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This versatile zinc-nickel coating provides a range of durable finishes
By Thom Loree
Nickel Magazine, December 2007 -- A new decorative black nickel plating
technology is quickly finding favour in the auto industry and elsewhere.
The process, known as Nickstar, deposits a thin and highly uniform over-coat of black zinc-nickel alloy,
preserving the substrate’s brightness while producing a rich, totally black nickel finish. That makes it
ideal for the decorative trim of car interiors, in particular molding and handles, that require
non-reflective properties.
In addition to diminishing glare, Nickstar improves durability. For both these reasons, it’s also used in
the manufacture of certain upscale sporting goods such as golf clubs and goalie masks for hockey.
“There’s a growing demand for black nickel finish,” says Don Walsh, director of operations for the company
which developed the technology, Uyemura U.S.A., which is based in Ontario, California. “For many years, the
tradition was bright nickel; in the past 10 years, the trend has been for different blends and shades of
satin nickel; and now, black finish is the way to go.”
The lustrous, highly versatile Nickstar alloy contains 50-60% zinc and 40-50% nickel within the deposit.
The coating is applied by electrolytic plating onto bright nickel, brass or copper surfaces.
“The nickel is a key component of the deposit’s black appearance and provides hardness, adhesion and
corrosion resistance,” says Walsh.
A deposit thickness of up to 2 microns can be applied in rack or barrel plating equipment. If a thicker
deposit, or a high corrosion performance, is required, a heavier nickel undercoat can be used.
Greater hardness can be achieved with an optional salt additive. As well, colour density can be modified
from darkest black to softer hues.
Nickstar can be operated at higher current density to speed the plating process --specifically 5-8 amps
per square foot versus 1-3 for conventional black nickel. Moreover, it achieves a deep black deposit in 5-10
minutes, compared with the 15-20 minutes required for traditional black nickel processes.
“In a nutshell, you can put it on faster and smoother,” says Walsh.
Nickstar produces a uniform black deposit by means of “easy-to-run chemistry that nonetheless ensures
durability,” says Mario Orduz, National Product Manager for Uyemura U.S.A. He adds: “It’s the black finish –
brilliant yet non-reflective – that’s so desirable.”
The process utilizes both the nickel and the zinc in combination to provide a high degree of corrosion
resistance. In industry standard tests, the corrosion resistance of black nickel coating easily outperforms
that of conventional coatings.
Uyemura also offers an option to Nickstar, known as Nicostar, which is even more resistant to corrosion,
thanks to a co-deposit of cobalt.
“Nicostar is a little harder and therefore more resistant to wear” says Orduz. “But it’s slightly lighter
in colour than Nickstar. So some customers prefer one, some the other.”
Besides decorative trim for the inside of cars, Nickstar is used in the military, where corrosion
resistance and non-reflective requirements are essential. Other applications include architecture and
construction (for example, door and cabinet handles, locks, and assorted other fixtures) and police and
security badges.
The Nickstar chemistry contains no lead or cadmium and meets all requirements of the RoHS Directive, which
restricts the use of certain hazardous substances in electrical and electronic equipment in the EU
market.
Uyemura U.S.A. serves the printed circuit industry and specializes in surface finishing technology. It is
a subsidiary of Uyemura International Corporation, a publicly traded R&D company based in Osaka,
Japan.
Thom Loree is a Toronto-based freelance writer.
Photos: Uyemura U.S.A. and iStock
Don Walsh
Director of Operations
Mario Orduz
National Product Manager
Uyemura U.S.A.
Uyemura U.S.A. Technical Center
240 Town Line Rd.
Southington, CT. 06489
U.S.A.
Tel: +1-860-793-4011 or +1-860-793-4020
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