Evaluation corrosion behavior on commercial stainless steel SS 304 in Nano fluids water-Al2O3 system at different pH by Electrochemical Impedance Spectroscopy methods

Abstract

The corrosion behavior on commercial stainless steel SS 304 in Nano fluids water-Al2O3 system at pH 3 until 7 conditions has been investigated using electrochemical methods. The electrochemical tests were performed with and without the addition chlor to adjust of pH Nano fluid condition. The pH of nano fluid for testing corrosion stainless steel 304 are 3.18,.3.65, and 5. 9. The electrochemical technique used in this study, were open circuit potential (OCP), galvanodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of open circuit potential tests showed that the corrosion potential (Ecorr) values of stainless steel 304 in nanofluid at three pH values are slightly different between pH neutral and acidic. At pH 5.9 corrosion potential more positive compare with at acid pH 3.18. The positive potential of corrosion potential at pH 5.9 due to development of chromium oxide (Cr2O3) film formed on stainless steel is more stable in 5.9 than in acidic with the presence of Cl. However, galvanodynamic polarization of stainless steel SS 304 in nanofluid showed that the lowest corrosion of stainless steel SS 304 in nanofluid at pH 5.9 than stainless steel at condition in acidic pH 3.18 and 3.65. EIS study shows that stainless steel SS 304 in nanofluid showed the higher impedance at higher pH than at in acidic condition at lower pH. The higher impedance indicated that the passive film of Cr2O3 formed on the surface of stainless steel and reduce corrosion rate. In terms of corrosion rate values, stainless steel alloy showed the best corrosion rate in low pH nanofluid compared with high pH value. This shows that the interaction between Nano fluids and the stainless steel have no significant effect onto its corrosion behavior.