> > > >
> >
>snipped What most folks see as Chrome plating is AKA Triple Chrome Plating. It
> is a layered process. The part is ground and buffed to a high polish.
> However this surface may still have small imperfections. So it is plated
> with a layer of copper. This copper does two things, one it fills the
> imperfections and it conducts electricity better than the steel, both of
> which gives you a better and more even layer of plating. The part is
> then buffed again to a very high polish. (ANY imperfections must be
> taken out NOW) then the part is cleaned and plated in a nickel bath.
> Then it is buffed again and finally plated with a very thin chromium
> layer. The chromium layer is for wear resistance, it is the nickel that
> makes the finish bright and shiny. It wears pretty well BUT the
> copper/steel interface area is very fragile, any oil/rust or other
> contaminant will cause plating failure.
>
> Then you have "hard chroming" That is an entirely different process. In
> HC you polish the part to a finished size smaller than required and then
> plate chromium onto the part until it is built up over the required
> size, then ground and polished back to the correct spec.
>
> "Flashed" chrome is another different process that is done in a vacuum
> chamber and is basically vacuum deposited onto a surface that either
> doesn't conduct electricity or has a complex shape that plating in a
> tank cannot handle. (tight interior corners are hard to plate due to
> faradaic rejection in the tight angles. (same problem with powder coat > in tight areas)
>
> Hydrogen embrittlement is a real problem in high strength materials
> (steel, aluminum alloy,titanium alloys), subjected to high loading
> (suspension parts, stressed bars). The plating currents cause the
> hydrogen to be absorbed into the material and this weakens it. It is
> possible to correct the problem though. You need to follow each step of
> plating with a bake in the oven (375-450 depending on HRc of the steel)
> to remove the hydrogen from the item.
Isn't the steel nickel plated prior to the copper? (Xposted to a real metals group)