Thermal Stability of Lutetium Aluminates at High Temperatures and in Different Media

The combination of technically useful physicochemical properties allows the use of materials based on lutetium aluminates as lasers and scintillators in calorimetry in high energy physics and in medical diagnostics. Synthesis of single crystals based on lutetium aluminates LuAlO 3 and Lu 3 Al 5 O 12 is carried out in inert, inert-reducing media, and in vacuum. In this study, the stability of lutetium aluminates in the Lu 2 O 3 –Al 2 O 3 systems is studied for the first time by differential thermal analysis up to 2100°C followed by X-ray phase analysis in a helium atmosphere and dynamic vacuum. A comparative analysis of the behavior of lutetium aluminates with the previously obtained data in air and in an argon-hydrogen atmosphere is carried out. We use single crystals of LuAlO 3 (structural type of perovskite) and Lu 3 Al 5 O 12 (structural type of garnet) obtained by the Bridgman method. Lu 4 Al 2 O 9 polycrystals (monoclinic structure) are synthesized by melt quenching.