[rotorwrench]

A lot of metals can be used as conductors but some are definitely better than others. It's all about resistance or the need for very low resistance levels. The longer a conductor the higher the resistance. Steel and other ferromagnetic related alloys do OK but corrode easily as already mentioned. Aluminum and copper are the least expensive of the metals that make good wire. Silver and gold are much better but obviously much more expensive. The alternate is to plate wire with tin, silver, or gold to reduce contact resistance. With gold being so very expensive, it is limited to plating for terminal pins and sockets so as not to break the bank. Aluminum wire has to have a larger cross section gauge to replace copper but it is used a lot in power transmission wires we see on the side of the road every day. Aircraft wire is available in silver plated copper for better conductivity or tin plated copper for better corrosion resistance. Copper is king in the automotive business with tin plated copper as a more expensive alternative to bare copper.