Synergistic Al3 +/Y3+ stabilization of SiO2 glass network enabling SiCf/SiC composites with enhanced durability against high-temperature corrosion

Despite the excellent mechanical properties of SiC f /SiC composites, the extremely harsh corrosion limits their durability as structural materials for high-temperature applications. Here, we propose a synergistic Al 3+ /Y 3+ stabilization strategy to achieve highly durable SiC f /SiC composites with enhanced mechanical stability. This is realized by constructing an Al/Y co-diffused SiC matrix, which can form a robust YAlSi x O y glass network under high-temperature atmospheric (40% H 2 O & 60% O 2 ) corrosion. The Al/Y co-diffused SiC f /SiC composites (SiC f /SiC-Al40Y) exhibit high bending strength retention of 98.5% after corrosion at 1200 ℃, as well as 78.9% up to 1300 ℃, significantly exceeding those of the counterparts without diffusion treatment. The improved mechanical stability is primarily attributed to the synergistic Al 3+ /Y 3+ stabilization of corrosion-induced SiO 2 glass network, which can suppress the matrix cracking and thus mitigate the corrosion. This work demonstrates the strategy of synergistic Al 3+ /Y 3+ stabilization for constructing SiC f /SiC composites with enhanced durability, offering an innovative concept to develop SiC f /SiC composites applicable at higher temperatures for thermo-structural applications.