> Hi everyone.
> In the process of bringing up a 300 Mhz magnet we found severe corrosion
> on the aluminum base plate were it mates to the stainless steel can. The
> large Oring groove is mostly clean but the rest of the mating surfaces are
> severely corroded. Also this corrosion has atleast transfered itself to
> the stainless steel from which it is difficult to remove. Has anyone dealt
> with this problem before without having to replace the complete bottom
> plate. Any magic cleaning formulas perhaps? Any help would be greatly
> appreciated. Paul Bruins UC Davis.
This might be a common problem. Our magnet also has an aluminum base
plate attaching to a stainless steel can. Merck Index says aluminum oxide
is soluble in aq. alkaline solutions, but I know for a fact that NaOH also
dissolves aluminum metal as well. You can always use fine sandpaper to
rub it off (use carborundum, aluminum oxide is very hard). If the metal
is eaten up badly, I suggest you have the plate machined.
I for one, would rather go for preventing this corrosion in the first
place. I remember a previous post saying that the threaded holes on the
flange of the stainless steel can should be covered with silicone sealant
to prevent water from entering there. How effective is this? What about
the interface between the aluminum and stainless? Should this be caulked
as well? Has anyone else done a similar procedure?
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Edward T. Chainani Nuclear Magnetic Resonance Laboratory Manager
National Chemistry Instrumentation Center (NCIC)
Ateneo de Manila University phone: (632) 924-4601 loc. 2309
Loyola Heights, Quezon City e-mail: etch@ginto.chem.admu.edu.ph
Philippines
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