The positive impact of the reactive sputtered nanostructured Nb2O5 coatings to reduce the FCG rates of the 2524-T3 alloy in an aggressive medium

This work investigates the fatigue crack growth (FCG) behaviour of the 2524-T3 aluminium alloy uncoated and coated with reactive sputtered nanostructured Nb2O5 thin films. Fatigue and Fatigue-corrosion tests were carried out in air and an aggressive medium at a stress ratio R = (Kmin/Kmax) of 0.1, employing frequencies of 10 Hz (air) and 0.1 Hz (0.6 mol L-1 NaCl solution), using a sinusoidal waveform. The Nb2O5 coatings were found to positively modify the FCG resistance of the 2524-T3 alloy for the same value of stress intensity factor (ΔK), acting as a protective barrier against localised corrosion process, and reducing FCG rates in aggressive environment. • Fatigue-corrosion tests were performed in sodium chloride solution. • Middle-Tension M(T) specimens were functionalized by using reactive sputtering technique. • The reactive sputtering technique was able to produce Nb2O5 coatings on the 2524-T3 Al alloy. • Nb2O5 coatings decreased the fatigue crack growth rates by 25