NVESTIGATION ON N-FORMYL PIPERIDIN-4-ONES AS CORROSION INHIBITORS FOR CARBON STEEL IN ACID MEDIUM

The corrosion inhibition of mild steel in 1N HSOand 1N HCl in the presence of N-formyl piperidin-4-ones was 24 studied using gravimetric and electrochemical techniques. Results obtained show that these compounds are excellent inhibitors and inhibit better in HCl than in HSO. The potentiodynamic polarisation studies clearly reveal that they are 24 mixed type inhibitors. The impedance parameters (R and C) clearly indicate the adsorption of N-formyl piperidin-4-ones ctdl on the metal surface leading to the formation of a protective layer which grows with increasing exposure time. The adsorption of N-formyl derivatives on mild steel surface in both the acid media follows a Langmuir adsorption isotherm and Tempkin adsorption isotherm. The mild steel-FP complex layer formed at the metal surface was identified by infrared spectral analysis and SEM/EDS.