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

The use of corrosion inhibitors is one of the most economical and simplest method for overcoming the corrosion problems [1-3]. From the standpoint of safety, the expansion of non-toxic and effective inhibitors is required. Chitosan is a natural polycationic copolymer and is one of the important biopolymers that extensively used in pharmaceutical applications, such as in tissue engineering materials, drug carriers [4]. Chitosan is rich in hydroxyl and amino groups, so it is a good potential inhibitor. Umoren et al. were estimated the inhibition action of chitosan on the corrosion of mild steel in 0.1 M HCl solution. They found that chitosan inhibit corrosion of mild steel even at a very low concentration and inhibition efficiency increases with a rise in temperatureup to 96 %at 60°C and then drops to 93 % at 70 °C, while it slightly increases with an increase in chitosan concentration [5]. The inhibition action of 2-N,N-diethylbenzene ammonium chloride Noxoethyl chitosan and 12-ammonium chloride N-oxododecan chitosan on the corrosion of carbonsteel in 1 M HCl has been evaluated. The results illustrate that the inhibition efficiency of 2-N,Ndiethylbenzene ammonium chloride N-oxoethyl chitosan 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 of inhibition action of Mg0.5Mn0.5Fe2O4/chitosan nanocomposite on thecorrosion of 316L stainless steel in 2 M HCl and 1 M H2SO4 solutions. The synthesized nanocomposite was evaluated using X-ray diffraction (XRD) and field emission scanning electron micrographs (FESEM). The corrosion behavior of 316L stainless steel was estimated by using electrochemical methods including potentiodynamic polarization and electrochemical impedancespectroscopy (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 effect of temperature on the behavior of nanocomposite, polarization measurements in the temperature range of 25-65 °C was carried out for different concentration of three mentioned inhibitor. Comparing the results indicated that, for both acidic media, the inhibition efficiency of 0.5Mn0.5Fe2O4/chitosan nanocomposite at all investigated temperature is higher than chitosan and Mg0.5Mn0.5Fe2O4. The nanocomposite was found to inhibit corrosion even at a very low concentration (0.1 g/L) and high temperature (99 % at 65°C). Because of these features and nontoxicproperties of nanocomposite, we think this inhibitor can be introduced for use in the oil and gas industry.

Keywords:

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