Strip-shaped brazing filler metal for lap joint brazing of copper plate and aluminum plate and preparation method thereof

Abstract

The invention belongs to the field of welding materials, and relates to strip-shaped brazing filler metal for lap joint brazing of a copper plate and an aluminum plate and a preparation method thereof. The strip-shaped brazing filler metal comprises a brazing filler metal body, a coating I and a coating II, the brazing filler metal body comprises the chemical components of 3.2%-4.5% of nano-zinc oxide, 6.8%-8.2% of selenium, 2.6%-4.2% of aluminum and the balance zinc, the coating I is composed of 90%-92% of surface modified nano-copper and the balance of polyvinyl alcohol, the coating II is composed of 90%-92% of surface modified nano-aluminum and the balance of polyvinyl alcohol, and the molecular weight of the polyvinyl alcohol is 8000 to 12000. According to the strip-shaped brazing filler metal for lap joint brazing of the copper plate and the aluminum plate and the preparation method thereof, the melting point of the brazing filler metal is 330 DEG C + / -10 DEG C, the wettability of the brazing filler metal is good, and due to the existence of the nano-zinc oxide, the nano-copper coating and the nano-aluminum coating, the shear strength of a copper plate and aluminum plate brazed joint is effectively improved and reaches 121 MPa or above. The preparation method is an innovation in the aspect of the strip-shaped brazing filler metal for lap joint brazing of the copper plate and the aluminum plate.

Description

technical field [0001] The invention belongs to the technical field of welding materials, and in particular relates to a strip-shaped brazing filler metal for overlapping brazing of a copper plate and an aluminum plate and a preparation method thereof. Background technique [0002] Copper is an excellent electrical and thermal conductive material with good calendering properties, and is widely used in power transmission, heat exchange, electronic products, refrigeration equipment and other fields. However, copper is a scarce metal and belongs to strategic resources. In recent years, the price of copper has remained high, which limits the application of copper. The shortage of copper resources and the resulting rise in copper prices have prompted scientific and technological workers to devote themselves to finding copper substitutes. Aluminum has excellent electrical and thermal conductivity, corrosion resistance and good processing performance, and is the best material to re...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent CN103317253B (application date is June 3, 2013) discloses a Zn-Al-Cu based solder for aluminum / copper brazing and its preparation method, which has high shear strength and good corrosion resistance , but using 5%-16% aluminum, the melting point of the solder obtained is 370°C-410°C, and the temperature is relatively high, which cannot fully meet the application of copper-aluminum brazing, and the excessive aluminum content and copper content cause brazing Cu 3 Al 2 and CuAl 2 The intermetallic compound weakens the shear strength of the brazed joint, and the summary of the invention and the examples do not give the experimental data of the shear strength

[0006] At present, the technical problems in this field are: the melting temperature of the solder is relatively high, resulting in poor wettability during brazing, and poor brazing processability; the shear strength of copper-aluminum joints is low

Images