A Ti3SiC2-LaB6 co-modified ceramizable composite with excellent high-temperature corrosion resistance

Carbon fiber/phenolic resin (CF/Ph) composite typically suffers from poor high-temperature corrosion resistance, limiting their reliability as thermal protection materials (TPMs) for solid rocket motor (SRM). Accordingly, a Ti 3 SiC 2 -LaB 6 synergistically co-modified carbon fiber/boron phenolic resin composite (CF/BPR) was developed. Its oxidation resistance, ablation behavior and ceramization mechanism were explored. The optimal sample Ti 50 La 15 (Ti 3 SiC 2 :LaB 6 mass ratio of 50:15), exhibited a high residual carbon yield of 43.8% at 1500 °C. When tested under an oxyacetylene flame at 4.3 MW/m 2 (∼3000 °C) for 20 s, it showed a linear ablation rate (LAR) of -0.0178 mm/s, a mass ablation rate (MAR) of 0.0258 g/s, and a low backside temperature of 159.3 °C. Microstructural and phase analyses reveal that Ti 3 SiC 2 and LaB 6 preferentially oxidize to consume oxygen and suppress carbon oxidation, while the resulting oxidation products promote crack filling and structural densification during ablation. The in-situ formation of a dense B–C–O–Si–Ti–La multiphase ceramic layer effectively enhances resistance to thermochemical erosion and heat penetration. This study demonstrates that the synergistic integration of MAX-phase and high-temperature ceramics as a novel and effective strategy for designing next-generation ceramizable TPMs.