Research Progress on Synthesis Methods and Processes of La₂Zr₂O₇ Powder for Thermal Barrier Coatings and Other Applications

With the continuously increasing performance requirements for high-temperature structural materials in aerospace, energy, and other fields, traditional 8YSZ (8 wt% yttria-stabilized zirconia) thermal barrier coating (TBC) materials have gradually revealed limitations such as insufficient phase stability at elevated temperatures and rising thermal conductivity, making them inadequate for extreme service environments like next-generation high thrust-to-weight ratio engines. La₂Zr₂O₇, as a typical A₂B₂O₇-type rare-earth zirconate, exhibits promising potential in TBC applications due to its low thermal conductivity, (~1.2 W·m^-1·K^-1@1000℃), high melting point (~2300℃), high-temperature structural stability, and excellent sintering resistance. High-performance powder serves as the foundation for preparing high-quality coatings, and extensive research has been conducted on La₂Zr₂O₇ powder synthesis. This paper systematically reviews the main synthesis methods for La₂Zr₂O₇ powder, including solid-state reaction, chemical co-precipitation, sol-gel, self-propagating high-temperature synthesis (SHS), and molten salt synthesis, analyzing their characteristics and applicability in terms of synthesis conditions, powder morphology, and phase structure control. Furthermore, the influence mechanisms of La₂Zr₂O₇’s crystal structure on its thermophysical properties are explored, with emphasis on the intrinsic relationship between preparation processes and structural evolution, as well as the impact of crystal structure variations on its TBC performance parameters (e.g., thermal conductivity, thermal stability, and thermal shock resistance). Current challenges and unresolved issues in research are identified, and future directions are proposed. This work aims to provide theoretical insights and technical references for advancing La₂Zr₂O₇ powder research and engineering applications.