The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,...The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,a tri-layered TGO 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 gradient Hf doping and HfO_(2)/HfSiO_(4)particle reinforcement effectively suppressed the crystallization and phase transition of SiO_(2)and mitigated the internal stress within the EBCs,generating a crack-blocking effect.This effect prevented the scale of the TGOs from further channel crack propagation,enabling the SiC substrate with no detectable corrosion after 200 h of exposure at 1500℃in steam,even when the TGOs thickness reached 24.5μm.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 TGO composition and structure.展开更多
基金supported by the Creative Research Foundation of the Science and Technology on Thermostructural Composite Materials Laboratory(No.2023-JCJQ-LB-071-01-01).
文摘The protective effectiveness of environmental barrier coatings(EBCs)for SiC-based composites is limited by the thickening and phase transformation of the SiO_(2)scale,known as thermally grown oxide(TGO).In this study,a tri-layered TGO 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 gradient Hf doping and HfO_(2)/HfSiO_(4)particle reinforcement effectively suppressed the crystallization and phase transition of SiO_(2)and mitigated the internal stress within the EBCs,generating a crack-blocking effect.This effect prevented the scale of the TGOs from further channel crack propagation,enabling the SiC substrate with no detectable corrosion after 200 h of exposure at 1500℃in steam,even when the TGOs thickness reached 24.5μm.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 TGO composition and structure.
