Materials and Energy Research Center (MERC) Iranian Ceramic Society (ICERS) Advanced Ceramics Progress 2423-7477 6 1 2020 03 01 Crystal Structure and Lattice Parameter Investigation of La3+ Substituted CeO2 in LaxCe1-xO2-X/2 Synthesized by Solid-State Method 43 48 106445 10.30501/acp.2020.106445 EN A. M. Fathi Dehkharghani Ceramics Department, Materials and Energy Research Center, Meshkin Dasht, Alborz, Iran M. R. Rahimipour Ceramics Department, Materials and Energy Research Center, Meshkin Dasht, Alborz, Iran 0000-0001-5840-0339 M. Zakeri Ceramics Department, Materials and Energy Research Center, Meshkin Dasht, Alborz, Iran 0000-0001-5551-4912 Journal Article 2019 12 16 Lanthanum (La) doped Ceria (CeO₂) has attracted considerable interest as a candidate material for thermal barrier coating (TBC) because of its low thermal conductivity and potential capability to be operated above 1250^°C. In this study, La₂Ce₂O₇ powder was synthesized through the ball mill method. The crystal structure of La³⁺ substituted CeO₂ solid solution was investigated by X-ray diffraction in La_xCe_1-xO_2-x/2 (0<x< 0.5). The fluorite structure of CeO₂ did not change although La³⁺ was the largest trivalent rare-earth ion. The lattice parameter changed from 5.41 to 5.59Å by increasing La content. Changes in the lattice parameters of La_xCe_1-xO_2-x/2 that were compared with the theoretical values measured by XRD were obtained based on the oxygen vacancy model. The theoretical lattice parameters were larger than the lattice parameters calculated from the X-ray diffraction pattern. Moreover, the Williamson–Hall equation was used to measure the crystallite size and strain in the La_xCe_1-xO_2-x/2 lattice as a function of the lanthanum content. The results showed that the presence of lanthanum in the structure reduced the crystallite size. https://www.acerp.ir/article_106445_fd6db04cd5c83c72e26625f063595d2c.pdf