Use of Omeprazole as Inhibitor for C38 Steel Corrosion in 1.0 M H3PO4 Medium

Abstract

The importance of the use of various drugs as corrosion inhibitors has developed. In this context, the corrosion inhibition of C38 steel in 1.0 M H3PO4 medium by omeprazole has been evaluated by weight loss tests, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The surface morphology has been characterized by scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy. The Tafel polarization analysis shows that omeprazole is a mixed-type inhibitor. The results obtained by electrochemical impedance spectroscopy indicate that the inhibition efficacy increases with inhibitor concentration. The results obtained from the standard free energy of adsorption of $$(\Delta {G}_{\text{ads}}^{0}=- 37.86$$ kJ mol−1) are consistent with a physisorption and chemisorption process. The scanning electron microscopy allowed the visualization of a protective layer on the C38 steel surface after the addition of the inhibitor. The results obtained from different tested techniques showed excellent inhibition efficiency up to 99% using omeprazole for C38 steel in a phosphoric acid medium.