METALS AND THEIR TREATMENT 化学配方数据库

配方类型：	METALS AND THEIR TREATMENT
配方说明：	Blackening Copper
配方组成：	pH/5.6 to 5.8 With one solution containing about 16 oz/gal of proprietary salts, Formula No. Sodium or ammonium molybdate/0.2 oz/gal Treating time/3 to 5 min Nickel chloride (NiCl2.6H2O)/12 oz/gal Zinc chloride (ZnCl2)/5 oz/gal Ammonium chloride (NH4Cl)/5 oz/gal Sodium thiocyanate (NaSCN)/2.5 oz/gal pH/2.5 to 5.5 Anode current density/15 A/ft^2 Sodium hydroxide/24 oz/gal Nickel sulfate (NiSO4.6H2O)/23 oz/gal Ammonium molybdate [(NH4)2MoO4]/5 oz/gal Boric acid/3.5 oz/gal pH/4.3 to 4.7 Nickel sulfate (NiSO4.6H2O)/12 oz/gal Temperature/130 to 170'F Anodes/Graphite Nickel ammonium sulfate [NiSO4.(NH4)2SO4.6H2O]/7 oz/gal Sodium polysulfide/0.3 to 0.5 oz/gal Sodium or ammonium hydroxide/0.1 oz/gal Temperature/70 to 85'F Immersion time/0.5 to 2 min. Zinc sulfate (ZnSO4.6H2O)/6 oz/gal Temperature/180 to 200^2F Sodium thiocyanate (NaSCN)/2.5 oz/gal
配制方法：	After copper is cleaned and dipped in a dilute hydrochloric or sulfuric acid solution to remove oxide films, it is immersed in a sodium polysulfide bath agitated to displace the water film. Brass containing less than about 90 per cent Cu is sometimes activated in an acid solution that preferentially dissolves zinc. This darkens the film produced in polysulfide solutions. Films applied on conventionally cleaned alloys containing less than about 90 per cent Cu usually are a dark brown.