brassing copper

I once read about using a strong alkali on copper to put a finish on it that wouldn't corrode. Has anyone seen or done this?

A hydroxide rubbed on cooper wouldn't put any zinc or chromium on the surface of the copper, so I wonder what this process was.

Seems to me that it would be useful whenever copper pipes are left visible.

David

I am not a metalurgist, so I am just throwing this out: there is a process called passivating, where a chemical is used to cause an oxide coating on the surface of metal. The coating inhibits further corrosion. The dark color which develops on exposed copper pipes is an oxide, and I think it does prevent further corrosion.

A classic example is Aloha stadium outside of Honolulu. It was built in the 70's. It is basically a steel structure, and the weather there would not normally be kind to steel; but the metal has a special treatment which caused it...over the first few years....to develop a classic reddish patina, and thenceforth no further corrosion occurs. It requires no paint, which would have been a full time process as it is on the Golden Gate bridge.

finish

It is probably Corten steel which is the same material that the Chicago "baboon" is made of, as well as the Hancock's exteror structure.