CORROSION PROTECTIVE BEHAVIOR OF MoO3 AND Y2O3 COATED AZ31 ALLOY

Abstract

Herein, we have reported formulation of MoO3 and Y2O3 coatings over AZ31 alloy using organic binder. The coatings were characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy and Field Emission Scanning Electron Microscope (FESEM). The results indicate that the powders exhibit high crystalline nature. The electrochemical polarization studies were conducted using three electrode systems in 3.5% NaCl electrolyte. The corrosion resistance was examined using electrochemical impedance spectroscopy technique. The uncoated AZ31 alloy exhibited the corrosion potential (Ecorr) of -1.7 V (SCE) and corrosion current density of 3.4 x 10-4 mA/cm2. Similarly, the MoO3 coated AZ31 alloy showed the corrosion potential (Ecorr) of -1.5 V (SCE) and corrosion current density of 3.73 x 10-10 mA/cm2. Further, the Y2O3 coated AZ31 alloy showed the Ecorr of -1.3 V (SCE) and corrosion current density of 1.28 x 10-10 mA/cm2. Similarly, the impedance analysis also provides strong evidence that the Y2O3 coated AZ31 alloy exhibited higher corrosion resistance among all the samples. From the results, it is evident that the Y2O3 coated AZ31 alloy showed enhanced corrosion protection properties.