<p>This study investigates the high-temperature tribological performance of nano-CeO₂-modified multimodal Cr₃C₂-NiCr coatings (NMC) fabricated via high-velocity oxygen fuel (HVOF) spraying, in comparison with conventional Cr₃C₂-NiCr coatings (CC). Through comprehensive microstructural characterization, mechanical property evaluation, and high-temperature friction-wear tests (500-700&#xa0;°C, 20-50N), the synergistic effects of multimodal architecture and CeO₂ modification were elucidated. Results demonstrate that NMC exhibits a refined multimodal architecture comprising uniformly distributed nano-, submicron-, and micron-scale Cr₃C₂ particles embedded in a NiCr matrix, achieving significantly reduced porosity (0.30 ± 0.12% vs. 1.41 ± 0.15% for CC) and enhanced microhardness (1014.9 ± 72.2 HV₀.₃ vs. 906.4 ± 47.8 HV₀.₃). These improvements are attributed to synergistic mechanisms involving nano-CeO₂-induced solid-solution strengthening, grain refinement, and hierarchical carbide dispersion, which collectively optimize interfacial bonding, minimize structural defects, and enhance load-bearing capacity. At elevated temperatures, NMC achieves a lower friction coefficient (0.49-0.72 vs. 0.55-1.25 for CC) and reduced wear rates (1.88-3.3 × 10⁻⁵ mm³/N·m vs. 4.03-5.74 × 10⁻⁵ mm³/N·m for CC), owing to the formation of adherent Cr₂O₃-rich tribofilms and suppressed decarburization via CeO₂-mediated interfacial passivation. Wear surface and debris observations indicate that CC is dominated by adhesive wear, severe third-body abrasion, and lamellar delamination, whereas NMC shows mainly adhesive/abrasive wear with more persistent Cr₂O₃-rich tribofilms. The synergistic effect of the multimodal architecture and nano-CeO₂ modification improves NMC’s high-temperature tribological performance. These findings highlight the potential of nano-modified multimodal Cr₃C₂-NiCr coatings for high-temperature tribological applications, particularly in demanding industrial environments such as continuous casting crystallizers.</p>