| 配方類型： |
METALS AND THEIR TREATMENT |
| 配方說明： |
Blackening Copper |
| 配方組成： |
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 o |
| 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. |
