Richard close, anodizing is simply a form of electroplating. Any metal
that conducts electricity can be anodized, the problem is the resulting
quality and usefulness. For the coating to be high quality it must have a
stable and durable surface to attach to.
Brass is a pure metal, just a combo of two and sometimes more, typically
simple shiny brass is composed of 75% copper and 25% zinc, aluminum and tin
are added to create stability and resistance to oxidation in very small
quantities.
Stainless steel is any number of metallic substances with a very low carbon
content, while containing a minimum of 10.5% chromium and often nickel and
molybdenum. The chromium reacts on the surface creating chromium oxide
which creates corrosion resistance and the stability and durability
required.
So they are definitely able to be anodized.
Patrick Bowen
-----Original Message-----
From: Richard B Gosling [mailto:Gosling_Richard_B@perkins.com]
Sent: Wednesday, November 29, 2000 12:51 PM
To: mikeginter; pbowen; spitfires
Subject: Re: Chrome or black trim ?? comment?
Patrick and Mike,
I disagree that all metals can be anodised. Anodising (UK spelling with s
not
z!) aluminium (UK again with extra 'i'!) takes advantage of the fact that
aluminium oxide is very stable, and bonds very well to the aluminium
underneath - the process uses electrolysis to encourage a layer of
aluminium
at the surface to oxidise. This protects the metal underneath (pure
aluminium
is very reactive), and also aluminium oxide can be stained, hence the
colour
can be applied. Hooray for my old A-level chemistry exam from 10 years ago
-
I haven't quite forgotten it all yet!
We all know, however, that iron oxide is NOT stable, or bonds well to the
surface - it goes yukky and brown and flakes off, because it is RUST!!
Therefore steel, which is mostly iron, CANNOT be anodised. Stainless steel
is
iron mixed with a little of another metal (don't know what), which
dissuades
it from rusting.
There may well be processes that give a similar effect to anodising on the
surface of steel, and I couldn't honestly say what is possible with brass
(particularly since that is not a pure metal) so I'll keep quiet on that
subject! It is possible that the word has become mis-used over time, to
describe processes that give a similar finish to anodising, but are in fact
completely different.
Richard and Daffy (who would look great, and rust-free, with a body made
entirely of anodised shiny aluminium!)
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