver content is low, no cadmium exists, the cost performance is high, superior mechanical performance is achieved when copper and iron are brazed, quality is stable, the machining plasticity is good, and the specific resistance is small.

Description

technical field [0001] The invention relates to a novel multi-component low-silver solder containing elements such as indium and tin, which is especially suitable for brazing of dissimilar metal materials such as copper and iron, and belongs to a medium-temperature brazing material. Background technique [0002] According to the domestic and foreign development status and market analysis, in order to cope with the rising trend of silver prices in the raw material market and effectively reduce the production cost of products, there are many complete machine products involving copper and iron connection in the current market, and the application fields are wide, such as in The copper and iron pipe fittings inside various air-conditioning and freezer compressors are connected, but high-silver solder with a silver content of more than 20% is often used for brazing connection, which increases the production cost of customers. [0003] When brazing ferrous metals such as copper an...

AI Technical Summary

Problems solved by technology

However, as the price of precious metal raw materials continues to rise, manufacturers using high-silver solder for brazing are facing huge cost pressures. Under fierce market competition, the competition of companies using silver solder with a silver content greater than 20% has been greatly weakened. force

[0004] Some companies reduce the silver content by increasing the content of Cd. The addition of Cd greatly reduces the melting temperature of the solder, improves the brazing performance, and reduces the silver content. It was once widely tested, but Cd itself is Toxic elements are not conducive to the health of operators and pollute the environment. They do not comply with the EU RoHS directive. As people pay more and more attention to environmental protection, they are gradually replaced by other harmless elements.

[0005] However, according to the existing research results, the addition of a single element is not enough to compare with cadmium-containing silver solder. For example, the addition of Sn in Ag-Cu-Zn-Sn solder can effectively improve fluidity and wettability. Lower the solidus and liquidus temperature and reduce the melting range, but its machinability is often poor; the addition of In in the Ag-Cu-Zn-In solder can reduce the solid and liquidus temperature, reduce the melting range, and improve Fluidity, but its solid solubility in silver and copper is small and the price is high; people began to focus on the development of silver solders with multi-alloy systems to replace the use of cadmium-containing silver solders

[0006] However, when multiple elements are added, due to the interaction of elements and the influence of the addition amount, the brittle phase inside the alloy material will be precipitated, and the mechanical properties of the solder itself will be deteriorated. It is prone to fracture and stop when used in automated production, which affects mass production. application

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