A STUDY OF THE CORROSION INHIBITION OF CARBON-STEEL IN DILLUTED AMMONIA MEDIA USING 2-MERCAPTO-BENZOTHIAZOL (MBT)

Adriana Samide,^a,* Ion Bibicu,^b Mircea Rogalski,^c and Mircea Preda^d

^a Faculty of Chemistry, University of Craiova, 165 Calea Bucureşti,1100 Craiova, Romania

^b National Institute of Materials Physics, Bucharest 76900, Romania

^c Physics Department, Instituto Superior Tecnico, Av. Rovisco Pais 1040-001 Lisbon, Portugal

^d Faculty of Chemistry, University of Craiova, 165 Calea Bucureşti,1100 Craiova, Romania

Abstract

The inhibiting effect of MBT has been studied regarding the corrosion of carbon-steel in diluted ammonia solution at room temperature. The effects of the inhibitor have been demonstrated using weight loss and electrochemical measurements. The increase of the inhibitor concentration leads to a decrease in the corrosion rate and in the corrosion current. The microscopic analysis of the surface of the electrode shows a decrease of the corrosion spots with the increase of the MBT concentration. This indicates a good adsorbability of MBT on the metal surface. Mössbauer spectrometry shows the formation of a superficial film on the surface of the corroded sample in the presence of MBT. This film provides a good corrosion protection for the sample.

Key words: carbon-steel, ammonia media, inhibitor, MBT, Mössbauer spectrometry