Ag-based composite brazing foil and preparing method thereof

Abstract

The invention discloses Ag-based composite brazing foil and a preparing method thereof, which is used for brazing electric vacuum components. The thickness of the Ag-based composite brazing foil is 0.05-1mm, the Sn content is 19-21%, the Cu content is 21-23%, and the rest is Ag. The preparing method of the Ag-based composite brazing foil comprises the following steps: orderly stacking Ag layers, Cu layers and Sn layers which are the same in size and 0.05-0.5mm in thickness according to the structure mode of Ag/Sn/Cu/Sn/Ag/.../Ag/Sn/Cu/Sn/Ag; making an Ag-Cu-Sn multi-layer composite blank of which the total layer number is 5-30 through pre-compression; then carrying out rolling to make Ag-Cu-Sn foil of which the thickness is 0.05-1mm; and after the following heat treatment, obtaining the Ag-based composite brazing foil. The prepared foil product has great tenacity and ductility, can be made into various sizes of premolding soldering lugs through cold blanking, and has great wetting property and welding property on base materials, such as copper, nickel, high-temperature alloy and kovar alloy.

Description

technical field [0001] The invention relates to a solder, in particular to a silver-based composite solder foil and a preparation method thereof. Background technique [0002] Brazing is one of the important methods for connecting metal materials and is a key connection technology in many fields. Brazing filler metal is a filler added to the gap between brazing joints to achieve the combination of two materials. It can be divided into hard solder and soft solder according to its melting temperature range. Precious metal brazing filler metal is an important class of non-ferrous metal brazing filler metal. It has moderate melting temperature, wide range of wettable substrates, and excellent mechanical properties of brazed joints. Its research and development and application have been widely concerned. [0003] Precious metal brazing filler metals refer to alloy brazing filler metals made of gold, silver, palladium, platinum and other precious metals and their alloys. Gold-bas...

AI Technical Summary

Problems solved by technology

The melting point of Sn is only 231.89°C. Adding 12-20wt.% Sn to the Ag-Cu alloy can make the melting temperature of the alloy at 400-600°C. The microstructure of the alloy is mainly composed of Ag-rich α phase and Cu-rich phase. , Sn β phase composition, with the increase of Sn content, various electronic compounds such as β', γ', ε1, ε', δ, etc. will appear in the alloy. The existence of these electronic compounds will reduce the plasticity of the alloy and increase the brittleness. , it is difficult to use traditional rolling, drawing and other processes to process into welding sheet or welding wire

Existing studies have shown that only when the Sn content in the solder is ≤12wt.%, the Ag-Cu-Sn alloy has good processability, and when the Sn content is ≥15wt.%, the alloy basically has no processability

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