AW: [meteorite-list] Is Brahin a ruster ?

From: Jörn Koblitz <koblitz_at_meteoritecentral.com>
Date: Tue Feb 8 08:02:34 2005
Message-ID: <E5E6112EA31FA24CB448E091C6883C052E5EAA_at_server2000.microfab.de>

Hi List,

back in the 1980s, I got a large, beautiful Admire slice. I kept it at low humidity and also added corrosion inhibitor to the bag in which the slice was wrapped in. During the first 10 years I checked for signs of rust from time to time. It was okay, no rust, very stable. So, I kept it alone (same storage conditions) until one year ago, when I look at it again. Well, the pallasite was in the state of disintegration, heavily rusted, olivines pressed out of the metal grid. What I want to say is, that even after so long time of stability, one can never be sure. I think, one has to check the state of such a known ruster more often. If any sign of rust, especially swallowing of olivine grains, one has to start corrective actions immediately (e.g. neutralization of acids, drying...). Rusting is a self-accelerating process, once it has started. If a meteorite is known as a ruster (like Brahin, Brenham, Admire), be very careful!

I am presently developing a special method of treatment to remove all the salts (the source of the mess) from such corrosion sensitive irons and pallasite specimens. I hope, with such reatment, then these rusters are sufficiently stabilized for the time being.

J?rn


> -----Urspr?ngliche Nachricht-----
> Von: Martin Altmann [mailto:Altmann_at_Meteorite-Martin.de]
> Gesendet: Montag, 7. Februar 2005 23:35
> An: Lars Pedersen; meteorite-list_at_meteoritecentral.com
> Betreff: Re: [meteorite-list] Is Brahin a ruster ?
>
>
> Hi Lars,
>
> Brahin is untreated a hefty ruster like Brenham.
> With two of the main suppliers of Brahin I made the experience
> that Afanasjev (cometshop) did a good job in varnishing his slices.
> My oldest slice from him I had for almost 7 years without any problems
> and many others I had in stock for 2years and more without
> developping a
> single trace of rust.
> Once I was curios, grinded off the varnish and the slice
> started to rust and
> to swell within a few weeks.
>
> >From the other supplier Koutyrev (finmet) I know only, that
> he advertized
> his slices in former times to be stabilized with a "new
> method" and with the
> gimmick, that you can keep them even in salt water without any effect.
> I never took from his Brahins, but heard from several of my collector
> fellows as well as from some dealers too, that they were
> indeed stable and
> goody-goody.
>
> To be sure, one should choose a member of the
> Eagle-Station-grouplet, with
> their 15%+ Ni, they should be the most stable ones among all
> pallasites, but
> they are difficult to get and not even cheap...
>
> Cheers!
> Martin
>
>
>
> ----- Original Message -----
> From: "Lars Pedersen" <lbp_at_privat.tdcadsl.dk>
> To: <meteorite-list_at_meteoritecentral.com>
> Sent: Monday, February 07, 2005 8:52 PM
> Subject: [meteorite-list] Is Brahin a ruster ?
>
>
> > Hello All
> > Thanks for you show reports and poictures, I enjoy them.
> >
> > I have just traded for a big fullslice of Brahin.
> >
> > Is it a ruster ?
> > How do I prevent ?
> > etc. etc. ?
> >
> > Best
> > Lars
> > --------------------------------------------------
> >
> > New meteorite forum:
> >
> > http://www.worldofmeteorites.com/
> > ______________________________________________
> > Meteorite-list mailing list
> > Meteorite-list_at_meteoritecentral.com
> > http://six.pairlist.net/mailman/listinfo/meteorite-list
>
> ______________________________________________
> Meteorite-list mailing list
> Meteorite-list_at_meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
>
Received on Tue 08 Feb 2005 08:04:13 AM PST