Research Progress on Lanthanum Zirconate Porous Materials for Thermal Insulation

Lanthanum zirconate porous material is a kind of high porosity materials with nanoparticles or microparticles as the basic building unit. These materials exhibit exceptionally low thermal conductivity and maintain remarkable phase stability up to their melting point, making them particularly promising for thermal insulation applications in the aerospace industry. However, sintering problems of lanthanum zirconate porous materials cause collapse and shrinkage of pore structure, resulting in relatively poor thermal resistance and thermal insulation. Researchers have employed precise control over pore sizes and particle dimensions to optimize the mesostructure, leading to a significant reduction in thermal conductivity. Specifically, template-based methods enable precise control over pore sizes at the micro-nano scale, while Sol-Gel techniques combined with varied drying processes facilitate regulation of particle dimensions at the nanoscale. Concurrently, introduction of single- or multi-element doping has proven effective in inducing controlled lattice distortion, which subsequently weakens thermodynamic diffusion processes and suppresses high-temperature grain growth. This dual strategy of morphological control and compositional engineering has substantially improved both thermal insulation capability and temperature resistance of lanthanum zirconate porous materials. This review begins by introducing crystal structure of lanthanum zirconate, highlighting its advantages in phase stability and doping capability. It then systematically surveys recent developments in fabrication technologies and modification strategies for lanthanum zirconate-based porous thermal insulation materials, with particular emphasis on advances in mesostructural optimization and elemental doping methodologies. A detailed analysis is provided on the distinct mechanisms through which these approaches suppress thermal conduction and enhance high-temperature stability. Finally, this review concludes by outlining promising avenues for future research.