Vacuum brazing of common metals

    The brazing of oxygen-free copper and its alloys can be carried out in a hydrogen furnace or a vacuum furnace. Commonly used solders are Ag100, Ag90Cu10, Ag72Cu28. However, gold copper, gold nickel, germanium nickel, silver copper palladium, etc. can also be used. Copper and copper alloys are plated with silver or gold before brazing, and the brazing performance is better. For copper alloys containing easily oxidized chromium, aluminum, beryllium, titanium, and zirconium, electroplating must be carried out before welding and brazing in a vacuum furnace.

    Kovar alloy is easy to braze. The commonly used solders are silver copper, gold nickel, silver copper palladium, gold copper, germanium copper and so on. When brazing with silver-based solder, pre-welding annealing is required to eliminate the stress caused by mechanical processing. Kovar surface should be plated with copper or nickel to prevent cracking caused by solder penetration. The brazing can be carried out in a hydrogen furnace or a vacuum furnace.

    1Cr18Ni9Ti stainless steel can be brazed with silver-based, copper-based, and gold-based solders, but the surface of the substrate must be plated with copper or nickel before brazing to prevent the formation of stable oxides on the surface of the stainless steel and increase the wettability of the solder. Silver-copper-palladium alloy solder is used, and the stainless steel surface can be electroplated. The brazing of stainless steel can be carried out in a hydrogen furnace or a vacuum furnace.

    Commonly used solders for brazing of titanium are nickel, copper, titanium and so on. Welding must be carried out in a vacuum furnace with a pressure lower than 10^-3Pa. Because titanium and hydrogen can generate titanium hydride at high temperatures, brazing cannot be performed in a hydrogen furnace.

(Huiputech)