Inhibition effect of rosemary oil on mild steel corrosion in a water-based petrochemical drilling fluid

Abstract

Corrosion inhibition of carbon steels applied in water-based petrochemical drilling fluid solution (DFS) with non-toxic chemical compounds is an important focus of research. Rosemary oil (ROS) was evaluated for its corrosion inhibition effect on mild steel (MS) in DFS by the potentiodynamic polarization technique and optical microscopy characterization. The corrosion rate data show that ROS effectively inhibited MS corrosion with an average inhibition efficiency above 90%. ROS displayed anodic type inhibition mechanism. The polarization curves displayed the passivation region, which signified the total surface coverage of MS surface. Morphological images of inhibited MS surface significantly differred from the control MS without ROS, whose surface was severely deteriorated by corrosion pits and grooves.