This study presents the corrosion inhibition assessments of rose myrtle leaf-extract on mild steel surface in HCl 1M solution. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods have been used to study the corrosion behaviors of mild steel. The corrosion rate, corrosion current and corrosion potential results indicate that only small amount of the leaf-extract (2 % vol.) was required for high inhibition efficiency (Hin = %). | Vietnam Journal of Science and Technology 56 (3B) (2018) 63-70 ELECTROCHEMICAL BEHAVIOR OF MILD STEEL IN HCL 1M MEDIUM WITH THE PRESENCE OF ROSE MYRTLE LEAVES EXTRACTION Vo An Quan1, *, Nguyen Tuan Anh1, Tran Thi Ha2, Le Xuan Que1 1 Institute for Tropical Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi 2 Insitute of Chemistry, Biology and Special document technique, 47, Pham Van Dong, Cau Giay, Ha Noi * Email: vaquan@ Received: 23 July 2018; Accepted for publication: 8 September 2018 ABSTRACT As the growing interest on green corrosion inhibitors, plant extracts have gradually showed the potential in replacing the traditional hazardous chemicals due to the eco-friendly and economy characteristics. Previous study reported that rose myrtle leaf-extract (Rhodomyrtus tomentosa, Myrtaceae) was as an efficient corrosion inhibitor for rust removal process of mild steel in H2SO4 acid medium. This study presents the corrosion inhibition assessments of rose myrtle leaf-extract on mild steel surface in HCl 1M solution. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods have been used to study the corrosion behaviors of mild steel. The corrosion rate, corrosion current and corrosion potential results indicate that only small amount of the leaf-extract (2 % vol.) was required for high inhibition efficiency (Hin = %). By affecting on both anodic and cathodic branches of the Tafel plot, the corrosion inhibition mechanism is proposed by an adsorption forming different barriers on the steel surface. Keywords: green inhibitor, Rhodomyrtus tomentosa, steel corrosion, EIS. 1. INTRODUCTION Plenty of plant extracts have been reported to be acceptable corrosion inhibitors for metals in many types of corrosive medium [1, 2]. Basic components of extracts are sugars, steroids, aloin, gallic acid, ellagic acid, tannic acid, flavanoids, etc. The presence of tannins, cellulose, and polycyclic compounds has been reported to .
