High entropy (LaCeSmEuNd)₂Zr₂O₇ ceramic aerogel with low thermal conductivity and excellent structural heat resistance

Dimensions and thermal insulation properties of nanoporous ceramics are unstable at high temperatures due to structural disruptions. This work prepared high entropy (LaCeSmEuNd)₂Zr₂O₇ ceramic aerogel via non-alkoxide sol-gel, supercritical drying, and calcination. XRD and EDS analysis showed that the (LaCeSmEuNd)₂Zr₂O₇ ceramic existed as a single phase. SEM images demonstrated the successful synthesis of aerogel structure. After two hours of annealing at 1200 °C, the cylindrical sample pressed from (LaCeSmEuNd)₂Zr₂O₇ ceramic aerogel had a compressive strength of 58.75 MPa, and its diameter shrinkage was 0.56%, whereas the La₂Zr₂O₇ reached 13.68%. The thermal diffusivity of annealed (LaCeSmEuNd)₂Zr₂O₇ was as low as 0.119 mm² s⁻¹, and its thermal conductivity at room temperature was 0.073 W·m⁻¹ K⁻¹, which was attributed to lattice disorder, stable porous structure, and abundance of grain boundaries caused by high entropy effects. Extending the high entropy effect to ceramic nano-insulation products is beneficial for enhancing their thermal stability.