Erbium oxide as a new promising tritium permeation barrier

As a new hydrogen isotope barrier material, erbium oxide Er2O3, or erbia, has been tested. Investigations included both thermal load test and permeation measurements to determine whether erbia is compatible with other materials at elevated temperatures and if it suppresses hydrogen transport. It is found that a 1 μm thick crystalline erbia coating on a fusion relevant material, EUROFER 97, reduces permeability by a factor up to almost 103, while revealing good thermo-mechanical stability being deposited on different substrates. Since the coating is comparable with crystalline α-alumina in terms of hydrogen isotope permeation reduction, but possesses some advantages over alumina and is easier to produce, erbia is proposed as a material for a permeation barrier coating.