Al-0.1 mass%Sn合金の電気化学的性質に及ぼす各種添加元素の影響

Abstract

Effects of addition of a small amount of Fe, Si, Cu, Mn or Mg on the electrochemical property and the corrosion resistance of an Al-0.1 mass%Sn alloy were examined. The corrosion potential of the alloy was remarkably less noble, when it was water-quenched after the solution treatment, while it became noble when furnace-cooled, because of the precipitation of Sn. The addition of Cu, Si or Mn made the corrosion potential of quenched alloy noble, while that of Mg or Fe gave little effect. The additional elements had essentially no effect on the precipitation of Sn of the alloy. These suggest the effect of Cu, Si or Mn in the solid solution is greater than that of Sn on the electrochemical property of aluminum.Corrosion rates of less noble alloys in an acidified chloride solution which simulated the solution of anodic area were unusually high, but those of noble ones were sufficiently low. The anodic efficiency in galvanostatic dissolution was lower in the less noble ones, but much higher in the noble ones. These results show that the anodic efficiency is controlled by the corrosion rate of anodic area which is closely related with the electrochemical property of the alloys and that an alloy with both a higher efficiency and an excellent sacrificial anode effect can be hardly obtained in these ternary alloys examined.