Plasma sprayed AlCoCrFeNi and MnCoCrFeNi high entropy alloys: high temperature stability, coating elastic properties and surface roughness

High Entropy Alloys (HEAs) are a new class of alloys with multi-principle elements mixed in equi-atomic ratio resulting in simple solid solutions. HEAs are known for their high temperature microstructural stability, and enhanced oxidation and wear resistance. Apart from bulk material processing routes such as casting and sintering, HEAs can also be deposited as a surface coating. In the present study, thermal sprayed HEA coatings are investigated as an alternative bond coat material for a thermal barrier coating system. Nanostructured HEA powders of AlCoCrFeNi and MnCoCrFeNi were prepared by ball milling and then plasma sprayed. Subsequently, the high temperature stability of the HEA powders as well as the as-sprayed coating mechanical properties and coating surface roughness of both type of HEAs coatings were characterized.