Research on corrosion of automobile condenser brazed with novel aluminium alloys

The corrosion behaviour of automobile condenser brazed with novel aluminium alloys have been studied in 0.1 mol/l NaCl(pH=6) and 0.6 mol/l NaCl(pH=3) solutions by microelectrochemical measurements and immersion test.The microstructure of the fin materials,tube alloys and brazing region and corrosion morphology have been investigated by SEM.The controlled atmosphere brazing(CAB) was used and Al-Si alloys was used for clad alloys for aluminium brazing sheet.The results indicate tube region shows less susceptibility to corrosion attack than the brazed region.The SEM results show that the tube region has no intergranular corrosion and the thickness of the brazed region is about 20-30 μm.The brazed region shows intergranular corrosion,but it is corrosion of the eutectic of Al-Si with α-aluminium is preferential dissolution and Si-rich intermetallic particles remains.