表面処理による銅端子とアルミ電線の間に生じるガルバニック腐食の防止

抄録

Research was conducted to prevent galvanic corrosion, which occurs between the Al wires and Cu terminals of the aluminum wire harness, by surface treatment. When zinc is added by 2 wt% or more to the tin electrodeposit, the corrosion potential becomes lower than the pitting potential of aluminum, and the aluminum wires can be protected. As a method for alloying Sn and Zn, the method of electrodeposition, the method of supplying Zn from the Zn underplate to the Sn surface, and the method of reflowing Sn and Zn were compared. As a result, in the method by electrodeposition, Zn was deposited as a concentrated phase in Sn layer. That concentrated phase of Zn was dissolved early, and the effect of keeping the low potential was not maintained for a long time. The method of reflowing Sn and Zn was inferior to the other methods in the anticorrosive effect. The method of supplying Zn from the Zn underplate to the Sn surface showed an excellent anticorrosive effect over a long period of time as compared with the electrodeposited Sn–Zn alloy in which the Sn phase and the Zn phase are separated. The surface treatment found in this study eliminates the need for anticorrosion treatment such as resin molding, which is conventionally used for aluminum wire harnesses, and is expected to contribute to the miniaturization and cost reduction of aluminum wire harnesses.