The rock-salt structured (MgCoNiCuZn)O high-entropy oxide (HEO) ceramics exhibit great potential for high-temperature applications, yet its tribological behavior across a wide temperature range remains to be fully deciphered. This work systematically investigated the wide-temperature tribological mechanisms of (MgCoNiCuZn)O from room temperature (RT) to 800 ℃. The results indicate that the HEO's hardness and wear resistance displayed a non-monotonic dependence on temperature, while simultaneously demonstrating a reversible entropy-driven phase transition. At 400 ℃, thermodynamic instability triggered CuO precipitation, which disrupts the high-entropy structure and leads to a significant degradation in hardness and increased the wear rate. However, at the elevated temperature of 800 ℃, an entropy-driven re-dissolution of CuO partially restores the high-entropy structure, leading to a recovery in hardness. Concurrently, a continuous, lubricious oxide film formed on the worn surface. Density functional theory (DFT) calculations reveal that the low binding energy and high electron activity of CuO underpin its preferential precipitation and its key role in forming the Cu-rich oxide lubricating film. The synergy between phase re-stabilization and surface film formation results in excellent high-temperature wear resistance, with a minimum wear rate of approximately 0.53×10^-5 mm³·(N·m)^-1 at 800 ℃. This work elucidates the phase evolution and tribological mechanisms of HEO across a wide temperature range, providing valuable guidance for designing advanced wear-resistant materials for extreme environments.

Electromagnetic wave absorption (EWA) aerogels combine high porosity and large specific surface area, which reduce the effective dielectric constant and improve impedance matching, thereby enhancing EWA capability. However, most reported fabrication strategies rely on complex processes such as supercritical drying or freeze-drying, hindering large-scale production. Achieving both high EWA performance and scalable production remains challenging. Herein, we select carbon nanotubes (CNTs) as the dielectric loss phase, nickel ferrite (NiFe₂O₄) as the magnetic loss phase, and cellulose nanofibers (CNFs) as the skeleton to assemble a novelty CNT/NiFe₂O₄/CNF (CNC) aerogel through simple solvent exchange, ion crosslinking, and ambient pressure drying. Solvent exchange and Ca²⁺ coordination with carboxyl groups of CNFs and CNTs suppress capillary-induced structural collapse and maintain the porous network of the CNC aerogel during ambient drying. The introduction of CNTs enhances the conductive network and interfacial polarization, while maintaining favourable impedance matching. As the content of CNTs increases, the dielectric constant gradually rises, while the magnetic loss remained stable. The optimized CNC aerogel achieves the reflection loss of −55.62 dB at the frequency of 6.42 GHz with a matching thickness of 2.80 mm, and an effective absorption bandwidth that covers 10.65 GHz at a thickness of 1.53 mm. Radar cross-section simulations further confirmed its potential for practical EWA applications. The assembly strategy provides a scalable route to lightweight, broadband EWA aerogels.