HEAT EXCHANGER ASSEMBLY WITH MAGNESIUM BARRIER

摘要

PURPOSE: A more efficient magnesium barrier is provided within an improved heat exchanger assembly, and a stronger tubing or core material of a heat exchanger assembly is provided to lessen the weight thereof. CONSTITUTION: The improved heat exchanger assembly comprises at least one aluminum based tube(12) including magnesium adapted to be exposed to an ambient atmosphere and having an internal surface(14) and an external surface(16); an aluminum based cladding(18) disposed adjacent one of the internal and external surfaces(14,16); at least one aluminum based component(22) disposed adjacent the cladding; a brazing flux(13) applicable between the aluminum based cladding(18) and the aluminum based component(22) to facilitate brazing in the ambient atmosphere; and an aluminum based lithium enriched layer disposed between the one of the internal and external surfaces and the aluminum based cladding, wherein the aluminum based lithium enriched layer is adapted to scavenge sufficient oxygen from the ambient atmosphere during brazing to form a sufficient barrier against the diffusion of magnesium from the aluminum based tube that the formation of undesirable magnesium oxide is resisted.