“…It was considered that particle size (less than 100 nm) and spherical particle shape were the two important requirements, which enabled close contact among powder particles during the sintering process, leading to fully densification of polycrystalline bulk specimen [6]. Various methods have been developed for the preparation of Lu 2 O 3 powders with satisfied microstructural features [7,8], such as combustion synthesis [9], molten salts route [10], solid state reaction [1,2], hydrothermal synthesis [11,12], and co-precipitation processing [13]. Zych et al [14,15] in the combustion process, severe agglomerations between adjacent particles could not be avoided, coupled by severe particle growth during annealing at higher temperatures.…”