Corrosion Inhibition of Monel 400 in 1M HCL Using a Novel Eco Inhibitor Curcumin and Bis Curcumin Bis Azodye

Abstract

Corrosion inhibition of Monel 400 in 1M HCl using new synthesis environmentally friendly compound bis curcumin bis azodye (BCBAD) was studied. BCBAD was prepared via diazotization of p-phenylenediamine and coupling bimolar ratio of 1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (curcumin). Structure of the new dye BCBAD was checked and confirmed by Nuclear Magnetic Resonance (1H-NMR), Fourier-Transformer Infrared (FTIR) spectroscopy and Mass-spectrum. Potentiodynamic polarization and cyclic polarization Techniques were carried out to evaluated effect of curcumin and BCBAD on the electrochemical behavior of Monel 400. Tests in five concentrations 25,50,100,150 and 200 ppm in 1M of HCl were studied. Results showed that corrosion rate of blank was 18.576 mpy, curcumin with the best concentration 150 ppm was 4.51 mpy with 76% efficiency and the best concentration 200 ppm of BCBAD was 0.957mpy with 95% efficiency. Thus, BCBAD was performed as an excellent inhibitor. The protective layer formed by curcumin consists mainly of Cu(OH)2·H2O, with an average thickness of 27.33 µm and average protective layer thickness which consisted of Fe2N and CuO using BCBAD was 44.13µm. Adhesion of curcumin was classified according to ASTM D3359 method B was (1B) where BCBAD was (3B).