Al/Al₂O₃ coating with a total thickness of approximately 3 μm was irradiated by 6 MeV Au-ions with the damage level from 13 to 39 dpa at room temperature. The results showed that the surface roughness of the Al/Al₂O₃ coating decreased with increasing irradiation damage levels. As the irradiation damage level is up to 39 dpa, the crystallinity of the Al₂O₃ layer is enhanced, and the irradiation-induced defects such as voids and dislocations appeared in the Al/Al₂O₃ coating. The decreased hardness and the deterioration of deuterium permeation resistance are strongly associated with the changed microstructure. The underlying mechanism for the evolution of the microstructure and properties induced by Au-ion irradiation is discussed.

AlCrTaTiZr, AlCrTaTiZr nitride, and AlCrTaTiZr oxide coatings as tritium permeation barriers (TPBs) were prepared by magnetron co-sputtering technology on a CLF-1 (RAFM) substrate, to evaluate their hydrogen/deuterium permeation resistance. X-ray diffraction (XRD) analysis showed that the as-deposited coatings were amorphous. Scanning electron microscopy (SEM) results revealed that the deposition rates of the AlCrTaTiZr coating, AlCrTaTiZr nitride coating and AlCrTaTiZr oxide coating were approximately 2 μm h⁻¹, 0.75 μm h⁻¹ and 0.15 μm h⁻¹, respectively. The properties of these high-entropy alloy (HEA) coatings were studied with electrochemical hydrogen (ECH) permeation test equipment and a high-temperature gas-driven deuterium permeation (GDP) device. The AlCrTaTiZr HEA coating had the best hydrogen permeation resistance during the electrochemical hydrogen permeation test. However, the AlCrTaTiZr nitride coating had the best deuterium permeation resistance during the gas-deuterium permeation test. Annealing experiments of these coatings showed that changes in their microstructures during the gas-driven deuterium permeation test were the main reasons for the different permeabilities of these coatings during the heating and cooling processes. The oxidization of the HEA coating during the deuterium permeation experiment may have been the main reason that the HEA coating showed better deuterium permeation resistance than the HEA oxide coating.

FeCrAlY coatings deposited on the outer surface of the cladding tube by the magnetron sputtering with varying bias voltages (0 V to −500 V) were corroded at 550°C to 600°C in oxygen-saturated and oxygen-poor lead-bismuth eutectic for 500 h to 1,000 h. The increased bias voltage led to the Al content decreased and the Y content increased. The coating changed from columnar crystals to equiaxed crystals with increased bias voltage. The decreased bias voltage makes an improved corrosion resistance. The fundamental process governing the evolution of microstructure and corrosion resistance in the FeCrAlY coatings was discussed.