doozer wrote:

I am curious. What could you possible want to install for 150 to 200 years?

I would imagine given that amount of time dissimilar metals will corrode
significantly. Probably to the point of failure. Is it vital that they
are dissimilar metals and that they are irreplaceable for 150 years?

Aluminium is an interesting case because it is actually a highly
reactive metal* but in the presence of oxygen it forms a tough oxide
(rust) coating that stops further reaction. Perhaps as long as you don't
continually damage that coating (e.g. they joint is completely
immobile) it might last quite well.


Trouble is al oxide is fine to protect against pure water, but any
acidity and ist gone. Salt likewise.


Its very interesting to visit old museums and see the occasioanl iron
age sword, as a rotted sump, but almost perfect bronze swords...iron
doesn't last AT ALL well.

Most of the early cast and wrought iron stuff is on the edge of
destruction and needs painting everyt year.

*You would be amazed at the speed of the reaction. I have seen aluminium
foil nearly catch alight after it has had the oxide coating removed by
chemical treatment.