Finishing - September-October 2021

34 ELECTROPLATING
definitely ‘selective’. Nickel plating that mirrors
the performance characteristics of ENP can be
applied accurately to small and clearly defined
areas without the need to immerse the part in
a plating bath. This does away with the need
to replate the whole part, and in many cases,
the need to disassemble components too.
More importantly perhaps, the plating
equipment can be taken to the part and
applied in situ, eliminating the need to remove
it and all the associated costs of downtime and
delays.
So how does it work, and how
effective is it?
Selective electroplating is actually a longestablished
technology, originally developed in
1938. Today, the SIFCO Process® of selective
plating has approvals across multiple
industries, including military, aerospace, and
energy, and comes with powerful
recommendations.
In selective (or brush) plating, an electric
current is run through a circuit which is
completed when an anode – the plating brush
– touches the component to be plated. This
allows the deposit to flow onto the negatively
charged part. This entire process is done
without the need to immerse the part in a
traditional plating tank. The deposit can be
applied accurately and reliably to very
localized areas without the need for postmachining.
Deposition rates are also up to 60
times faster than tank plating, further
minimizing downtime.
Plating portability.
Though it can be automated, selective
electroplating is an effective manual process
requiring minimal equipment – typically a
portable kit which can be easily carried to
facilitate the spot retouching.
Apart from portability and being able to
repair specific areas, the plating quality of the
SIFCO Process® is comparable to tank plating
in terms of performance, hardness and
adhesion. Just like traditional tank plating
methods, selective plating forms a
metallurgical bond to the base material. The
selective plating process can also deliver good
results on aluminum substrates that may
require ENP touchup.
An Electrolytic Nickel-
Phosphorus Option for Selective
Repair:
SIFCO ASC has a specially developed
coating - 5709 Nickel-Phosphorous – the
same plating alloy used in electroless nickel
plating. What is unique about 5709 Nickel-
Phosphorous is the ability of the plating
operator to adjust plating parameters to apply
different levels of phosphorus content
depending on the specific application. Thus,
with one plating solution, both low and high
phosphorous type coatings can be applied
depending on the desired surface
characteristics. When applied with a high
phosphorous content, the coating structure
changes from crystalline to amorphous,
resulting in a coating with superb corrosion
resistance properties.
Finally, the SIFCO Process offers a range of
environmentally safe alternatives. It also uses
less energy and produces less effluent waste
than tank plating, and brings considerable
environmental benefits too.
For operations committed to in-house
resources, the process can also be automated
to deliver consistent application during both
pre-treatment and plating. Data logging and
traceability can be added to the list of benefits.
An optimal solution.
Electroless nickel plating is an established,
effective and necessary process, improving the
corrosion resistance of components across
virtually all industry sectors. However, it is not
an ideal solution for repairs and retouching,
largely because for repairs, it requires the
removal and replating of the whole
component. This, in turn, adds time and cost
to operations.
As a tried and tested alternative, selective
plating with the SIFCO Process® delivers
ease, speed and convenience. Most
importantly, it creates a tough, corrosion
resistant finish on even the smallest areas,
preserving the function and integrity of the
component while minimizing downtime and
costs.
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Finishing - September/October 2021
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