Metallic Coatings for Brazing Aluminum Alloys

Abstract

Because of their high specific strength and satisfactory corrosion resistance, aluminum alloys belong to the group of fundamental structural materials in modern engineering. Their wide use has been made possible as a result of developing advanced methods of processing and producing permanent joints by welding or brazing. However, the application of brazing aluminum alloys is limited because of the problems in removing the strong and chemically resistant oxide film. These problems can be overcome by using metallic coatings which themselves do not oxidize during heating in vacuum and, when deposited, the oxide film is broken up and can be removed from the surface of the parent material. The most promising method is to use metallic coatings in the form of individual components of the brazing alloy which forms in contact melting of the deposited coatings with aluminum in heating for brazing. This brazing method is referred to as contact-reactive brazing and is used widely for brazing aluminum alloys. This article provides an overview of the contact-reactive brazing process.