A METHOD FOR THE FLUXLESS BRAZING OR WELDING OF ALUMINIUM

摘要

A method of fluxless brazing of aluminum parts is disclosed. Gaseous species, such as O2 and H2O, which inhibit wetting are controlled by rapid heating (at least 100 DEG C./min) through a critical temperature range (such as 400 DEG -590 DEG C.) during heat-up to brazing temperatures. The formation of porosity through the oxide film and the collection of a promoter and wetting agent at the interface with the oxide film will thus occur simultaneously precluding disruption of wetting action by gaseous O2 or H2O. Wicking of the wetting agent through the film porosity in the critical temperature range will then take place because of the limited time available for the reaction of gaseous O2 and H2O with the film to form a duplex oxide. Heating may be carried out in a vacuum of 10-3 Torr or less or in an inert atmosphere with pulsed heating, provided the critical heating rate is observed in said critical temperature range.