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From: beckenba@cit-vax.Caltech.Edu (Joe Beckenbach)
Newsgroups: sci.research
Subject: Re: Superconductors
Message-ID: <4405@cit-vax.Caltech.Edu>
Date: Wed, 4-Nov-87 04:09:06 EST
Article-I.D.: cit-vax.4405
Posted: Wed Nov  4 04:09:06 1987
Date-Received: Sat, 7-Nov-87 08:47:38 EST
References: <691@tahoe.UUCP>
Reply-To: beckenba@cit-vax.UUCP (Joe Beckenbach)
Organization: California Institute of Technology
Lines: 39
Keywords: Superconductor do-it-yourself

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	The latest issue of OMNI magazine (November 1987, page 72+) has an
article on how to make your very own batch of Y1Ba2Cu3Ox liquid-nitrogen
superconductor. To make "123", as it's called, combine 1 part yttrium oxide,
2 parts barium carbonate, and 3 parts copper oxide. Grind to powder, bake at
900-950C for 12 hours. Cool in kiln, regrind, and compress the powder at
15000-18000 pounds in a hydraulic press. Rebake in oxygenated kiln, let cool
very slowly (minimum 8 hours). You now have a fragile superconductor which
crumbles on absorbing moisture.
	As author Bruce Schecter points out:
	"Please remember, recipes are rarely complete. The experienced chef
knows this and fills in missing steps unconsciously. The same is true of 
laboratory recipes. The consequences of mistakes in the kitchen are only
unpalatable; laboratory mistakes can be dangerous, or even deadly. So have a
professional, such as a [good] science teacher, in the room while work is
being done."
	Three other notes:
	1) This was reproduced without permission, and so I had to leave out
some of the details of acquisition of materials and machines. I suggest 
that anyone interested in this sort of project buy up an issue of OMNI with
this article, order a reprint, or in some like manner acknowledge Mr. Schecter'sgood work.
	2) Caltech has the capacity to do this project, perhaps in conjunction
with the Secondary Students Project. As Mr. Schecter notes, this is one of the
best ways to incite the next generation to learn about science: hands-on
participation.
	3) A resounding "Amen" to the laboratory dangers warning: in my frosh
lab we made chips with 'large' transistors. The photoresist only smelled bad;
the hydrogen fluoride etch was the real nightmare-producer: the only thing
worse than one HF spill on a person would be one HF spill which was neither
washed thoroughly nor neutralized by calcium compound injections.
	On a similar note, an acquaintance in high school built a working model
of a volcano using gunpowder. He tried looking into it to see if the cycle was
starting. Luckily my sister kept her head when the thing spread itself over the
room: he kept his eyes thanks to that.
-- 
		-Joe Beckenbach (CS BS '88)
Note: Space colonies go outside the magnetosphere. It's war in the
Persian Gulf. I can't get a date for Saturday night. Oh, the horror! :-)