| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of the making of the anode potential into the noble one, the reduction of effective electric quantity, the local pitting dissolution or the like and to obtain stable sacrificial performance by allowing the anode to have a compsn. contg. specified ratios of Zn, Mg, In, Si, B, Ga, and the balance Al with inevitable impurities. SOLUTION: This anode is composed of an aluminum alloy having a compsn. contg., by weight, 2.0 to 6.0% Zn, 1.0 to 5.0% Mg, 0.022 to 0.060% In, 0.05 to 0.30% Si, 0.001 to 0.500% B, 0.010 to 0.050% Ga, and the balance Al with inevitable impurities. More preferably, the contents of B and Ga are respectively limited to 0.022 to 0.200% B and 0.015 to 0.030% Ga. The sacrificial anode using this aluminum material has high effective electric quantity while a base anode potential is retained, exhibits general solubility and is not passivated in an environment in which the temp. of seawater drops near to 0 deg.C. |
