What is the area of a magnetic material where individual atoms line up?
The bus bar bars and lugs are not aluminium they are Copper are and the copper is is treated, similar to the old VIR cables that used to be tinned, when they did away with VIR cables and changed to PVC cables they still tinned the copper conductors for a while before it dawned on some on it was a waste of time doing that with PVC insulation. Brass reacts with with aluminium so that when you gland aluminium cable you have to use aluminium glands and bannjos, Aluminium cables are hardly used now although you get aluminium armoured with copper cables is used a lot with large as it is lighter than steel wired armoured to install.
Previous poster has an excellent answer. I would only add that the reason there is a better mechanical connection is also due to teh softness of the aluminium
