General Information about Aluminum

Aluminum ranks second to copper in the commercial importance as an electrical conductor. Its conductivity is approximately 60 per cent of that of pure copper. Taken on a mass basis, the conductivity of aluminum is about twice that of copper. This, as well as a greater strength per unit weight, gives aluminum some advantage over copper as a conductor material when used as a long span of transmission cable.

The increased diameter of an aluminum conductor necessary to carry the same amount of current of an equivalent copper conductor tends to minimize corona losses and skin affect. This larger diameter, however, has a disadvantage since it offers a greater resistance to wind and storm owing to its larger area.

Aluminum is high in malleability and ductility and can consequently be rolled into sheets or drawn into wire with relative ease. it can be welded or soldered without too much difficulty provided a proper flux is used to retard the forming of a detrimental oxide film. Of the two processes soldering is the more difficult.

Similar to copper, aluminum is very resistant to deterioration through oxidation by the formation of an initial oxide film which prevents further oxidation. The protective coating of the oxide film is so effective that many aluminum parts to be subjected to various corrosive atmospheric conditions are given pre-oxidation treatment through an anodizing process. This oxide film presents difficulties where contact surfaces are to be made. Aluminum, however, is readily corroded when in contact with most metals in a moist atmosphere due to its highly negative potential. This type of corrosion is caused by a galvanic action in which the moisture, acting as an electrolyte, causes current to flow through the contact of the two metals while an electron transfer causes the aluminum to go into solution.        

Physical Properties of Aluminum

Hard Drawn