"The Wanderer" wrote in message


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.

I somehow doubt that a change of porential of a few milliamps is likely
to be of great concern with overhead cables.

I heard sometime ago that highly polished faces of silver and gold
blocks can -if placed one on the other, weld together.

The first arc lamp produced by Priestly or someone from that era, was
powered from a bank or battery of copper and silver coins with sulphuric
acid electrolyte.

Zinc oxidises in air giving off some sort of electronic pulse when
struck by photons (or whatever light is.)

Torch batteries were originally zinc containers with a carbon core
separated by a paste made with some sort of acid. This developed through
platinum reduction of ethanol in satellites, into the modern watch
battery.

And a piece of aluminium rubbing up against a piece of iron will
eventually become inert due to layers of salts and oxides inhibiting
contact. Either that or they will rust apart.



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