I am rebuilding the 6m antennas. I was going to use stainless steel nuts/bolts to make connection from feedline to driven element. On a whim, I looked up conductivity. When I found this, I decided to purchase aluminum nuts/bolts for these critical connections.
This is what I found on the internet:
Silver has the highest electrical conductivity. followed closely by copper, then aluminum, while stainless steel is a poor conductor.
Conductivity is often measured in % IACS (International Annealed Copper Standard), where silver is ~105%, copper 100%, aluminum ~61%, and stainless steel only ~2.5%