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.