Morphological and Electrochemical Investigation of Aluminum Nano-Coating on Mild Steel Using Vacuum Evaporator System

This study investigates the morphological and electrochemical properties of aluminum (Al) nano-coatings deposited on mild steel substrates using a vacuum thermal evaporation technique. The primary aim was to enhance the corrosion resistance of mild steel through controlled deposition of Al films with varying thicknesses (4 nm, 6 nm, 8 nm, 10 nm, and 60 nm). Morphological characterization was performed using Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). While electrochemical behavior was assessed through Linear Polarization Resistance (LPR), Tafel analysis, and Electrochemical Impedance Spectroscopy (EIS) in a 0.5 M NaCl solution. Results revealed that surface morphology and roughness improved significantly with increasing Al thickness, with the 60 nm sample showing the most uniform and continuous coating. Electrochemical tests demonstrated enhanced corrosion resistance indicated by increased impedance values and reduced corrosion current densities at greater film thicknesses. The 60 nm coating exhibited optimal performance were reduced the corrosion rate by nearly 20% compared to the uncoated sample. X-ray Diffraction (XRD) confirmed successful Al deposition with distinct crystalline peaks observed in thicker films. The findings suggest that vacuum evaporated Al nano-coatings are highly effective in improving the surface integrity and corrosion resistance of mild steel, making them suitable for applications in harsh environments.