Copper-containing nickel-based brazing filler metal and preparation method thereof

The invention provides copper-containing nickel-based brazing filler metal and a preparation method thereof. The copper-containing nickel-based brazing filler metal comprises the following chemical components in percentage by mass: 5%-9% of Cr, 2%-4% of Fe, 3.5%-5.5% of Si, 2.5%-4% of B, 2.5%-10% of Cu and the balance of Ni. Cu-Ni and Fe-Cu are infinitely mutually soluble at a high temperature, so that the increase of a melting point caused by the reduction of the boron content can be made up to a certain extent by adding the copper element, the proportion of a solid solution is increased, and a brittle phase in the brazing filler metal is effectively reduced. The method has the advantages that (1) the prepared novel copper-containing nickel-based as-cast brazing filler metal is good in wettability, high in solid solution content and low in brittle phase proportion; (2) the new foil strip brazing filler metal has a good melting characteristic, uniform components, strong amorphous forming ability and good duct