Effect of Electrode Geometry and Size on Electrochemical Corrosion Rate Measurement Method

• Main Author: Kosasi, Herman
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/38034
• Institution: Institut Teknologi Bandung

Corrosion is a degradation process of the metal as a result of interaction of metal with environment. Some methods that used to minimize the rate of corrosion are passivation, coating, and the addition of corrosion inhibitor. To determine the rate of corrosion of the metal or the performance of corrosion inhibitor, it requires corrosion rate measurements which are practical and reliable. Electrochemical methods of corrosion rate measurements (Electrochemical Impedance Spectroscopy and Tafel) have some advantages in efficiency measurement time and its sensitivity level. Corrosion inhibition rate was influenced by temperature, variations in the concentration of the inhibitor, the distance between the working electrode and auxiliary electrode, as well as the comparison of the size of the working electrode and auxiliary electrode. Corrosion rate of electrochemical method was measured using three electrodes to produce reliable results need to be assessed with the effect of size, the geometry of working electrode and auxiliary electrode. The working electrode that we used in this study was carbon steel ,graphite as auxiliary electrode, and saturated calomel electrode as reference electrode. In this study, corrosion rate of carbon steel in NaCl 1% was measured electrochemically by varying size and distance of working electrode between auxiliary electrode without cysteine inhibitor and cysteine inhibitor addition at 65 .Weight loss method was used to compare the result with both electrochemical methods. In this study, corrosion rate inhibition by varying temperature, concentration of inhibitor, distance of two electrodes, and electrodes size was measured. The size of the working electrode and auxiliary electrode that we used were 6 mm, 8 mm, and 10 mm. Size of the working electrode and auxiliary electrode that we used were 8 mm, 10 mm, and 12 mm. Experimental results showed that cysteine inhibitor is suitable for use at weight loss method and electrochemical methods. Weight loss method showed the highest value % inhibition efficiency and the lowest corrosion rate at 67.1% and 1.089 mm/year at 65 and the addition of cysteine as much as 20 ppm. Electrochemical Impedance Spectroscopy method showed the highest value % inhibition efficiency and the lowest corrosion rate at 90.9% and 0.334 mm/year on the size of the working electrode 6 mm, 10 mm auxiliary electrode, at distance of 8 mm, and the addition of cysteine as much as 30 ppm. Tafel method showed the highest value % inhibition efficiency and lowest corrosion rate at 92.1% and 0.186 mm/year on the size of the working electrode 8 mm, 10 mm auxiliary electrode, at distance of 8 mm, and the addition of cysteine as much as 25 ppm. It can be concluded that the greater the size of the auxiliary electrode and the second electrode close distance, it would produce corrosion rate measurement results that are easier to prepare and reliable.