In this study, the ceramic coating was prepared on Ti6Al4V alloy by scanning micro-arc oxidation (SMAO). The growth features of SMAO coating were investigated by combining the voltage and discharge variation. The result shows that a higher working voltage is obtained during SMAO treatment owing to additional resistance from the electrolyte column. As the SMAO goes on, the discharge region moves to the electrolyte column edge, exhibiting an annular shape. The current density with Gaussian distribution is observed between the stainless-steel tube (cathode) and titanium substrate (anode), which causes the SMAO coating to show a higher thickness in the middle and lower on both sides. Similar to traditional MAO, the SMAO coating has an enhancement in the thickness, pore size and Si content with increasing oxidation time, but coating degradation occurs in the later stage of SMAO. The SMAO coating mainly consists of amorphous SiO₂, rutile and anatase phases.

The extremely harsh environment of the high temperature plasma imposes strict requirements on the construction materials of the first wall in a fusion reactor. In this work, a refractory alloy system, WTaVTiZr_x, with low activation and high entropy, was theoretically designed based on semi-empirical formula and produced using a laser cladding method. The effects of Zr proportions on the metallographic microstructure, phase composition, and alloy chemistry of a high-entropy alloy cladding layer were investigated using a metallographic microscope, XRD (X-ray diffraction), SEM (scanning electron microscope), and EDS (energy dispersive spectrometer), respectively. The high-entropy alloys have a single-phase BCC structure, and the cladding layers exhibit a typical dendritic microstructure feature. The evolution of microstructure and mechanical properties of the high-entropy alloys, with respect to annealing temperature, was studied to reveal the performance stability of the alloy at a high temperature. The microstructure of the annealed samples at 900 °C for 5–10 h did not show significant changes compared to the as-cast samples, and the microhardness increased to 988.52 HV, which was higher than that of the as-cast samples (725.08 HV). When annealed at 1100 °C for 5 h, the microstructure remained unchanged, and the microhardness increased. However, after annealing for 10 h, black substances appeared in the microstructure, and the microhardness decreased, but it was still higher than the matrix. When annealed at 1200 °C for 5–10 h, the microhardness did not increase significantly compared to the as-cast samples, and after annealing for 10 h, the microhardness was even lower than that of the as-cast samples. The phase of the high entropy alloy did not change significantly after high-temperature annealing, indicating good phase stability at high temperatures. After annealing for 10 h, the microhardness was lower than that of the as-cast samples. The phase of the high entropy alloy remained unchanged after high-temperature annealing, demonstrating good phase stability at high temperatures.

Control of exposed crystal facets in nanostructures is scientifically important, but technically challenging due to the inherent difficulty in manipulating surface energy of crystals. Here, laser‐induced periodic surface structures (LIPSS) induced by femtosecond laser is applied to produce periodic subwavelength 1D nanostructures with high index crystal facets on epitaxial CoFe₂O₄ surfaces, providing an efficient, maskless, cost‐effective “top‐down” method for nanostructure fabrication. Homogenous 1D LIPSSs (1D‐LIPSSs) with a period of 131 ± 15 nm and a depth of 90 ± 5 nm are obtained. The orientation of LIPSS nanostructures is finely controlled by tuning the polarization of fs laser beam, therefore flexibly producing 1D‐LIPSSs along various crystallographic orientations. Gas sensing performance evaluation shows that the fabrication of 1D‐LIPSSs on CoFe₂O₄ enlarges its surface area and contributes to enhanced gas sensing response. Compared to CoFe₂O₄ with LIPSSs faceted along {100} orientation, CoFe₂O₄ with LIPSSs faceted along high‐index {110} facets exhibits further improved gas sensing performance, suggesting the critical role of high‐index crystal facets in promoting surface reactivity and sensing sensitivity. The development of a laser‐based nanostructure fabrication route with high controllability of exposed crystal facets provides a novel solution for high‐density film‐based gas sensing applications.