"NoSPAM" wrote in message
...
----- Original Message -----
From: "Sal M. Onella"
Newsgroups: rec.radio.amateur.antenna
Sent: Friday, November 07, 2008 11:20 PM
Subject: Aluminum to Copper interface


snip

2. I see a lot of brass and darn little corrosion. Would a transition
piece of brass be acceptable?

"Sal"

Red, yellow, and naval brass as well as aluminum bronze alloys are
marginally anodic with respect to copper so these alloys would provide
minimal corrosion protection. I know it might not be obvious, but steel
would make a better intermediate metal.

This will make sense if the actual voltages are included in the galvanic
series. These voltages are in sea water and with respect to a standard
calomel electrode.

Zinc -0.98
to -1.03
volts
Aluminum -0.70 to -0.90 "
Cast Iron -0.60 to -0.72
"
Steel -0.60
to -0.70
"
Red Brass, Yellow Brass, Naval Bross,
Aluminum Bronze -0.30 to -0.40 "
Copper -0.28 to -0.36
"

I saw those numbers decades ago -- in chem class, I guess. I cited brass
only because it seems to resist corrosion well, not because I actually know
what I'm talking about. g

73,
"Sal"
(actually KD6VKW)