Protective Performance of Atomic Layer Deposition Al₂O₃ Ultra-thin Film on 37CrMnMo Steel Surface

Al₂O₃ ultra-thin films were deposited on 37CrMnMo steel surface by atomic layer deposition (ALD) technique. The compactness of films and protective effect of film thickness on the substrate were analyzed through polarization curves, electrochemical impedance spectroscopy and morphology characterization. The results show that the ultra-thin Al₂O₃ films were dense and uniform, and the porosity of films decreased with the increase of thickness. The corrosion current density of 37CrMnMo steel with 150 nm Al₂O₃ film deposited on the surface was reduced by three orders of magnitude compared with alloy steel base material. The Al₂O₃ films had a good protective effect on the corrosion of 37CrMnMo steel substrate in 0.1 mol/L NaCl solution.