A couple of branches down this particular rabbit hole:
I believe there is technique for dating artifacts made from multiple
metals (e.g. gold or silver filigree?) which depends on the mixing, or
alloying over long periods of time, while still in the solid phase.
There is a technique known as "ion beam alloying" which involves
bombarding the interface between to metals with an ion beam,
deliberately causing the atoms of each metal to be dislocated into the
other metal. The result being a bimetal becoming a trimetal (with a
thin sandwich layer of said alloy between purer versions of the other
metals)
I've also seen descriptions of this kind of mixing in the context of
molecular dynamics modeling and materials science, trying to understand
the degree and nature of such "spontaneous" mixing. Naturally the mixing
is much faster when in the materials are in a fluid state, but
apparently both crystalline and amorphous materials will mix
spontaneously over sufficient time when in contact (not surprising really?).
And then there is the Amalgam which is technically an alloy, but I think
the key difference is that the alloy is formed when one material is in
the liquid state (commonly mercury) and the other in a solid state
(aluminum inadvertently usually and silver intentionally for dental
fillings).
I think I see a few more branches down these side passages, but I'll
leave them alone for the moment.
- Steve
I think a solid 'dissolved' in another solid is an alloy, e.g. steel
(Fe and C), brass (Zn and Cu) tho' they have to be melted first. BTW
something funny happens with ethanol and water since they can't
ultimately be separated by distillation (let alone gravity fields)
because of the formation of an azeotrope
<http://en.wikipedia.org/wiki/Azeotrope>.
Robert C
On 7/8/12 6:59 PM, Arlo Barnes wrote:
The innocence of many of your questions as posed should be more
overtly valued... many of us are busy asking (quietly) similar
or related questions.
Amen!
A thing to think about re: mixing of alcohol and water is that both
are polar molecules, and thus mutually attracted, which no doubt
helps keep them from separating. However, since they are also equally
attracted to themselves, they could conceivably settle out were it
not for the aforementioned phenomena such as convection, et cetera. A
solution however (and I think no distinction is made about the states
of the materials [for example, the gas CO2 can dissolve in water to
form carbonic acid, the burning sensation felt when consuming
carbonated drinks], although it is hard to imagine a solid dissolving
in a solid) would need to be electrolytically separated, is my
understanding of the difference in definitions. The reason for this
is, taking the example of salt in water, is that the salt separates
into it's ionic components (for reasons unknown to me pending further
reading) which then would repel each other...or only the like-charged
ones would. Hm, I guess that too is pending further reading.
-Arlo James Barnes
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FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
