ABSTRACT
Studies on corrosion inhibition potential of Indigo Carmine extract on mild steel in acidic medium was carried out using weight loss and electrochemical techniques. It was observed that the Indigo Carmine extract retarded the dissolution of mild steel in the acidic medium. The corrosion rate decrease with increase in concentration. The CR decrease from 37.59mm/yr to 27.50mm/yr in presence of the inhibitor. The CR also increase with increase in temperature up to 60oC. The increase in CR with temperature suggests both physical and chemical adsorption of the Indigo Carmine (IC) on the mild steel. Potentiodynamic polarization measurements showed reduction in corrosion rate of mild steel surface. The potentiodynamicstudies shows a corrosion inhibition of 26.8% by the extract. Indigo Carmine was therefore found effective in inhibiting the corrosion of mild steel in acid medium.
TABLE OF CONTENTS
Contents
1.2 Causes and Economic effects of corrosion
1.3 Mechanism of corrosion inhibition
3.5 Temperature Dependence Measurements
3.6 Electrochemical Measurement
4.1 Effect of Inhibitor Concentration on Corrosion Rate
4.4 Electrochemical Measurement
5.0 CONCLUSIONS AND RECOMMENDATION
LIST OF FIGURES
FIGURE TITLE PAGE
1.1 Oil pipeline Corrosion - - - - - - 3
1.2 Gas pipeline corrosion - - - - - - 3
1.3 Inner view of corroded pipeline - - - - - 4
1.4 Corrosion in heat exchanger - - - - - - 5
1.5 Corrosion in heat exchanger - - - - - - 6
1.6 Corrosion in boilers. - - - - - - - 6
1.7 Stainless steel sheet before and after pickling - - - 9
4.1 Variation of corrosion rate (gcm-2h-1) with concentration of inhibitor - 19
4.2 Arrhenius plot for mild steel corrosion in Blank - - - 21
4.3 Arrhenius plot for mild steel corrosion in 10ppm Indigo Carmine - 21
4.4 Transition state plot for mild steel corrosion in Blank - - 23
4.5 Transition state plot for mild steel corrosion in 10ppm of Indigo Carmine - 23
LIST OF TABLES
TABLE TITLE PAGE
4.1 Arrhenius Parameters for the Inhibition of the Corrosion of Mild Steel 22
4.2 Value for thermodynamic Parameters calculated from Transition state
adsorption plot - - - - - - - 24
4.3 Table of values obtained from linear polarization measurement - 24