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

Influence of caffeine and temperature on corrosion-resistance of CoCrMo alloy

Manuela Romas, Anna Igual Munoz, Daniel Mareci, Carlos Valero Vidal, Silvia Curteanu, and Daniel Sutiman

Faculty of Chemical Engineering and Environmental Protection, Technical University of Iasi, 73 Prof. dr. doc. D. Mangeron Blvd., 700050, Iasi, Romania

E-mail: sutiman@ch.tuiasi.ro

Abstract: The inhibitory activity of caffeine (1,3,7-trimethyl xanthine) on artificial saliva was studied on a CoCrMo alloy using different electrochemical methods: open circuit potential (OCP), potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The results show that caffeine produces an inhibitory effect on the anodic currents due to its adsorption on the surface of the alloy. Temperature is another parameter with an influence on corrosion processes, so thermodynamic data were obtained from Arrhenius plots and Langmuir adsorption isotherms. The protective action of caffeine is enhanced at high temperatures at OCP, while for potentiodynamic experiments high temperatures block the inhibitory activity of caffeine and the corrosion rate increases. The process may also be studied by a simulation, determining the functional dependence between OCP, corrosion current density (i_corr), corrosion potential (E_corr), breakdown potential (E_bd) and temperature and amount of caffeine in artificial saliva, for Heraenium® CE. The neural network-based methodology applied in this work provides accurate results, thus proving to be an efficient modelling technique.

Keywords: CoCrMo alloy – caffeine – electrochemical analysis – inhibitory activity – neural networks

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-014-0549-3

Chemical Papers 68 (8) 1066–1078 (2014)