Jake,
 
The issue of electrolysis softening ferrous metal is interesting. I am not  a 
metallurgist, so I do not have an answer. But I do know that heating 
different  metals and cooling them in materials such as a box of fine charcoal, oil, 
sand,  or soda ash will do different things to metals. I distinctly recall 
working  brass and copper and dipping them in oil and sand for certain effects. 
Copper  softened so that it could be easily hammered, then got brittle and the 
process  had to be repeated. I expect someone will come up with the answer to 
your  riddle, but just wanted to drop this memory into the pot.
 
Ron May
Legacy 106, Inc.
 
 
In a message dated 4/11/2008 11:01:34 P.M. Pacific Daylight Time,  
[log in to unmask] writes:

Hello  all,

Although I don't have anything to contribute to the discussion  of
brass corrosion, I thought this would be a good time to ask a  general
question re: corrosion, electrolysis, and the structure of  metals.

I've recently put together a small-scale electrolysis set-up  and have
been playing around with it for the last few weeks (with  materials
recovered archaeologically as well as random other metals for  fun).
One observation I've made concerning cast iron that really  intrigues
me is, for lack of a better word, a "softening" of the iron  following
electrolysis.  Once the iron has been dried under heat, the  cast iron
seems to return to its pre-electrolysis  hardness.

Hopefully my description makes sense.  Does anyone on  the list know
what is occurring chemically to the iron during electrolysis  to cause
this apparent shift in rigidity?  Please be as technical as  you like.

Best wishes,
Jake

-- 
Jakob  Crockett

Department of Anthropology
University of South  Carolina
Hamilton College, Room 317
Columbia, SC  29208

http://mannsimons.freehostia.com





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