| 摘要 |
PURPOSE:To obtain a selective absorption film having a selective absorptivity as excellent as the conventional black chromium film, which permits plating operation under a low current density, by forming a black film consisting of a metal and nickel over the surface of a metal member by way of plating. CONSTITUTION:A plating bath of this invention is obtained by adding either of sodium arsenite, cupric chloride, or sodium arsenite plus cobalt sulfate to nickel sulfanilate. Here, it is preferable to select the amount of the above substances to be added at about 1-3g/l for sodium arsenite, about 0.5-3g/l for cupric chloride, about 2g/l for cobalt sulfate, and about 30-70g/l for nickel sulfanilate, respectively. By performing plating operation under the conditions of a current density of about 0.2-2A/dm<2>, pH of the plating bath of about 3.6-6.5, bath temperature of 50-55 deg.C, it is enabled to obtain a selective absorption film superior in its selective absorptivity, weather-resisting performance and heat-resisting performance. |
