Lanthanum hexaaluminate is a potential candidate for thermal barrier coatings due to its unique lamellar structure and excellent thermophysical properties. In this work, lanthanum hexaaluminate was prepared by a solid-state reaction synthesis at 1600 ^oC, and the effects of aluminum source type and molding method on the phase composition and microstructure of the powder were studied. It can be seen that the synthesis efficiency of alumina as aluminium source is higher than that of aluminium hydroxide. However, the flake structure is more obvious when aluminium hydroxide is used to synthesize aluminium hydroxide. In addition, the process of compacting green compact can effectively improve the synthesis efficiency of LaAl₁₁O₁₈, but it will also affect the formation and growth of grains. Consequently, a high yield of LaAl₁₁O₁₈ powder with a particle size of 3 μm and aspect ratio of 9.88 can be obtained by compacting aluminum hydroxide as the aluminum source

Keywords: Lanthanum hexaaluminate, Crystalline grain growth, Plate-like structure, Thermal barrier coatings