| 配制方法： |
The method for producing a black anodic oxide coating on an alloy consisting by weight essentially of from 0.2 to 0.6% silicon, up to 0.35% iron, up to 0.10% copper, up to 0.10% manganese, from about 0.45 to about 0.9% magnesium, up to about 0.10% chromium, up to about 0.10% zinc, up to about 0.10% titanium and up to 0.15% others, and the balance aluminum which comprises immersing said alloy in an aqueous electrolyte maintained at a temperature of from about 45F to about 85F and consisting essentially of from about 25 g/l to about 150 g/l of sulfophthalic acid and from about 0.1 g/l to about 15 g/l of sulfuric acid, as the anode in a direct current electrical circuit which includes said electrolyte, anodizing said alloy at approximately constant current density of from about 25 amp per square foot to about 40 amp per square foot until a preselected voltage of from about 55 to about 75 volts is reached, and subsequently anodizing said alloy while maintaining said preselected voltage approximately constant un |