Using Sulfamate Nickel Strike for Preplating Nickel and Other
Metals
A sulfamate nickel strike is used to deposit an active coating
of nickel on metal substrates to assure positive adhesion of subsequent
coatings. The nickel coating is relatively pure and without organic
components, so that it remains active for long periods of time.
Sulfamate strikes may be used to plate over stainless steel, nickel
and other steel alloys and potentially passive deposits.
Sulfamate strikes operate over hard-to-plate surfaces, and demonstrate
some advantages over Woods nickel formulations because of some
of the properties of the solutions formulation and deposit characteristics.
Both Woods nickel and sulfamate strikes operate at low pH and
both have a component of chloride in their solutions. The corrosiveness
and propensity for contamination are significantly lower in sulfamate
nickel strikes. These may operate at a more-steady state than
a Woods system. Sulfamate strikes also are easier to purify than
Woods formulations and operate at a much higher efficiency. Efficiencies
of 50-60 percent can be attained, as opposed to the 7-9 percent
demonstrated by a Woods formulation.
A disadvantage of the sulfamate system is that it is more expensive
to makeup and maintain, because of the higher cost of the basic
materials. But, because of the manageability of the process, it
may, indeed, be more cost effective than the Woods systems. I
have found that sulfamate systems are, in general, poorly understood
and under-used. There are some benefits because of the extreme
solubility of sulfamate salts that can make a real difference
in many operations. When using sulfamic bases, pickling, plating
solutions and different operations may demonstrate some positive
results.
Make-up of a sulfamate strike:
Anodes should be S-Nickel in titanium baskets.