Gradient tri-layered TGOs in MoSi 2/HfO 2 duplex EBCs for effective protection of SiC substrate against steam corrosion at 1500 °C for 200 h

作者：Kexue Peng, Ying Qiao, Qian Li, Xinxin Cao, Long Wang, Guifang Han, Jianzhang Li, Jingyu Qin, Jingde Zhang · 发表于：Journal of Advanced Ceramics · 年份：2025 · DOI：10.26599/jac.2025.9221101 · 被引用次数：10 · 研究领域：Semiconductor materials and devices、MXene and MAX Phase Materials、Advanced ceramic materials synthesis

The protective effectiveness of environmental barrier coatings (EBCs) for SiC-based composites is challenged by the thickening and phase transformation of the SiO 2 scale, known as thermally grown oxide (TGO). In this study, a tri-layered TGOs scale, comprising cristobalite, Hf-doped SiO 2 glass, and particle-reinforced Hf-Si-O glass, was formed during the oxidation of MoSi 2 /HfO 2 duplex EBCs. The incorporation of the gradient Hf-doping and HfO 2 /HfSiO 4 particle-reinforcement were demonstrated to effectively suppress the crystallization and phase transition of the SiO 2 and mitigate internal stress within the EBCs, generating a crack-blocking effect. This effect prevented the TGOs scale from further channel crack propagation, enabled the SiC substrate with no detectable corrosion after 200 hours of exposure at 1500 °C in steam, even when the TGOs thickness reached 24.5 μm. This work presents a novel strategy to simultaneously extend the service lifetime and enhance the high-temperature capability of EBCs through the tailored design of TGOs composition and structure.