In this study, carbide-metal composite coatings (WC-10Co4Cr) were prepared via high-velocity oxygen-fuel (HVOF) spraying, and the influence of Mo₂C addition on the microstructure, mechanical properties, and wear performance was systematically investigated. The results indicate that Mo₂C is solid-soluted in WC during the preparation process, which induces lattice distortion. Mo₂C addition results in refinement of the grain size of WC particles, homogenization of the binder phase distribution, and reduction of the porosity of the coatings. An appropriate amount of Mo₂C addition significantly enhances coating performance. The coating containing 2 wt.% Mo₂C exhibited optimal properties. It demonstrated the highest microhardness and the lowest porosity, and wear tests revealed it had the lowest friction coefficient and wear rate at room temperature, which is primarily due to enhanced hardness and density that effectively suppressed abrasive wear. At 400 °C, the coating with 2 wt.% Mo₂C addition also showed the most stable and lowest friction coefficient. The generated Mo-containing oxides acts as a solid lubricant, isolating friction surfaces and mitigating both oxidative and adhesive wear. However, excessive Mo₂C content leads to an abnormal increase in the volume fraction of the binder phase, accompanied by reduced hardness. This induces a transition of the wear mechanism toward adhesive wear dominance, with complex nonlinear evolution characteristics.

This study presents the fabrication of a Cr₃C₂-25NiCr/NiCr coating on Co₃W₃ steel utilizing high-velocity oxygen fuel (HVOF) spraying. The effects of the vacuum heat treatment process on the microstructures, mechanical properties, and wear mechanisms of the coating were systematically analyzed. The results indicated that the microstructure became denser following heat treatment. During the spraying procedure, decarburization resulted in transformation of the metastable phase structure into a stable one. In comparison to the sprayed coating, there was a 93.8% reduction in porosity. The precipitation of nano-secondary carbides shifted the mechanism of solid-solution strengthening to precipitation strengthening, resulting in a 29.1% increase in microhardness. Meanwhile, the thermal softening effect led to a 114.3% increase in fracture toughness. Wear experiments demonstrated that the friction-induced amorphous structure effectively mitigated stress concentration and inhibited crack initiation. The polycrystalline interface transition region between the nano-secondary carbides and the matrix facilitated the shedding of nano-secondary carbides, forming abrasive particles that generated a rolling effect, which significantly reduced the coefficient of friction. The semi-coherent interface between secondary carbides and NiCr decreased the interfacial energy and enhanced the bonding strength, effectively preventing the shedding of carbides during the wear process. Consequently, a dense microstructure, the type of interface, and high hardness and toughness were critical factors in enhancing its wear resistance.

To address the limitations of cobalt-based cermet in oxidative and high-temperature environments, this study investigates a (W,Ti)C-based cermet system incorporating a hybrid binder composed of nickel (Ni) and 304 stainless steel (304ss). A series of cermets with varying Ni/304ss binder metal ratios were fabricated via vacuum sintering at 1440 °C. The introduction of 304ss into the Ni matrix enhanced interfacial diffusion and phase stability, effectively suppressing core–rim structures and promoting a uniform microstructure. Notably, the cermet with 8%Ni–8%304ss composition achieved a Vickers hardness of 15.6 GPa and fracture toughness of 9.21 MPa·m^1/2, balancing mechanical strength and toughness. Isothermal oxidation testing at 450 °C showed that the hybrid binder substantially suppressed specific mass gain compared to monolithic Ni or 304ss systems. These improvements are attributed to the interplay between Ni-enhanced densification, which limits oxygen transport, and Cr-facilitated surface passivation, which stabilizes the oxide layer. The results highlight the potential of Ni-304ss hybrid binders as cobalt-free alternatives for high-performance tooling and wear-resistant applications in oxidative environments.

Conventional superhydrophobic coatings on aluminum alloys are frequently limited by inadequate coating-substrate adhesion, poor mechanical robustness, and the vulnerability of their surface micro/nanostructures to mechanical damage. To address these challenges, a hydroxyl-rich anodic oxide interlayer was formed via hard anodization followed by a subsequent hydroxylation treatment, thereby promoting interfacial bonding and providing abundant active anchoring sites for coating deposition. Based on this interface-engineering strategy, a mechanically durable superhydrophobic F-SiO₂@polyurethane (PU) composite coating with hierarchical micro/nanostructures was successfully fabricated on aluminum alloy substrates through a facile spray-coating process. The anodized substrate provides abundant hydroxyl groups and interface anchoring sites, while the PU matrix enhances structural integrity and facilitates particle fixation. By incorporating fluorinated SiO₂ nanoparticles, a hierarchical micro/nanostructure with low surface energy was fabricated. After 10,000 cm abrasion and 200 tape-peeling cycles, the coating maintained contact angles above 150°. The coating maintained superior corrosion resistance during prolonged immersion in acidic, alkaline, and saline environments. The improved durability and corrosion resistance originate from the synergistic effects of strong interfacial bonding, polymer barrier protection, and the fluorinated hierarchical structure. This study offers a promising strategy for developing durable superhydrophobic coatings for long-term protection of aluminum alloys.

Current antibacterial sprays face major limitations, including rapid evaporation, short-lived efficacy, skin irritation, and poor adhesion to surfaces, highlighting an urgent need for a durable and biocompatible alternative. To address these challenges, we developed a ZIF-8-based spray (ZNS-WO20) composed of ZIF-8 nanoparticles dispersed in 50% ethanol and 20% OTES. OTES acts as a dispersant and binder, enabling wash-resistant coatings on gauze and glass. ZIF-8 exhibits pH-responsive Zn²⁺ release, achieving nearly 100% killing of S. aureus, E. coli, and methicillin-resistant S. aureus (MRSA) at 160 μg/mL through intracellular reactive oxygen species (ROS) generation. The spray maintains >95% antibacterial efficacy against S. aureus after five washing cycles and seven days of outdoor exposure, and causes no dermal irritation in rats. This work fills the gap for a long-lasting, skin-friendly antibacterial spray, showing promise for healthcare disinfection and surface protection.

Conventional superhydrophobic coatings on aluminum alloys are frequently limited by inadequate coating–substrate adhesion, poor mechanical robustness, and the vulnerability of their surface micro/nanostructures to mechanical damage. To address these challenges, a hydroxyl-rich anodic oxide interlayer was formed via hard anodization followed by a hydroxylation treatment, thereby enhancing interfacial bonding and providing abundant active anchoring sites for coating deposition. Using this interface-engineering strategy, a mechanically durable superhydrophobic F-SiO₂@polyurethane (PU) composite coating with hierarchical micro/nanostructures was successfully fabricated on aluminum alloy substrates through a facile spray-coating process. The anodized substrate provides abundant hydroxyl groups and interfacial anchoring sites, while the PU matrix enhances structural integrity and facilitates particle fixation. Incorporating fluorinated SiO₂ nanoparticles produced a hierarchical micro/nanostructure with low surface energy. After 10,000 cm of abrasion and 200 tape-peeling cycles, the coating maintained contact angles above 150°. The coating maintained superior corrosion resistance during prolonged immersion in acidic, alkaline, and saline environments. The improved durability and corrosion resistance originate from the synergistic effects of strong interfacial bonding, polymer barrier protection, and the fluorinated hierarchical structure. This study offers a promising strategy for developing durable superhydrophobic coatings for long-term protection of aluminum alloys.