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

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 degrees 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.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

The purpose of this study is to investigate the effect of water vapor on the corrosion properties of different high entropy alloys under thermal shock conditions at 1000 degrees C. The results show that the addition of H2O leads to more significant scale spallation. Only the Al25Co25Cr25Ni25 alloy exhibits relatively insignificant mass loss even in the presence of 50 %H2O due to the formation of a more continuous Al2O3 layer. It can be concluded that a minimum of 25 at% Al is necessary to provide sufficient protection against water vapor corrosion at high temperatures in cyclic conditions.