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Electroless Nickel an autocatylitic process which deposits a uniform coating of phosphorous
nickel on a variety of substrates. The coating, as plated, has a hardness of
RC 48-52. The coating can be heat treated to achieve a hardness of RC 70. The
deposit may have a low, mid or high phosphorous content depending on the
application. Thickness of the deposit is typically .003 in or less.
Electroless nickel also serves as an alternative to a electrolytic process
and, in most cases, will plate internal or hard to reach areas without the
aid of expensive tooling.
Cadmium is a soft metal that can be
electrodeposited on ferrous substrates primarily for corrosion resistance. It
is frequently chromated and used as a base for paint to give maximum
protection to aircraft and ordinance parts. Deposits are generally less than
.001 inch thick, but will vary with each application.
Low
Hydrogen Embrittlement Cadmium (LHE) is deposited from an unbrightened cadmium bath
which will allow hydrogen to escape from parts during the hydrogen
embrittlement relief bake. This coating is specified by McDonnell Douglas.
Deposits are generally less than .001 inch thick, but will vary with each
application.
Titanium-Cadmium
(Ti-Cad) is
deposited from a special bath developed by Boeing. It has excellent corrosion
resistance and improved characteristics to allow removal of hydrogen from
parts during the hydrogen embrittlement bake. Deposits are generally less
than .001 inch thick, but will vary with each application.
Vacuum-Cadmium
(Vac-Cad) is
a coating applied to parts by vaporization of cadmium pellets in a vacuum chamber.
It is soft and has excellent corrosion resistance. When chromated it is an
excellent base for paint. Deposit thickness is from .0001 in. to .0005 in.
depending on application. Vac-Cad is generally used for critical aircraft,
missile or ordinance hardware that are designed to operate very near their
ultimate strength limits. Vac-Cad is ideal for these types of parts because
hydrogen is not induced into the metal meaning hydrogen embrittlement cannot
occur. The result is no reduced tensile strength. Typical applications
include landing gear components, pins, yokes, hooks, springs, fragile
components in ordinance and fuel systems.
Zinc-Nickel is an alloy applied with a Boeing
patented process that provides the corrosion protection of cadmium with the ability
to operate at high temperatures. In some cases it can replace diffused
nickel-cadmium. The deposit contains 11% nickel with the balance being zinc.
The process produces a patented structure which facilitates migration of
elemental hydrogen normally resulting from electrolytic plating and is
removed by baking. The application process normally includes a chromate
conversion coating.
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