The possible mechanism for inhibition has been debated on whether or not an existing corrosion scale
is required for inhibitors to adsorb onto the surface. Previous work1-3 has shown both conditions to be
true under certain testing conditions. This paper will demonstrate there is a synergistic relationship
between iron carbonate and a quaternized amine corrosion inhibitor to form a tighter more corrosion
resistant scale. This paper will explore the adsorption of quaternized amine during iron carbonate scale
formation through electrochemical and post-test microscopic analysis. There is evidence that
quaternized amines increase the precipitation rate of iron carbonate to enhance the already protective
passivation layer, which is the opposite that was observed in previous work where the inhibitor
prevented further iron carbonate from forming.