Reactive ultrafast high-temperature sintering of (La0.2Gd0.2Sm0.2Eu0.2M0.2) 2Zr2O7 (M=Y or Yb) high-entropy ceramics
1
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
In the present work, a single-phase (La0.2Gd0.2Sm0.2Eu0.2Y0.2)2Zr2O7 (LGSEY) high-entropy ceramic with pyrochlore structureand a dual-phase (La0.2Gd0.2Sm0.2Eu0.2Yb0.2)2Zr2O7 (LGSEYb) high-entropy ceramic with co-existing pyrochlore and fluoritestructure were designed by cation radius differences and successfully synthesized by reactive ultrafast high-temperaturesintering (RUHS). The synthesis was completed in less than 1 h, demonstrating the efficiency of the RUHS technique forpreparing complex high-entropy Re2Zr2O7 ceramics. XRD results showed that RUHS could synthesize high-entropy Re2Zr2O7with a specified phase composition. TEM and SEM confirmed the uniform distribution of rare-earth elements in the ceramics,minimizing compositional bias and enhancing material properties. Both ceramics exhibited low thermal conductivity due tosignificant lattice distortion, with LGSEYb displaying an amorphous thermal conductivity. In addition, the inherent cationicradius differences and lattice distortions in high-entropy ceramics contribute to the low Young’s modulus and high hardness. Finally, both ceramics exhibit excellent high-temperature phase stability from room temperature to 1500 ℃. This workhighlights the potential of RUHS for synthesizing high-entropy ceramics with complex structures and provides valuableinsights for optimizing their use in thermal barrier coatings.
Abstract
In the present work, a single-phase (La0.2Gd0.2Sm0.2Eu0.2Y0.2)2Zr2O7 (LGSEY) high-entropy ceramic with pyrochlore structureand a dual-phase (La0.2Gd0.2Sm0.2Eu0.2Yb0.2)2Zr2O7 (LGSEYb) high-entropy ceramic with co-existing pyrochlore and fluoritestructure were designed by cation radius differences and successfully synthesized by reactive ultrafast high-temperaturesintering (RUHS). The synthesis was completed in less than 1 h, demonstrating the efficiency of the RUHS technique forpreparing complex high-entropy Re2Zr2O7 ceramics. XRD results showed that RUHS could synthesize high-entropy Re2Zr2O7with a specified phase composition. TEM and SEM confirmed the uniform distribution of rare-earth elements in the ceramics,minimizing compositional bias and enhancing material properties. Both ceramics exhibited low thermal conductivity due tosignificant lattice distortion, with LGSEYb displaying an amorphous thermal conductivity. In addition, the inherent cationicradius differences and lattice distortions in high-entropy ceramics contribute to the low Young’s modulus and high hardness. Finally, both ceramics exhibit excellent high-temperature phase stability from room temperature to 1500 ℃. This workhighlights the potential of RUHS for synthesizing high-entropy ceramics with complex structures and provides valuableinsights for optimizing their use in thermal barrier coatings.