Protection of 316L Stainless Steel by Mn0.5Mg0.5Fe2O4/Chitosan in HCl andH2SO4 Media

The use of corrosion inhibitors is one of the most economical and simplest method forovercoming the corrosion problems [1-3]. From the standpoint of safety, the expansion of nontoxicand effective inhibitors is required. Chitosan is a natural polycationic copolymer and isone of the important biopolymers that extensively used in pharmaceutical applications, such asin tissue engineering materials, drug carriers [4]. Chitosan is rich in hydroxyl and aminogroups, so it is a good potential inhibitor. Umoren et al. were estimated the inhibition action ofchitosan on the corrosion of mild steel in 0.1 M HCl solution. They found that chitosan inhibitcorrosion of mild steel even at a very low concentration and inhibition efficiency increases witha rise in temperature up to 96 %at 60°C and then drops to 93 % at 70 °C, while it slightlyincreases with an increase in chitosan concentration [5]. The inhibition action of 2-N,Ndiethylbenzeneammonium chloride N-oxoethyl chitosan and 12-ammonium chloride Noxododecanchitosan on the corrosion of carbon steel in 1 M HCl has been evaluated. Theresults illustrate that the inhibition efficiency of 2-N,N-diethylbenzene ammonium chloride Noxoethylchitosan in 1 M HCl at varying temperature is higher than for chitosan and 12-ammonium chloride N-oxododecan chitosan [1]. The main aim of this study is investigation ofinhibition action of Mg0.5Mn0.5Fe2O4/chitosan nanocomposite on the corrosion of 316L stainlesssteel in 2 M HCl and 1 M H2SO4 solutions. The synthesized nanocomposite was evaluatedusing X-ray diffraction (XRD) and field emission scanning electron micrographs (FESEM).The corrosion behavior of 316L stainless steel was estimated by using electrochemical methodsincluding potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)methods in both acidic media in the absence and presence of various concentration of chitosan,Mg0.5Mn0.5Fe2O4 and Mg0.5Mn0.5Fe2O4/chitosan nanocomposite. In order to designed the effectof temperature on the behavior of nanocomposite, polarization measurements in the temperaturerange of 25-65 °C was carried out for different concentration of three mentioned inhibitor.26 Comparing the results indicated that, for both acidic media, the inhibition efficiency ofMg0.5Mn0.5Fe2O4/chitosan nanocomposite at all investigated temperature is higher than chitosanand Mg0.5Mn0.5Fe2O4. The nanocomposite was found to inhibit corrosion even at a very lowconcentration (0.1 g/L) and high temperature (99 % at 65°C). Because of these features andnon-toxic properties of nanocomposite, we think this inhibitor can be introduced for use in theoil and gas industry.

Keywords:

Corrosion , Chitosan , Spinel , Potentiodynamic polarization , electrochemicalimpedance spectroscopy (EIS)