Abstract
Formation of protective iron carbonate films in $CO_2$ corrosion can reduce corrosion rate substantially and the effects have been incorporated in various prediction models. The $CO_2$ corrosion with the presence of free acetic acid is known to increase corrosion rate below scaling temperature. The possible interaction between the formation of iron acetate and iron carbonate films can affect the protectiveness of the film. The study is done using 3% NaCl solution under stagnant $CO_2$ -saturated condition at the scaling temperatures at various pH values and HAC concentrations. The result show that the presence of HAc does not affect the formation of protective iron carbonate film but delays the attainment of protective iron carbonate due to a possibility of solubilising of ferrous ions and thinning of the films.