[meteorite-list] Etching Iron Meteorites

From: Drake <Monel_at_meteoritecentral.com>
Date: Wed, 31 Jan 2007 19:54:12 -0500
Message-ID: <01d101c7459b$7e555f00$7400a8c0_at_DADS>

I agree, "Zero". You could make nice Widmanstatten patterns in some
stainless steel alloys like 303, the giant crystals I've seen would be
virtually impossible and very expensive.

The dendrites seen in cast irons are the crystals growing along the
crystallographic planes as the metal solidifies. This is basically the
same property in metals that also form the Widmanstatten patterns. It's
also why snowflakes, and gemstones have their unique shapes; they are
all growing crystals taking on the shape of their crystallographic
planes, or atomic arrangement. (ie, salt is always a cube and an
amethyst is always a tetrahedron.)

Drake

Quis Custodiet Ipsos Custodes

Drake "Doc" Damer?u
President, NEPRA
NAR Section 614
L3CC member
TRA 9934 L3
 
www.nepra.com
www.rocketmaterials.org
http://home.sprynet.com/~monel/home.htm

 
 

> -----Original Message-----
> From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-
> bounces at meteoritecentral.com] On Behalf Of Martin Altmann
> Sent: Wednesday, January 31, 2007 7:21 PM
> To: 'Sterling K. Webb'; meteorite-list at meteoritecentral.com
> Subject: Re: [meteorite-list] Etching Iron Meteorites
>
> "What's the likelihood of fake meteorites being made that way?"
>
> Zero. You have to fake at least pallasites for the fraud becoming
> profitable
> q.e.d.
>
> Would be nice to have a photo of the described products, if they show
any
> similarity to Widmathompsopatures.
> (Cast irons display dendritic patterns).
>
> Martin,
> Frozen in Tucson.
>
>
> -----Urspr?ngliche Nachricht-----
> Von: meteorite-list-bounces at meteoritecentral.com
> [mailto:meteorite-list-bounces at meteoritecentral.com] Im Auftrag von
> Sterling
> K. Webb
> Gesendet: Donnerstag, 1. Februar 2007 00:43
> An: Drake; meteorite-list at meteoritecentral.com
> Betreff: Re: [meteorite-list] Etching Iron Meteorites
>
> Hi, Drake,
>
> > ...Widmanstatten patterns are unique to
> > meteorites. That's not true.
>
> I'll bite. In what other materials can they be found?
> Long considered definitive hereabouts. I quote one
> source: "Widmanstatten pattern or Thompson structure:
> This pattern does not appear in terrestrial iron ores.
> Its presence is diagnostic in the identification of a
> meteorite."
> Looking for a definition, I found that they form when
> "steels are cooled at a critical rate from extremely high
> temperatures. It consists of ferrite and pearlite and
> has a cross-hatched appearance due to the ferrite
> having formed along certain crystallographic planes."
> What's the likelihood of fake meteorites being made
> that way?
>
> Sterling K. Webb
> ------------------------------------------------------------
> ----- Original Message -----
> From: "Drake" <Monel at sprynet.com>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Wednesday, January 31, 2007 4:52 PM
> Subject: Re: [meteorite-list] Etching Iron Meteorites
>
>
> That was I, and thank you. The Nital I was using was what I use for
> standard metallographic sample preparation at 2% to 5%. I see now I
need
> a much higher concentration.
>
> I did find one metallurgical error in that it states that
Widmanstatten
> patterns are unique to meteorites. That's not true.
>
> Drake
>
> Quis Custodiet Ipsos Custodes
>
> Drake "Doc" Damer?u
> President, NEPRA
> NAR Section 614
> L3CC member
> TRA 9934 L3
>
> www.nepra.com
> www.rocketmaterials.org
> http://home.sprynet.com/~monel/home.htm
>
>
>
>
> > -----Original Message-----
> > From: meteorite-list-bounces at meteoritecentral.com
> [mailto:meteorite-list-
> > bounces at meteoritecentral.com] On Behalf Of Gary K. Foote
> > Sent: Tuesday, January 30, 2007 6:21 PM
> > To: meteorite-list at meteoritecentral.com
> > Subject: [meteorite-list] Etching Iron Meteorites
> >
> > Hello List,
> >
> > I forget who was asking this morning, but Ruben Garcia has
graciously
> > allowed me to
> > publish his in-depth article on cutting, etching and preserving iron
> > meteorites to my
> > site.
> >
> > For those interested the URL is;
> >
> > http://www.meteorite-dealers.com/etchingandpreservation.html
> >
> > Gary
> > http://www.meteorite-dealers.com
> > ______________________________________________
> > Meteorite-list mailing list
> > Meteorite-list at meteoritecentral.com
> > http://six.pairlist.net/mailman/listinfo/meteorite-list
>
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Received on Wed 31 Jan 2007 07:54:12 PM PST