TechNetters, to add a bit of information to Paul's posting, the chlorine
that reacts with aluminum is not consumed in the process, so even the
smallest amount of chlorine will eventually destroy the capacitor.  Aluminum
hyroxide forms, which is soluble in water, and chlorine returns to start the
reaction again.  Lou Hart

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Paul
Signorelli
Sent: Tuesday, July 01, 2003 2:37 PM
To: [log in to unmask]
Subject: Re: [TN] Leaky capacitors


i have seen that before,
could be electrolyte leakage or possibly precipitate from cleaning with
halogenated solvents.
Aluminum Electrolytics are corroded by Halogenated (like Cl) solvents,
what kind of solvent did it see ?
Solvent infiltrates capacitor through rubber seal and Chlorine reacts
with aluminum inside cap, causes latent failures.
It could also be surface dendrites from trapped moisture or electrolyte
leakage.
High heat in area or high ripple current will cause the reaction to
become faster.
Paul Signorelli

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