The air-plasma-sprayed ceria and yttria-stabilized zirconia (CYSZ) coating was modified by selective laser remelting and Al deposition to enhance hot corrosion resistance. The dotted coating was obtained after selective laser remelting. Magnetron sputtering was used to deposit an Al film on the dotted coating, and a vacuum heat treatment was subsequently performed to produce a dense α-Al₂O₃ overlay. Hot corrosion behavior of the following three types of coatings was investigated: plasma-sprayed, dotted, and dotted coatings combined with Al deposition (DA). Hot corrosion behaviors were evaluated in a mixture of 55 wt % V₂O₅ and 45 wt % Na₂SO₄ molten salts at 1000 °C for 30 h. The hot corrosion reaction between molten salts and zirconia stabilizers (Y₂O₃ and CeO₂) led to the generation of monoclinic zirconia, YVO₄, and CeVO₄ plate-shaped crystals, and the mineralization of CeO₂. The results indicated that the hot corrosion resistance of the DA coating was the best, and the dotted coating had superior hot corrosion resistance in comparison with the plasma-sprayed coating. The minimal surface roughness and dense dotted units improved the hot corrosion resistance of the dotted coating. The dense α-Al₂O₃ overlay with chemical inertness effectively inhibited the infiltration of molten salts, which led to the optimal hot corrosion resistance of the DA coating.

Combining the advantages of a wet chemical method and spark plasma sintering, carbide-doped materials W-1wt%TiC and W-1wt%ZrC were prepared. Microstructural evolution in W-1wt%TiC and W-1wt%ZrC under irradiation of 5 keV He⁺ at 600 °C to fluences up to 5.0 × 10²¹ ions/m² with ion flux of about 8.8 × 10¹⁷ ions/m²s was investigated by transmission electron microscopy (TEM). The dislocation loop number density of W-1wt%TiC was higher than that of W-1wt%ZrC, but the average loop size of the W-1wt%TiC was in average smaller. There were no observable helium bubbles in W-1wt%TiC and W-1wt%ZrC, exhibiting higher radiation resistance to He⁺ compared to pure W. He⁺ pre-damaged and undamaged W-1wt%TiC and W-1wt%ZrC samples were irradiated by 5 keV D₂⁺ to estimate the D retention in doped W materials. The irradiation damage impact of He⁺ on deuterium retention was examined by a method of thermal desorption spectroscopy (TDS). Compared with the undamaged samples, it was illustrated that D₂ retention of W-1wt%TiC and W-1wt%ZrC increased after He⁺ pre-irradiation.

In recent years, yttrium oxide coatings prepared by atmospheric plasma spraying (APS) have been employed extensively in semiconductor processing equipment. Meanwhile, defects in yttrium oxide coating, such as unmelted particles and pores, reduce the etching resistance of the coating. In this work, two yttrium oxide coatings were prepared by in situ laser-assisted plasma spraying (LAPS) coupled with a 500 W and 600 W laser for comparison with a coating prepared by APS, and the effects of the laser on the coating properties were investigated. The results show that the surface roughness was reduced by 25.7% (500 W) and 25.3% (600 W) and the porosity was reduced by 52.3% (500 W) and 36.9% (600 W) after laser coupling. After being etched by CF₄/CHF₃ for a long time, it was observed from SEM, EDS and XPS analyses that the intensity ratios of the Y-F bonds in the coating were 1 (APS):1.3 (LAPS+500W):1.1 (LAPS+600W), which indicated that the LAPS+500W coating had a thicker fluorination layer. It was also observed that the fluorination layer at the defect was first eroded; then, the erosion area gradually spread to the surrounding area, and finally, the fluorination layer was etched. This indicated that the defects had a significant impact on the etching resistance. Consequently, the LAPS+500W coating with fewer defects and a thicker fluorination layer showed the lowest etching rate. Therefore, in situ laser-assisted plasma spraying coupled with an appropriate laser power is an effective method to improve the performance of yttrium oxide coatings.

To fulfill the harsh surface demand for key industrial components, metal matrix composite coatings (MMC) with hard ceramic particles located in the metallic matrix have attracted considerable attention in recent years. In this paper, WC/Stellite-6 composite coatings were fabricated via supersonic laser deposition (SLD). The effects of laser heating temperature, WC particle size and addition content on the deposition characteristics were systematically studied. The microstructures and mechanical properties of the as-prepared composite coatings were examined. The results demonstrated that increasing laser heating temperature can improve powder deposition efficiency for both coarse and fine WC-reinforced coatings. The peak coating height of fine WC-reinforced composite coating is 1157 μm, which is higher than that of coarse WC-reinforced composite coating (505.5 μm) deposited under the same laser heating temperature. The increase in laser heating temperature and WC addition content in original composite powder resulted in the increase in WC fraction in the composite coating, which can achieve a highest value of 55.9 vol.%. The SLD composite coating had comparable bonding strength (145.5 MPa) to that of laser cladded (LC) coating. The SLD specimen showed plastic fracture behavior, which was different from brittle fracture behavior for the LC sample.