Cadmium-free silver solder containing indium and silicon

Abstract

The invention relates to an indium and silicon-contained cadmium-free silver filler metal, which belongs to the field of medium-temperature brazing materials. The cadmium-free silver filler metal consists of chemical components accounting by weight percentage: 36 percent to 40 percent of copper, 25 percent to 35 percent of zinc, 0.5 percent to 4.5 percent of indium, 0.01 percent to 0.5 percent of silicon and 0.001 percent to 0.1 percent of microalloy elements and the allowance is silver; wherein, the microalloy elements are one or more of the alloying elements such as Ni, Mn, Sb, Zr, B, Ce, La, etc. The components are smelted and cast by adopting a conventional medium-frequency induction furnace, and then the required filler metal can be obtained by extruding, drawing, forming and washing the processed components. The temperature at which the indium and silicon-contained cadmium-free silver filler metal of the invention is melted ranges from 640 to 760 DEG C. By removing the hazardous element-cadmium, the alloy filler metal completely meets the requirement of the RoHS directive by European Union, removes the hazard caused to the health of the bodies of the operation employees and contaminations caused to the environment. By matching the FB102 flux and the silver filler metal of the invention for use, the invention can be applied to the brazing between the copper and workpieces such as copper alloy, hard alloy, stainless steel fitting, etc., and has the advantages of favorable wettability and fluidity, high mechanical strength of the brazed joint, good brazing process performance, etc. The mechanical property of the weld is equal to that of the silver filler metals such as BAg40CuZnCd, BAG45CuZnCd, BAG45CuZn, etc. The silver filler metal of the invention can be widely applied to the brazing in the industries such as refrigeration, machinery, electric machinery, electric apparatuses, instruments and meters, valves and pipe fittings, etc.

Description

Technical field: [0001] The invention relates to a cadmium-free silver solder containing indium and silicon, which is suitable for brazing workpieces such as copper and copper alloys, hard alloys, and stainless steel pipe fittings, and belongs to the field of medium-temperature brazing materials. Background technique: [0002] In response to the restrictions of the EU RoHS Directive, cadmium-containing silver solders such as BAg40CuZnCd, BAg45CuZnCd, and BAg50CuZnCd used for brazing in refrigeration, machinery, electromechanical, electrical appliances, instrumentation, valve fittings and other industries will gradually be banned or replaced. The harmful element cadmium (Cd) in these cadmium-containing silver solders endangers the health of operators and pollutes the environment. Simultaneously all contain higher noble metal silver in these brazing filler metals, because precious metal silver resources are limited, the price is more and more expensive. Therefore, research an...

AI Technical Summary

Problems solved by technology

The harmful element cadmium (Cd) in these cadmium-containing silver solders endangers the health of operators and pollutes the environment

At the same time, these brazing filler metals all contain high precious metal silver. Due to the limited resources of precious metal silver, the price is getting more and more expensive.