In order to obtain high strength aluminum butt-joints with high corrosion resistance, ultrasonic soldering of 1070 and 5056 rods was conducted using quasi-melting Zn-18Sn(mass%) alloy and Zn-38Al alloy. Ultrasonic vibrations were applied at soldering temperature ranging 533-723 K through aluminum rods without using of a solder bath. To evaluate the corrosion resistance of solder joints, tensile tests were conducted after immersion in 5% NaCl aqueous solution.Though joint strength decreased with increase of immersion time NaCl aqueous solution because of corrosion in the joints, corrosion resistance of 5056 joints with Zn-38Al alloy was higher than that of joints with Zn-18Sn alloy irrespective of aluminum base material. The strength of joints with Zn-18Sn alloy rapidly decreased by immersion in NaCl aqueous solution. In these joints, corrosion occurred locally in the soldered interface. Corrosion potential of these joints was unusually lower than that of the solder alloy. In contact, corrosion occurred slowly in the solder layer in 5056 joints with Zn-38Al alloy. Corrosion potential of the joints was equvalent to that of the solder alloy.

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