This paper presents a study of the structural and mechanical degradation of tungsten under steady-state mixed hydrogen–helium plasma (He/H₂). The experiments were carried out on the KAZ-PSI linear plasma simulator at a surface temperature of 1100 °C, while the helium fraction in the mixture was varied from 5% to 50%. Changes in surface morphology, roughness, phase composition, micromechanical response, and gas retention were analyzed using profilometry, scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), nanoindentation, and thermal desorption spectroscopy (TDS). The results show that increasing the helium fraction promotes the formation of a porous, defect-rich near-surface layer and modifies the gas-trapping behavior of tungsten. The surface roughness increases moderately from 0.031 μm for the initial polished state to 0.065 μm after exposure to a 50% He/50% H₂ plasma. EDS and XRD confirm that the observed degradation is not associated with detectable oxidation, carburization, or the formation of secondary crystalline phases. The TDS results indicate that helium-related vacancy complexes and gas-filled pores act as deep trapping sites for hydrogen. Therefore, the helium-modified near-surface layer should be considered as a trapping barrier that localizes hydrogen in the radiation-damaged layer rather than as a quantitatively proven diffusion barrier blocking hydrogen penetration into the bulk.

In the present work, the influence of technological parameters of detonation sputtering, in particular the degree of barrel filling, on the properties of chromium oxide (Cr₂O₃) coatings was investigated. Coatings were obtained under different sputtering conditions and analyzed comprehensively using X-ray phase analysis, optical and electron microscopy, and measurements of microhardness, porosity, and tribological characteristics. The results showed that the degree of barrel filling significantly affects the microstructure, thickness, porosity, and mechanical properties of the coatings. The sample obtained at 58% barrel filling showed the lowest porosity (0.01%), uniform distribution of chromium oxide, and the best adhesion, which makes it possible to consider this mode as optimal for the formation of wear-resistant coatings by detonation spraying.

This paper investigates the influence of sputtering parameters on the properties of tantalum-based detonation coatings. One of the key parameters in sputtering is the volume of barrel filling, which affects the properties of the resulting coatings. Tantalum coatings were produced at various levels of barrel filling with explosive gas, specifically at 50–70% fill levels. The results demonstrated that the roughness of the coatings decreases as the barrel fill volume increases, leading to coatings with a more homogeneous structure. Additionally, the tests revealed that coatings produced at 60% fill exhibited superior corrosion resistance compared to the other samples. Based on these findings, the optimal barrel fill level for explosive gas was determined.

This study investigates the effect of high-temperature hydrogen exposure on the structure and properties of Cr₂O₃/Al₂O₃-based detonation coatings deposited on AISI 316L stainless steel. Bilayer and gradient coatings were exposed to hydrogen at 1000 °C for 3, 4, and 5 h and subsequently characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), surface profilometry, and thermal desorption spectroscopy (TDS). One independent specimen was examined for each combination of coating architecture and hydrogen exposure duration. Therefore, the present study was designed as an exploratory comparative investigation rather than a statistically powered study. The principal α-Al₂O₃ and Cr₂O₃ phases remained detectable after all exposure durations, indicating preservation of the main oxide phases. SEM/EDS analysis revealed microcracks, local defects, and heterogeneous surface regions, with more pronounced localized damage in the bilayer coatings. The Ra values of the bilayer coatings were 1.385, 0.833, and 1.207 μm after 3, 4, and 5 h, respectively, whereas the corresponding values for the gradient coatings were 1.049, 1.337, and 1.049 μm. The minimum Ra of 0.833 μm after 4 h in the bilayer coating coincided with SEM/EDS evidence suggesting local coating damage and possible thinning. TDS showed the most intense hydrogen desorption for the gradient coating after 3 h. Overall, the observed results suggest that coating architecture influences surface evolution and hydrogen-retention behavior under the investigated high-temperature hydrogen exposure conditions.

Tungsten plasma-facing components in fusion devices may experience sequential exposure to helium and hydrogen, making irradiation history an important factor in their subsequent structural and hydrogen-release behavior. This study investigated polycrystalline tungsten exposed to He-only, H₂-only, and sequential He → H₂ plasmas at 700, 900, 1100, and 1300 °C. Surface and cross-sectional scanning electron microscopy, X-ray diffraction, instrumented indentation, and thermal desorption spectroscopy (TDS) were used to characterize the resulting changes. SEM observations showed that the largest differences among the H₂-only, He-only, and sequential He → H₂ exposure conditions occurred at 1100 °C, whereas predominantly grain-scale surface morphology was observed for all three conditions at 1300 °C. The bcc-W structure was retained under all investigated conditions, with no detectable secondary crystalline phases. The apparent coherent diffraction domain size, estimated from the W(110) reflection using the Scherrer equation, increased monotonically with irradiation temperature, from approximately 48–55 nm at 700 °C to approximately 126 nm at 1300 °C. At 1100 °C, the H₂-only specimen exhibited a larger apparent coherent diffraction domain size than the He-containing specimens. The nanomechanical response also depended on temperature and exposure history. TDS revealed distinct high-temperature hydrogen-desorption behavior for the sequential He → H₂ specimens, particularly at 1100 and 1300 °C. Overall, the results indicate that the tungsten response under the present sequential protocol depends on both temperature and exposure history, and that structural convergence at elevated temperature does not necessarily correspond to equivalent hydrogen-release behavior.