What causes dealloying? Different metals and alloys have
different electrochemical potentials (or corrosion
potentials) in the same electrolyte. Modern alloys contain a
number of different alloying elements that exhibit different
corrosion potentials. The potential difference between the
alloying elements is the driving force for the preferential
attack on the more "active" element in the alloy. In the
case of dezincification of brass, zinc is preferentially
leached out of the copper-zinc alloy, leaving behind a
copper-rich surface layer that is porous and brittle.
