Corrosion problem happens in Cai Tau river water system; however, the mechanism is still questionable, resulting in unsolved ways. Therefore, this study focuses on the corrosion characterizations of carbon steel in Cai Tau river water system to analyze the corrosion mechanism using advanced electrochemical techniques and surface analysis. | Vietnam Journal of Science and Technology 55 (5B) (2017) 66-77 CORROSION CHARACTERIZATIONS OF CARBON STEEL IN CAI TAU RIVER WATER SYSTEM - VIET NAM T. K. N. Hoi1, N. D. Ho1, M. Vaka2, N. D. Nam1, * 1 Petrovietnam University, 762 Cach Mang Thang Tam Street, Ba Ria City, Ba Ria - Vung Tau Province, Viet Nam 2 School of Life and Environmental Sciences, Deakin University, Victoria 3220, Australia * Email: namnd@ Received: 11 August 2017; Accepted for publication: 11 October 2017 ABSTRACT Corrosion problem happens in Cai Tau river water system; however, the mechanism is still questionable, resulting in unsolved ways. Therefore, this study focuses on the corrosion characterizations of carbon steel in Cai Tau river water system to analyze the corrosion mechanism using advanced electrochemical techniques and surface analysis. Electrochemical results indicated that Cl‾ and SO42- ions shows a significant effect on corrosion of carbon steel, resulting in pitting corrosion. Whereas, carbon steel showed passive behavior when it immersed in solution containing CO32- ion. Furthermore, pH strongly affects the corrosion properties of carbon steel. It indicated that corrosion of carbon steel increased with a decrease of pH. Surface analysis was done to identify the surface area of the pitting corrosion of carbon steel. Corrosion rates, pitting and corrosion products were clearly observed and analyzed by optical microscopy and X-ray diffraction. Keywords: Cai Tau river water; Carbon steel; Corrosion; Activation; Passivation; Electrochemical techniques. 1. INTRODUCTION Nowadays, a lot of refineries and fertilizer plants are using direct water from the rivers, oceans to cool equipment in cooling water systems [1, 2]. The water may undergo different type of treatments to improve the quality through cooling system before use but, still it contains number of ions which may lead to corrosion problem in equipment [3, 4]. Water from Cai Tau river is used to cool steam turbine
