You are slightly off target on this one also. Metal hulled ships in
the oceans of the world form an electrical cell with the saltwater being
the electrolyte. A minor flow of electrons will leave the ship's hull
from areas determined by physical factors but generally aft in the
propulsion and rudder areas or in free flood areas of little
turbulence. The sacrificial metal is almost always zinc ingots (called
zinc anodes) are molded onto steel straps which are welded to the hull
or ingots of various forms with steel sleeved bolt holes meant to be
bolted onto the hull in the chosen area.
I suppose that aluminium could work for this but I have never seen or
heard of it my 25 years of marine engineering. For sure, that it
wouldn't last very long though. Mostly changing of sacrificial anodes
is done in drydock.
Rand E.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Yes, the oxidation is not much of a surprise to me. The rounds have been
> > lying in the fields (exposed to rain etc.) for several years. They seem to
> > have been made for the majority of a metal which contains iron (as they show
> > rust), probably this part is regular (or hardened steel), and something of a
> > light shade of metal, which most closely resembles aluminium. Now, supposing
> > this is aluminium, I seem to remember that (sea) ships use blocks of
> > aluminium as so-called "sacrificial metal", the idea is that aluminium is a
> > stronger reductor than the metal of the ship it self, causing the aluminium
> > to get oxidised rather than the ship (a simple yet effective trick) [I hope
> > I remembered all this correctly from my high school chemistry classes]. So,
> > it's not strange indeed to see that the tips of these bullets also got
> > oxidised.
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