%0 Journal Article
%T Corrosion and Inhibition Effects of Mild Steel in Hydrochloric Acid Solutions Containing Organophosphonic Acid
%A Manish Gupta
%A Jyotsna Mishra
%A K. S. Pitre
%J International Journal of Corrosion
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/582982
%X A study has been made on the mechanism of corrosion of mild steel and the effect of nitrilo trimethylene phosphonic (NTMP) acid as a corrosion inhibitor in acidic medium, that is, 10% HC1 using the weight loss method and electrochemical techniques, that is, potentiodynamic and galvanostatic polarization measurements. Although corrosion is a long-time process, but it takes place at a faster rate in the beginning which goes on decreasing with due course of time. The above-mentioned methods of corrosion rate determination furnish an average value for a long-time interval. Looking at the versatility and minimum detection limit of the voltammetric method, the authors have developed a new voltammetric method for the determination of corrosion rate at short-time intervals. The results of corrosion of mild steel in 10% HC1 solution with and without NTMP inhibitor at short-time intervals have been reported. The corrosion inhibition efficiency of NTMP is 93% after 24£¿h. 1. Introduction Mild steel is a major material of construction. It is extensively used in chemical and allied industries for handling alkalis, acids, and salt solutions [1]. Hydrochloric (HC1) acid is the solvent most often employed for chemical cleaning. It attacks a wide range of scales [2]. Nitrogen compounds constitute the largest class of inhibitors for hydrochloric acid [3] solution. During the past decade a number of polymers and phosphonates have been used in different inhibitor compositions in aqueous and acid solutions [4]. They form stable complexes and some times act as detergent also. The role of inhibitor is the prevention of the adsorption of aggressive anions and reduction of the dissolution rate of the passivating oxide. In the present paper we have studied the action and effectiveness of nitrilo trimethylene phosphonic acid (NTMP) as inhibitor for corrosion of carbon steel in (10% HCl) acid solution. Most of the methods are proposed in the field of corrosion rate determination, but they furnish an average value for a long-time interval [5]. Looking at the sensitivity and minimum detection limits [6, 7] of polarographic techniques, that is, direct current polarography (DCP), differential pulse polarography (DPP), and voltammetric, that is, differential pulse anodic stripping voltammetric (DPASV) method has been used to determine the corrosion rates and inhibition efficiency of NTMP of mild steel in 10% HC1 solution at short time intervals. Significantly it has also been possible to determine the corrosion rates simultaneously with respect to Fe(II) and Fe(III) which is not
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