Nickel plating versus Chrome plating
Here are a few thoughts about plating. To properly electroplate
Chrome, it must be applied over an initial plating of either Copper
or Nickel. This is because of two reasons. (1) Chrome does not bond
well to iron. It bonds well to Copper or Nickel. (2) Chrome is not
impermeable. It is very thin and has microscopic cracks, so the
initial plating, much like a paint primer, seals the surface against
corrosion. Nickel and copper bond well to iron/steel and make a
complete impermeable protecting surface, bonded at a molecular level.
Nickel is the best undercoat for two reasons. (1)It is a close
cousin to iron, with similar molecular weight and magnetic structure.
and it is much harder than steel when electroplated slowly, and
allowed to form a dense crystalline atomic structure. It does
oxidize, but the yellow oxide protects the surface from further
corrosion, unlike iron which continues to corrode under the rust,
with consequent pitting.
(2)It is also relatively EPA safe, because the disposal problem is
minimal, since there is practically nothing to dispose of. The Nickel
anodes are used up and transferred to the work, and the electrolyte
is reusable indefinitely. Only the electricity is lost.
Copper is less desirable for two reasons, it may corrode green or black
through the cracks in the Chrome, and the best method of copper
plating, with a Cyanide compound, has become a serious EPA disposal
problem.
To sum up, IMO, Chrome is best with a good Nickel undercoat. What
the Chrome does is add a blue-white color over the yellow-white
color of the Nickel. Personally, I prefer the warm silvery brilliance
of Nickel over the cold blue-white color of Chrome.
The texture of the plating is wholly dependent on the texture of the
underlying surface. Even heavy plating is only a few thousandths thick,
and unlike paint, it cannot hide a rough surface.
For a polished brilliant surface, the steel must first be polished to
that same brilliance. This is usually more expensive because of the time
and labor involved.
For a matte or satin finish, sandblasting or wirebrushing develops the
texture, and the plating carries it through.
Everything I have explained here applies only to electroplated Nickel,
and does not apply to Electroless Nickel plating.
Electroless Nickel plating is achieved by a catalytic ion exchange
deposition process which does not necessarily assure the impervious
protecting bond and even distribution of the plating.
I do not do Electroless Nickel, because there is no need for it when
superior high quality electroplating is available. There is also a waste
disposal problem with Electroless Nickel plating. When the solutions are
depleted, a toxic waste remains, which can be a serious groundwater
contaminant.