It was found that Fe_(50)Mn_(30)Co_(10)Cr_(10) medium entropy alloy (MEA) had superior mechanical properties higher than those of CoCrFeMnNi high entropy alloys (HEA). However, poor corrosion due to the higher manganese content is one of the main challenges restricting the further application of Fe_(50)Mn_(30)Co_(10)Cr_(10) MEA. In order to improve the corrosion resistance of MEA, a new cerium chemical conversion coating based on a mixed solution of Ce(NO_3)_3. 6H_2O and H_2O_2 has been first proposed in this study. The electrochemical behavior of bare and coated samples was evaluated by using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). In addition, Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscope (TEM), Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS) were utilized to characterize the microstructure and composition of the coatings. The preliminary results showed that, from the potentiodynamic curves, the corrosion potential increases and the corrosion current density decreases by one order of magnitude for Ce-coated sample. Also, the cerium conversion process improves the pitting potential of the Fe_(50)Mn_(30)Co_(10)Cr_(10) MEA. The AES result revealed that the thickness of cerium conversion film formed on the surface of Fe_(50)Mn_(30)Co_(10)Cr_(10) MEA is around 25 nm.
展开▼
