The influence of water vapour on high-temperature oxidation of Al,Co,Cr,Ni-containing high entropy alloys under thermal shock conditions

Abstract

The goal of this work is to determine the influence of water vapour on the corrosion properties of Al25Co25Cr25Ni25, Al20Co25Cr25Ni25Si5, Al20Co5Cr20Fe20Ni35 and Al10Co15Cr20Fe20Ni35 high entropy alloys under thermal shock conditions in synthetic air, air-10 %H2O and air-50 %H2O at 1000 °C. The oxidation kinetics suggest that H2O addition results in more significant scale spallation. Only Al25Co25Cr25Ni25 was capable of relatively insignificant mass loss, even at 50 %H2O, due to its capability of forming a more continuous Al2O3 layer. It can be concluded that 25 at% Al is required to ensure the appropriate protection in cyclic conditions against water vapour-containing corrosive environments at high temperatures.