Crystallization kinetics of Al2O3-28mol%Lu2O3 glass and full crystallized transparent Lu3Al5O12-based nanoceramics

Transparent Lu 3 Al 5 O 12 (LuAG) ceramics have become very promising phosphor matrix materials due to their high doping concentration and luminous efficiency, thermal conductivity and thermal stability. However, LuAG transparent ceramics prepared by traditional powder sintering method are facing several problems, such as time-consuming and energy-consuming, complex preparation process, high quality of raw material powders and large crystalline grain size. Here we report facile elaboration of transparent LuAG-Al 2 O 3 two-phase nanocrystalline ceramics through pressureless crystallization (1000 °C, 2 h) of 72 mol.% Al 2 O 3 -28 mol.% Lu 2 O 3 (ALu28) bulk glasses combined with the crystallization kinetics analysis. The results of the crystallization kinetics analysis show that the ALu28 bulk glasses have a low activation energy (<750 kJ mol −1 ) and a crystallization mechanism of three-dimensional crystal growth mode accompanied by volume nucleation. The resulting LuAG-Al 2 O 3 ceramics with nanosized grains and dense three-dimensional network nanostructures present good transmittance (80.6 %@780 nm) and excellent mechanical properties (hardness is 24 GPa).