Zinc Brazing of Automotive Aluminum Heat Exchangers

Provision of a layer of zinc on aluminium to provide the fillets for soldering is well established but this usually necessitates a thick layer of zinc (>30μm) and soldering at temperatures below 450°C.

New technology has been developed to enable sound joints to be made on aluminium heat exchangers using a much thinner layer of zinc (4 to 8 μm typically) on the aluminium component to provide the joint. By the correct combination of flux and zinc coating thickness, joints have been obtained over a wide range of heating conditions.

Preferred temperature cycles are similar to those used by the industry today for brazing of Aluminium:Silicon braze-clad aluminium components which should facilitate tranfer by industry to the new technology.