Thin film brazing of aluminum shapes

摘要

An improved method of brazing of two unclad aluminum shapes, particularly for automotive heat exchangers, which brazing joint does not leave a physically apparent layer of brazing material and which effects a stronger, sounder autogenous joint. A thin film of aluminum eutectic forming material (Si, Al-Si or Al-Zn) is deposited onto a zone of at least one of the shapes to be brazed or joined. The shapes are placed in joining relationship to form an assembly with a joint at the zone. The assembly is heated to a temperature to diffuse the eutectic forming material into the aluminum members to form a sacrificial bond between the shapes at the joining zone. It is desirable that at least one of the unclad aluminum shapes to be joined is extruded tubing having a precise diametrical configuration and said film is deposited as a physically vapor deposited layer in a thickness range of 1-50 microns.