Corrosion Monitoring Of Galvanized Steel Under Chloride Rich Environment Using Potentiostat Testing

Azman, Nuramira (2021) Corrosion Monitoring Of Galvanized Steel Under Chloride Rich Environment Using Potentiostat Testing. Project Report. Universiti Teknikal Malaysia Melaka, Melaka, Malaysia. (Submitted)

Text (24 Pages) Corrosion Monitoring Of Galvanized Steel Under Chloride Rich Environment Using Potentiostat Testing.pdf - Submitted Version Download (397kB)

Abstract

Corrosion monitoring of galvanized steel (GS) is very crucial as it is one of the most widely used metals in the industry such as the oil and gas industry, where most of the critical pipelines are made of GS. This project was to study the corrosion behaviour of GS when exposed to chloride rich environment. In this study, sodium chloride (NaCl) solution was used to replicate the chloride rich environment. Three different concentration of NaCl solution which are 0.3 M, 0.5 M and 1.0 M and potentiostat testing was used to accelerate the corrosion process. The samples were prepared according to the standard ASTM G59-97. The samples were immersed in the 0.3 M, 0.5 M and 1.0 M NaCl solution at normal room temperature from 20 ℃ to 25 ℃ with a potential range of -0.5 V to 0.5 V and the scan rate of 0.5 mV/s. The immersion time was set to one hour for each concentration. The electrochemical region during the corrosion process of GS was studied from the potentiodynamic curve obtained. Furthermore, from the potentiodynamic curve, the corrosion potential (Ecorr), corrosion current density (icorr) and corrosion rate (CR) of GS were determined from the Tafel curve generated. The experimental results revealed that the sample of GS had the highest CR when immersed in 1.0 M NaCl solution while the lowest CR occurred in 0.3 M NaCl solution. Moreover, the surface morphology of the GS samples before and after the immersion was analysed using Scanning Electron Microscopy (SEM). The SEM analysis confirmed that the pit holes formed at the GS samples after the immersion in NaCl solution. The size of pit holes of the GS sample in 1.0 M NaCl solution was averagely larger compared to 0.3 M and 0.5 M NaCl solution. The SEM analysis proved that GS exposed to chloride rich environment was severely affected by corrosion

Actions (login required)

View Item