| 摘要 |
PURPOSE:To form a plating layer composed of Pt and Ir having low oxygen overvoltage at a low cost, by holding an weakly acid plating liquid containing a Pt compound, an Ir compound and NH2NH2 at one surface of an ion-exchange membrane, and letting an alkali solution penetrate into said membrane from the other surface to perform reducing reaction. CONSTITUTION:A plating liquid containing a platinum compound (e.g. chloroplatinic acid), an Ir compound (e.g. IrCl4) and NH2NH2, and being adjusted to a pH of 5-6 is held at one surface of an ion-exchange membrane. The pH of the plating solution is adjusted by an aqueous alkali solution and maintained in said pH range by a buffer such as citric acid or sodium citrate. Under this condition, an alkali solution such as NaOH is let penetrate into the ion-exchange membrane from the other surface, so that the reducing reaction with NH2NH2 in the presence of the penetrating alkali is brought out on the former surface of said membrane. Thus, an electrode, esp. an anode, composed of Pt and Ir is formed on said membrane. |
