Conduction through surface films on aluminum wire

Conduction through undisturbed surface films on commercial aluminum wire is experimentally evaluated by establishing an area of contact on the wire surface without applying mechanical pressure, using a conductive silver epoxy. The measurements indicate the film conduction is substantially higher than has been estimated on the basis of the properties of pure aluminum oxide. Using applied electrical conditions similar to those of building wire applications, the potential drop is measured to be the same magnitude as is observed in failing aluminum wire connections. The results show that the behavior of failing aluminum connections can be accounted for by the conduction and breakdown properties of the surface film, in the absence of mechanically induced metallic asperity junctions.<>