Addition of Niobium in Fe-13cr-4.5al-2mo Alloy Used as Atf Cladding: Effect on High Temperature Water Corrosion and In-Situ Electrochemistry

•Four Fe-13Cr-4.5Al-2Mo alloys with different Nb content were designed.•In-situ electrochemistry was conducted to quantitatively verify corrosion behavior in 360 °C lithiated and borated water.•Slight Nb addition benefits corrosion resistance due to larger oxide impedance and delayed oxidation of Fe2Nb particles.•Cathodic Tafel kinetics of in-situ polarization curves reveals the oxygen reduction mechanism on FeCrAl surface.