The lifetime of Si bond coatings in environmental barrier coatings is constrained by phase-transition-induced cracking of the SiO_(2)scale.In this study,Si-HfO_(2)dual-state duplex composite materials are proposed to ...The lifetime of Si bond coatings in environmental barrier coatings is constrained by phase-transition-induced cracking of the SiO_(2)scale.In this study,Si-HfO_(2)dual-state duplex composite materials are proposed to address this issue by partially forming HfSiO_(4)and minimizing the SiO_(2)content.The as-prepared composite exhibited a structure comprising discrete HfO_(2)“bricks”embedded in a continuous Si“mortar”,while the oxidized state transformed into discrete HfSiO_(4)“bricks”within continuous thin SiO_(2)“mortars”.The results indicate that continuous thin SiO_(2)contributes to reducing the oxidation rate to a level comparable to that of pure Si,and discrete HfSiO_(4)particles aid in relieving phase transition-induced stress and inhibiting crack propagation,thereby enhancing oxidation and cracking resistance simultaneously.Consequently,the composite with 20 mol%HfO_(2)and a mean particle size of~500 nm at 1370℃exhibited a service lifetime 10 times greater than that of pure Si.This research provides valuable insights for designing Si-based bond coatings with improved service lifetime.展开更多
基金This study is supported by the Postdoctoral Innovative Talent Support Program(No.BX2021238)the National Natural Science Foundation of China(No.U22A20110)the Natural Science Foundation of Suzhou(No.SYG202103).
文摘The lifetime of Si bond coatings in environmental barrier coatings is constrained by phase-transition-induced cracking of the SiO_(2)scale.In this study,Si-HfO_(2)dual-state duplex composite materials are proposed to address this issue by partially forming HfSiO_(4)and minimizing the SiO_(2)content.The as-prepared composite exhibited a structure comprising discrete HfO_(2)“bricks”embedded in a continuous Si“mortar”,while the oxidized state transformed into discrete HfSiO_(4)“bricks”within continuous thin SiO_(2)“mortars”.The results indicate that continuous thin SiO_(2)contributes to reducing the oxidation rate to a level comparable to that of pure Si,and discrete HfSiO_(4)particles aid in relieving phase transition-induced stress and inhibiting crack propagation,thereby enhancing oxidation and cracking resistance simultaneously.Consequently,the composite with 20 mol%HfO_(2)and a mean particle size of~500 nm at 1370℃exhibited a service lifetime 10 times greater than that of pure Si.This research provides valuable insights for designing Si-based bond coatings with improved service lifetime.
