In article ,
Ned Simmons wrote:

On Fri, 28 Aug 2009 22:08:51 -0500, "Martin H. Eastburn"
wrote:

I find the pure water - attacks ? I don't think so.

DI water attacks copper and copper based alloys quite aggressively.
Austenitic stainless steels and nickel base alloys are generally OK,
though I have experience with Inconel immersion heaters corroding
surprisingly fast, even at relatively low temps (140F) in DI water.


Chlorine and such will. H2O is stable. If they have
electric current flowing in the pipes - possible - it can
break down H2O into hydrogen gas and oxygen gas.
The hydrogen will attack steel. The oxygen will attack
almost anything.

I bet they had a mixed iron and copper system and did themselves
in without using current breaks - plastic joints.

The absence of ions would rule out galvanic corrosion, no?

I'm not sure that deionized water is in fact free of ions, because the
beads used to fill the water treatment gadget are called ion *exchange*
beads or media. The implication is that they have traded one kind of
ion for another, not that all ions are removed.

Does distilled water attack copper et al? I would think not, because
copper stands up to rainwater pretty well.

Joe Gwinn