On Fri, 25 Feb 2005 16:43:32 GMT, Anna Kettle wrote:

If some stainless steel and some aluminium are left in contact then am
I imagining it or is there an electric current induced. Not much of
one of course, but if they are left for long enough then does some
metal transfer occur?

Electrolytic corrosion, it occurs when dissimilar metals are left in
contact in the atmosphere. In essence, you are creating a small cell or
battery, and with acid rain, small currents flow.

It was - and I suspect still is - a major problem in the electricity supply
industry where both copper and aluminium are used for overhead conductors.
Joints between the two metals are almost invariably where the faults occur.
unless special bimetallic joints, specially made for use in the particular
situation, are used. Before these were made, the remedy was physical
protection of the joint with grease and denso tape. Bimetallic joints have
now been in use for some 20 to 25 years at a guess, and I suspect these
will be about ready to start playing up, BICBW.


--

the dot wanderer at tesco dot net