Relative Conductivity for Ag, Al, Au and Cu

The basic conductivity properties (thermal and elctrical) together with its inverse (resistivity) and respective prices and density have been obtained for Silver, Aluminium, Gold and Copper as follows. Note that prices are shown in USD per kg which results in somewhat unfamiliar values.

This results in the following relative conductivity values (Copper=100%). While on a volume adjusted basis, aluminium has about 60% of the conductivity (value may vary slightly as conductivity measurements are experimental and depend on the alloy type) on a weight adjusted basis, Aluminium has about double the conductivity of Copper. Finally on a price adjusted basis Aluminium's conductivity is more than eight times higher.

The situation for electrical conductivity looks very similar.

May be we read to much into the above but given the significant differential it is somewhat surprising that we are not seeing more substitution of copper by aluminium.