WG: [meteorite-list] Preservation of iron meteorite

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Mon Nov 29 03:39:35 2004
Message-ID: <E5E6112EA31FA24CB448E091C6883C0517A71B_at_server2000.microfab.de>

Dear Taylor,

Sorry for my late reply. I'm not online on weekends.

> Will this work for iron?...

It is working! I have done this in the past with Toluca and Campo del Cielo specimens. The only disadvantage (beside the work involved) of the elecrochemical cleaning is, that present limonitic crusts are removed from the meteorites. I used already sliced specimens. They are quite stable afterwards.

Regarding the procedure you desribe: I would not recommend to use salt (NaCl) as it is exacly the chlorine, which you have to remove from the meteorite. It will not work very well this way. Only use NaOH or KOH solutions as given in the procedure (see link http://nautarch.tamu.edu/class/anth605/File10a.htm#ELECTROCHEMICAL). BTW: that's why it is not recommended to use HCl as etchant for iron meteorties. Better use HNO3 in alcohol (nital)

I must add that - from a SCIENTIFIC point of view, all the described measures are NOT ideal as they will affect the composition of the meteorite. It is a measure for very common, heavily corrosion sensitive irons or pallasites (e.g. Campo, Brahin, Toluca, Nantan...) For everything else, it is better just to keep the specimens very dry and - if available - add N2 or Ar inert gas. This will prevent rusting, but will not contaminate the meteorite or even attack contained mineral phases. In this sense, use of lacquers, corrosion inhibitors, oils etc. isn't a good measure for scientific valuable meteorites.

Cheers,
J?rn / MetBase

> -----Urspr?ngliche Nachricht-----
> Von: McCartney Taylor [mailto:mccartney_at_blackbearddata.com]
> Gesendet: Freitag, 26. November 2004 21:10
> An: Meteorite-list_at_meteoritecentral.com
> Betreff: [meteorite-list] Preservation of iron meteorite
>
>
> Jorn, I saw this posted by some coinshooters to clean metal. Will
> this work for iron? Haven't tried it. I suspect with some chem
> tweaks this may be the best your average collector could build
> affordably to treat irons.
>
> "When building a electrolysis machine to clean metal, a
> better transformer to use is an old AT type computer
> power supply not a ATX power supply just cut a yellow
> and a black wire from one of the four wire plug strip and
> attach clips. Yellow is POSITIVE (+), Black is ground.
> In a plastic tub mix tap water, a tablespoon of salt per 8 oz
> of water, attach yellow lead to a stainless steel piece put in
> water on one side of the bucket attach black lead to the
> metal find, put in the water on other side of bucket.
> Do not let the leads touch each other, turn on the power
> and it will bubble give it a little time and the dirt and rust
> will come off find and be on the stainless metal. The power
> supply does not over heat and cleans faster than small
> power supplies "
>
>
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Received on Mon 29 Nov 2004 03:40:07 AM PST