Corrosion protection of petroleum oil well/tubing steel using thiadiazolines as efficient corrosion inhibitor: Experimental and theoretical investigation

• Published in: Surfaces and interfaces 2021-02, Vol.22, p.100770, Article 100770
• Main Authors: Tiwari, Nidhi, Mitra, Ranjeet Kumar, Yadav, Mahendra
• Format: Article
• Language: English
• Subjects: 15% HCl; Corrosion protection; N80 steel; Thiadiazolines
• ISSN: 2468-0230; 2468-0230
• DOI: 10.1016/j.surfin.2020.100770

Present investigation measures corrosion inhibition capabilities of thiadiazoline compounds; DFAT [2-4(difuran-2-yl-3-azabicyclo[3.3.1] nonan-9-yl-)-5-spiro-4-acetyl-2-acetylamino-1,3,4-thiadiazoline] and DIAT [2-4(di-1H indole-3-yl-3-azabicyclo[3.3.1]nonan-9-yl-)-5-spiro-4-acetyl-2-acetylamino-1,3,4-thiadiazoline] for petroleum oil well/tubing steel (N80 steel) in 15% HCl with the help of different techniques. The studied organic compounds show excellent corrosion mitigation properties with highest efficiency of 96.02% for DFAT and 97.05% for DIAT at a very small dosage of 50 ppm and 303 K temperature. Adsorption of both inhibitor molecules on the surface of N80 steel obeyed Langmuir adsorption isotherm. Potentiodynamic polarization studies revealed that both the compounds act as mixed type corrosion inhibitor and adsorb at the cathodic as well as anodic sites to mitigate corrosion process. The surface study was done through SEM, EDX, AFM, FT-IR and XPS analysis. The theoretical analysis (DFT and Monte Carlo simulations) of both inhibitors correlates the experimental findings.