Effects of Pressure during Preparation on the Grain Orientation of Ruddlesden-Popper Structured BaLa₂Ti₃O₁₀ Ceramic

As potential thermal barrier coating (TBC) materials, Ruddlesden-Popper structured BaLn₂Ti₃O₁₀ (Ln = rare earth) compounds possess excellent phase stability and desirable thermo-physical properties as well as interesting anisotropic structure. In this paper, the effects of pressure during BaLa₂Ti₃O₁₀ (BLT) bulk preparation on the grain orientation were investigated. BLT grains exhibited lamellar structure, but the grain orientation depended strongly on the existence of pressure during bulk preparation. When pressure was applied, BLT grains preferentially grew along pressing direction, leading to formation of the texture parallel to pressing direction, but BLT grain orientation became relatively random when pressure was absent. However, in the small scale area, BLT grains grew preferentially along c-axis with independence on pressure during preparation. Pressure affected BLT grain orientation at the rapid growth stage according to the grain growth model of BLT.