A kind of low-silver and cadmium-free silver solder

Abstract

The invention discloses a low-silver cadmium-free silver solder. The low-silver cadmium-free silver solder comprises 11.0% to 13.0% of Ag, 36.0% to 43.0% of Zn, 0.01% to 0.05% of Ga, 0.01% to 0.05% ofNd, 0.01% to 0.05% of Zr, 0.01% to 0.05% of Sc, and the balance being Cu according to the mass percent. The solidus temperature of the low-silver cadmium-free silver solder is less than or equal to 765 DEG C; and the liquidus temperature of the low-silver cadmium-free silver solder is less than or equal to 795 DEG C. When the low-silver cadmium-free silver solder is used for soldering red copper-stainless steel, red copper-brass, and brass-stainless steel in cooperation with a commercially available FB102 soldering flux, the shear strength of a soldered joint is comparable to that of BAg45CuZn solder, and is superior to that of BAg12CuZn (Si) solder.

Description

technical field [0001] The invention belongs to the technical field of brazing materials of metal materials, and in particular relates to a low-silver and cadmium-free silver solder. Background technique [0002] The BAg45CuZn solder recommended in GB / T 10046-2018 "Silver Solder" has a melting temperature range of 665°C at the solidus line and 745°C at the liquidus line. It is a favorite solder material for solder users in the market. However, its Ag content of 45%±1% makes the material cost high for many highly competitive industries. Therefore, it is necessary to study how to reduce the content of Ag in silver solder. [0003] As a substitute for BAg45CuZn solder, BAg35CuZn, BAg34CuZnSn, BAg30CuZn, BAg25CuZn solder, except that the solidus and liquidus temperature of the solder is higher than that of the BAg45CuZn solder, most of the performance indicators can be close to the BAg45CuZn solder, but, Ag content is still high. In recent years, solders with lower silver con...

AI Technical Summary

Problems solved by technology

The price of Sn element is not high and the reserves are abundant, however, it is easy to form hard and brittle intermetallic compound Cu 6 sn 5 , making it difficult to process silver solder. Except that the addition of Sn in BAg60CuSn solder can reach 9.5% to 10.5%, the general addition in Ag-Cu-Zn-Sn series solder is 1.5% to 2.5%. For example, the addition of Sn in BAg56CuZnSn is 4.5% to 5.5% (see Table 1 on page 4 of GB / T 10046-2018 "Silver Solder" (continued))

[0005] However, in the silver solder whose main components are Ag, Cu, and Zn elements (excluding phosphorus elements), the content of Ag is less than 20%, and the content of trace elements such as In and Sn is less than 0.15%. There are no cadmium-free silver solders, and there are no reports of low-silver solders with properties such as wetting and spreading properties and mechanical properties of the solder joint that can approach BAg45CuZn solders and liquidus temperatures below 800 °C.

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