ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Effect of hyamine on electrochemical behaviour of brass alloy in HNO₃ solution

Demet Özkır, Emel Bayol, A. Ali Gürten, Yavuz Sürme, and Fatma Kandemirli

Department of Chemistry, Faculty of Arts and Sciences, Nigde University, 51100, Nigde, Turkey

E-mail: dozkir@nigde.edu.tr

Abstract: The electrochemical behaviours of a brass alloy in 0.1 M nitric acid, including the hyamine inhibitor with concentrations between 2.5 × 10⁻⁴ M and 1.0 × 10⁻⁵ M, were studied. For this purpose, potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR) techniques, and flame atomic absorption spectroscopy (FAAS) were utilised. The inhibitor molecules adsorbed on the brass surface were calculated to be in good agreement with the Langmuir adsorption isotherm and the standard free enthalpy of adsorption (ΔG_ads^°). Hyamine effectively improved the corrosion inhibition of brass and acted as a mixed-type inhibitor on alloy surfaces. The surface morphology of the alloy was also clarified by optical microscopic and SEM techniques. A theoretical study of the corrosion inhibition efficiency of hyamine molecule was carried out using density functional theory (DFT) at the B3LYP/6-311G(d,p) basis set level.

Keywords: electrochemical techniques – computational techniques – dezincification – acid corrosion inhibitor – brass

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-012-0255-y

Chemical Papers 67 (2) 202–212 (2013)