Low-silver copper based high-performance brazing filler metal and preparation method thereof

Abstract

The invention discloses low-silver copper based high-performance brazing filler metal. The low-silver copper based high-performance brazing filler metal is prepared from the following raw materials inpercentage by mass: 1.5-2.5% of Ag, 6.5-7.5% of P, 0.5-1.5% of Sn, 0.01-2% of Ni, 0.001-0.1% of Si, 0.01-0.05% of Ce and the balance of copper and inevitable impurities, wherein purity of each raw material is 99.9% or higher. A preparation method for the low-silver copper based high-performance brazing filler metal comprises the following steps of: separately preparing Ni and Cu, P and Cu, Si andCu and Ce and Cu into intermediate alloys in specific proportions; then, sequentially adding metal Cu, Cu-P, Cu-Ni, Cu-Si and Cu-Ce to melt, and adding Sn and Ag after metal is completely molten; andimmediately adding borax after adding is completed, and performing post-treatment to obtain the low-silver copper based high-performance brazing filler metal. Production cost is greatly reduced, improved brazing filler metal is high in mechanical strength and is strong in production process, and a joint is attractive in appearance and is excellent in shearing strength; according to use feedback of a user, braze-welding process performances are excellent, the braze-welding joint is stable in quality, fatigue performance is good, the service life of the braze-welding joint can be effectively prolonged, and BCu80AgP braze-welding can be replaced.

Description

technical field [0001] The invention relates to the technical field of solder production, in particular to a low-silver copper-based high-performance solder and a preparation method thereof. Background technique [0002] According to the classification of melting temperature, solder can be divided into soft solder and hard solder. According to the type of substrate, hard solder can be divided into copper-based solder, silver-based solder, nickel-based solder, gold-based solder, and palladium-based solder. , Manganese-based brazing filler metals and other brazing filler metals. Copper-based solder, as a type of hard solder, has the following advantages when welding copper alloys and stainless steel: the price of copper-based solder is low; the conductivity of copper-based solder is relatively strong; the α-Cu structure in the weld structure It has strong shaping and strength; Cu atoms can diffuse beneficially with the base metal during the welding process to enhance the stre...

AI Technical Summary

Problems solved by technology

[0003] However, the traditional copper-based solder also has its disadvantages: Cu-Zn cadmium-free copper-based solder has a higher temperature and has a greater impact on the base metal after welding; the Cu-P phase has a strong brittleness and is harmful to the base metal. The α-Cu structure has a fatal impact on mechanical properties; although Cu atoms can be beneficially diffused, due to the short brazing time, the atomic migration energy of Cu atoms alone is not enough to achieve the desired effect

[0004] Now there is BCu88PAg brazing filler metal with better response in the market, but due to the addition of 5% silver element, its price is relatively high and the cost of use is greatly increased.

[0005] There are also some brazing filler metals with relatively good performances. For example, on December 29, 2016, the Chinese patent with the publication number CN106624448A discloses a new type of low-silver copper-phosphorus brazing filler metal. Although the mechanical strength of the brazing filler metal is It has been improved, but the impurity elements lead and bismuth are not protected during the brazing process, which affects the wettability of the solder

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