Mechanism of corrosion inhibition
It is well recognized that organic inhibitor molecules set
up their inhibition action via the adsorption onto the
metal/solution interface. The adsorption process is affected
by the chemical structures of the inhibitors, the nature
and charged surface of the metal and the distribution
of charge over the whole inhibitor molecule. The presence
of N, O, S atoms and conjugated double bonds in
the organic structures makes the formation of p–d
bonds resulting from overlap of p-electrons to the 3d
vacant orbital of iron atoms, which enhances the adsorption
of the compounds on the metal surface [23-25]. In
general, organic inhibitor molecules may be adsorbed
on the metal surface in one or more of the following
ways [26,27]: