Cadmium would actually be a poor choice for rustproofing iron since it
has a lower redox potential (0.402 V). This means that it would oxidise
after iron (0.44 V). Aluminium (1.677 V) and zinc (0.762 V) would be
better choices with zinc being the better choice of the two. Does it
really matter which metal was used? As far as a simple test goes, zinc
and aluminium will give very similar results to tests that one could
easily get the reagents for (i.e. hydroxide, both will give a white
precipitate). In truth, they're a pain in the butt to distinguish. The
oxides of both will be white, so you can't tell them apart that way
either. To actually test for it you would need to scrape off some of
the coating and then dissolve it in some acid (pref. HCl since nitric
can interfere with things) and then combine with some reagent. To get
enough to perform a qualatative analysis (i.e. no machinery) you'd
probably have to scrape for a while, and removing the coating would be
rather counterproductive. So unless its imperative that you know what
metal is there, and have access to a chem lab, I don't think its really
worth worrying about.
James
"A. Foster" wrote:
>
> Dick;
> They likely used anodization or electroplating to coat the bare steel with
> aluminum and the publicity people just cooked up the term,"Aluminized". It
> is likely that the sheet metal was plated before they punched panels out of
> it to stop it from rusting in storage. I have run into similar plated metal
> in my car on the clock housing and the radio cabinet, both of which would
> have been better painted. Of course I don't know whether it is aluminum or
> zinc or even cadmium, which was what some radio chasis' were plated with, or
> how you would tell the difference unless it's oxidized. Perhaps there is a
> chemist out there who could devise a simple test for us?
> What is interesting is that in the 73' Imperial profit book, that is on the
> main site, they mention that the door sills are galvanized which is usually
> a coating of zinc. They also mention dipping the body in a phosphorus
> solution for rustproofing and later dipping it in primer. Maybe if someone
> can find a 67'/68' profit book they could tell you what this plating was
> for? If it were me I would paint the underside of this shelf just for
> security, I am sure that the lack of paint was by error and not by design. I
> do know that I have seen a number of C-bodied cars around town and they
> always rust in the same same places so this aluminum plating didn't help
> that much.
> Best Regards
> Arran Foster
> 1954 Imperial Newport
> Needing A left Side Taillight Bezel and other trim parts.
>
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