International Journal of Advancements in Research & Technology, Volume 3, Issue 11, November-2014 ISSN 2278-7763 Copyright © 2014 SciResPub. Study of the Influence of Amorphous Tricalcium Phosphate on Corrosion Inhibition of Mild Steel in Hydrochloric Acidic Medium 1M Hassan Elaidi 1 , Ilham Ismi 1 , Elhosseine Rifi 1 , Mouhsine Galai 2 , Rachid Touir 2 , Mohamed Ebn Touhami 2 , Zineb Hatim 3 1 Laboratoire de synthèse organique et procédés d’extraction, Université Ibn Tofaïl, Faculté des Sciences , Kenitra, Maroc 2 Laboratoire d’Electrochimie de Corrosion et d’Environnement, Université Ibn Tofaïl, Faculté des Sciences , Kenitra, Maroc 3 Laboratoire d’Electrochimie et Traitement de Surface, Université chouaib doukkali, Faculté des sciences, El Jadida, Maroc Email: hassanelaidi@yahoo.fr ABSTRACT In this study, the inhibition effect of amorphous tricalcium phosphate (TCPam) on mild steel corrosion in 1.0M HCl solution was studied. For this aim, electrochemical techniques such as potentiodynamic polarization curves, weight loss (WL) and elec- trochemical impedance spectroscopy (EIS) were used. It was shown that, the amorphous tricalcium phosphate (TCPam) acts as a good inhibitor for mild steel corrosion in 1 M HCl solution. Its inhibition efficiency increased with concentration and reaches 87 % at 5×10 -6 M, and decreased with temperature and immersion time. Polarization measurements indicated that TCPam acts as mexed type inhibitor. In addition, Mechanism of physical adsorption is proposed from the apparent activation energy (Ea). Keywords : Amorphous Tricalcium Phosphate ;TCPam; Corrosion and Inhibition; Acidic medium, EIS 1 INTRODUCTION RON and its alloys find utility in a wide spread spectrum of many industrial units because of its low-cost and excellent mechanical properties. For this reason, the corrosion behav- ior of these materials has attracted the attention of several in- vestigations. The mild steel has many industrial applications because of its easy availability, uncomplicated fabrication of it into water pipe lines [1- 2], cooling water systems [3], boilers etc. However, they are susceptible to different forms of corro- sion inducted by chloride and so on. Steel is the most corro- sion vulnerable metal. Thus, much attention is given for its protection from the hostile environments. Acid solutions are widely used in industry. The most important areas of applica- tion are acid pickling, industrial acid cleaning, acid descaling, and oil-well acidizing[4–9]. HCl solution is one of the most widely used agents for these goals. However, iron and its al- loys could be corroded during these applications which result in a waste of resources. Corrosion prevention systems favor the use of chemicals with low or no environmental impacts. The reduction in the corrosion rate of metals has numerous advantages such as saving of resources, economic benefits during the industrial applications, increasing the lifetime of equipment and decreasing the dissolution of toxic metals from the components into the environment. Therefore, inhibitors are commonly used to minimize metal dissolution and acid consumption. Various types of organic compounds are widely used as corrosion inhibitors for protection materials against corrosion deterioration [10]. A perusal of the literature on acid corrosion inhibitors reveals that most organic substance em- ployed as corrosion inhibitors act by adsorption on the metal surface. Most of the efficient inhibitors used in industry are organic compounds which mainly contain oxygen, sulphur, nitrogen atoms and multiple bonds in the molecule through which they are adsorbed on metal surface [11–19]. In recent years, the méniral inhibitors have attracted more attention for their excellent corrosion inhibition performance. These prod- ucts dissociate in solution and it is their dissociation products that ensure the phenomena of inhibition. The aim of this study is to investigate the inhibition effect of amorphous tricalcium phosphate (TCPam) on the mild steel corrosion in 1.0 M HCl solution using weight loss and electrochemical measurements. 2EXPERIMENTAL DETAILS 2.1 Materials The steel used in this study is a mild steel (MS) with a chemical composition (in wt%) of 0.21 % C, 0.38 % Si, 0.05% Mn, 0.05 % S, 0.09 % P, 0.01 % Al and the remainder iron (Fe). For weight loss tests, the rectangular coupons with the size of 3,7 cm × 1 cm × 0.2 cm were used. A columned mild steel specimen, embedded in Teflon holder using epoxy resin with an exposed area of 1 cm 2 , was used as the working electrode for electrochemical measurements. The coupons and elec- trodes were abraded with emery paper (up to 1200 grit), cleaned with acetone and washed with distillated water, and finally dried at hot air before being immersed in the acid solu- tion. The aggressive solution (1 M HCl), used as blank, was prepared by dilution of analytical grade 37%. The concentra- tions of inhibitor were ranged from 10 -6 to 10 -4 M. The inhibitor used was an amorphous tricalcium phosphate (Ca3 (PO4)2 n I 74 IJOART