In this paper the effect of green inhibitor, prepared from aqueous extract of Paronychia Argentea, on calcium carbonate deposition onto steel surface was investigated. The experimental chronoamperometric curves of nucleation growth process of calcium carbonate that exhibit delay when green inhibitor was added were successfully reproduced by the associated modeling work which solved the convectivediffusion equation to calculate the limiting current of Oxygen Reduction Reaction at a Rotating Disk electrode. (C) 2015 Elsevier Ltd. All rights reserved.