A kind of low-silver copper-based solder and preparation method thereof

Abstract

The invention relates to a low-silver-copper-based brazing filler metal and a preparation method thereof. The low-silver-copper-based brazing filler metal comprises Ag, Cu and P, wherein Sn, Ni and rare earth are further added, the weight percentages of the components are as follows: 1.5%-2.5% of Ag, 5.5%-6.6% of P, 5%-7% of Sn, 1.0-2.5% of Ni, not more than 0.05% of rare earth and the balance of Cu; the preparation method of the low-silver-copper-based brazing filler metal comprises the following steps of preparing Sn to filament Sn, smelting, continuously casting, continuously extruding, forming and cleaning to obtain the brazing filler metal. The brazing filler metal has the advantages of reasonable formulation design, lower brazing filler metal melting temperature, good wettability and mobility, stable quality of a soldered joint and long service life; a BCu80AgP copper-phosphorus brazing filler metal can be replaced, and the production cost of motor brazing is greatly reduced. The preparation method of the brazing filler metal can effectively solve a segregation problem of Sn, a preparation process is optimized, and the quality of the prepared brazing filler metal is remarkably improved.

Description

technical field [0001] The invention relates to a low-silver copper-based solder and a preparation method thereof, which is suitable for brazing in industries such as motors and machinery, and belongs to the field of brazing materials. Background technique [0002] In recent years, due to the increasingly fierce market competition and limited precious metal resources, the requirements of "reducing costs and reducing the amount of precious metal silver" have been put forward for brazing materials commonly used in machinery, motors and other industries. 15% BCu80AgP requires brazing material manufacturers to develop new brazing materials with lower silver content. [0003] Copper-phosphorus solders with less silver content are common on the market at present, such as BCu89PAg copper-phosphorus solder containing 5% silver, BCu91PAg copper-phosphorus solder containing 2% silver, etc. Although these copper-phosphorus solders are relatively low in price, they are The corrosion re...

AI Technical Summary

Problems solved by technology

The temperature range between the solidus line and the liquidus line of the existing low-silver copper-phosphorus solder is too large, while the high-silver copper-phosphorus solder has a relatively high silver content and high production and use costs, which will gradually fail to meet the needs of brazing on motors , thus hindering the development of solder in the motor industry

[0006] On the other hand, the smelting of Sn-containing copper-based solder in the industry is prone to Sn segregation, resulting in poor control of the composition of the Sn-containing copper-based solder, resulting in insufficient solder performance. It is urgent to develop a method that can avoid Sn segregation. smelting preparation process

[0007] Chinese Patent No. 200510023129.5 discloses a patent titled "a copper-based brazing alloy", which selectively adds manganese, zinc, silver, nickel, silicon, Tin, aluminum, lithium, rare earth, the welding process performance is similar to that of silver solder, and the cost is more than 1 times lower than that of general silver solder; but this brazing alloy cannot replace BCu80AgP with 15% silver in the motor industry, patented There is no mention of the solution to the Sn segregation problem, and the above-mentioned defects in the prior art are not overcome.

[0008] Chinese Patent No. 200710102635.2 discloses a patent named "Copper-Phosphorus Brazing Alloy Containing Tin and Nickel", which contains tin (Sn) and nickel (Ni) in addition to the traditional copper-phosphorus brazing alloy constituent elements, The tensile strength is better, and it does not contain silver elements, the working temperature is lowered, brazing can be operated at low temperature, the oxidation and deformation of the base material are reduced, and the cost is reduced; Silver 15% BCu80AgP, the patent does not mention the solution to the Sn segregation problem, and does not overcome the above-mentioned defects in the prior art

[0009] Chinese Patent No. 200910097437.0 discloses a patent titled "a low-silver copper-based medium-temperature solder", which adds P, In, Ni, and Ga to the copper-based solder, and the Ag content is only 1.8%-5%. It can completely replace BAg25CuZnSn silver solder for brazing in refrigeration, machinery, electromechanical, electrical appliances, instrumentation, valve fittings and other industries; Contains Sn, does not overcome the above-mentioned defects in the prior art