配方类型：	METALS AND THEIR TREATMENT
配方说明：	Plating On Magnesium
配方组成：	Tetrasodium Pyrophosphate/16.00 oz. per gal. Zinc Sulfate Monohydrate/4.00 oz. per gal. Potassium Fluoride/0.94 oz. pr gal. Potassium Carbonate/0.67 oz. per gal. After application of the zinc immersion coating, the parts are coated with a thin copper deposit in a Rochelle salt copper strike of the following composition 60% Hydrofluoric Acid/1 fl. oz. per gal. Temperature/75-180F. Mild agitation pH/10.0-10.6 Chromic Acid/37.5 oz. per gal. Copper Cyanide/
配制方法：	Electrical contact is made as quickly as possible at a high current density of 30 amp. per sq. ft. for the first 30 seconds. The current density is then decreased to 20 amp. per sq. ft. for 5.5 minutes. This is necessary to cover the zinc immersion coating as quickly as possible to prevent its destruction by the copper cyanide solution. A pyrophosphate-type copper solution is used for copper plating. The pyrophosphate bath is modified by the addition of 30 to 60 g. per liter of potassium fluoride, to minimize attack in the event of porosity in the strike or failure to cover. A minimum of 0.0008 inn. of copper is deposited in this solution operated at 130F. for approximately 35 minutes at 25 amp. per sq. ft. A Watts-type bright nickel solution, operating at a pH of 4.5, is used for nickel plating. The parts are plated with a minimum of 0.0002 in. nickel, or for approximately 15 minutes at 25 amp. per sq. ft. The operating temperature is 130F. For chromium plating, a standard chromic acid

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