| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the utilization factor and the long-term reliability of a positive-electrode active material and reduce its cost, by using two nickel plating layers different in sulfur contents formed on a surface of unsintered substrate of iron powder having three-dimensionally continuous spaces to be filled with active-material powder. SOLUTION: A first nickel plating layer on a surface of low-cost, unsintered substrate of iron powder includes sulfur of 0.001 to 0.005 wt.% of the amount of plating, a second nickel plating layer thereon includes sulfur of 0.01 to 0.5 wt.% of the amount of plating, and the total thickness of the two layers is preferably 1 to 30μm. When a storage battery is made up, an iron base portion not plated with nickel forms a local battery together with the nickel plating via an alkaline electrolyte, and is covered with nickel eluted from the first plating layer, and the second plating layer makes up for the nickel. Accordingly, the substrate is completely protected and iron is not eluted therefrom. Preferably, the second nickel plating layer is further plated with chromium of 1 to 3μm, and corrosion resistance of the substrate is thereby improved.</p> |
