Cerium oxide based coatings from similar to 100 to similar to 1400 nm in thickness were deposited onto Al 2024-T3 alloy substrates by magnetron sputtering of a 99.99% pure CeO2 target. The crystallite size of CeO2 coatings increased from 15 nm to 46 nm as the coating thickness increased from similar to 100 nm to similar to 1400nm. The inhomogeneous lattice strain increased from 0.36% to 0.91% for the 100 nm to 900 nm thick coatings and slightly decreased to 0.89% for the similar to 1400nm thick coating. The highest adhesion strength to Al alloy substrates was for the similar to 210 nm thick coating, due to a continuous film coverage and low internal stress. Electrochemical measurements indicated that sputter deposited crystalline CeO2 coatings acted as physical-barriers that provide good cathodic inhibition for Al alloys in saline solution. The similar to 900 nm thick CeO2 coated sample had the best corrosion performance that increased the corrosion resistance by two orders magnitude and lowered the cathodic current density 30 times compared to bare Al 2024-T3 substrates. The reduced defects and exposed surface, along with suppressed charge mobility, likely accounts for the improved corrosion performance as coating thickness increased from similar to 100 nm to similar to 900 nm. The corrosion performance decreased for similar to 1400nm thick coatings due in part to an increase in coating defects and porosity along with a decrease in adhesion strength. (C) 2015 Elsevier B.V. All rights reserved.