Nickel baths mainly bath soluble organic compounds, are added, mostly of the Watts type with widely varying proportions of chloride and sulfate. Boric acid is always present, usually not less than 35 g/l. Condition of cathode film must be favorable not only for the deposition of nicker but also for the functioning of the brighterers function, the best condition are at pH about 3 to 5 and bath temperature at about 50 to 65 oC.
The nickel brighteners fall into two distinct classes. Aromatic sulfonic acids, sulfonamides have been designed class I nickel brighteners. The aromatic rings to which the sulfon group is attached are generally benzene and naphthalene rings. These brighteners produce almost bright or cloudy bright plate on buffed surfaces but are unable to build higher luster with continued plating. Class I aromatic sulfon brighteners have no critical upper concentration and are used in relatively high concentration and are used in relatively high concentration (1-10 g/l) without significantly affecting the adhesion and the limiting current density. The decrease the tensile stress of the deposit and can with increasing concentration endow the plate with compress stress. Sulfur is introduced into the plate, about 0.03% at pH value 3 to 5 when the class I compounds are used in warm baths without class II brighteners. The sulfur is present as sulfide, and the plate is harder and of brighter tensile strength, but less ductile than the normal dull Watts nickel plate.
The nickel brighteners fall into two distinct classes. Aromatic sulfonic acids, sulfonamides have been designed class I nickel brighteners. The aromatic rings to which the sulfon group is attached are generally benzene and naphthalene rings. These brighteners produce almost bright or cloudy bright plate on buffed surfaces but are unable to build higher luster with continued plating. Class I aromatic sulfon brighteners have no critical upper concentration and are used in relatively high concentration and are used in relatively high concentration (1-10 g/l) without significantly affecting the adhesion and the limiting current density. The decrease the tensile stress of the deposit and can with increasing concentration endow the plate with compress stress. Sulfur is introduced into the plate, about 0.03% at pH value 3 to 5 when the class I compounds are used in warm baths without class II brighteners. The sulfur is present as sulfide, and the plate is harder and of brighter tensile strength, but less ductile than the normal dull Watts nickel plate.