Based on observations of the influence of calcination temperature and annealing time on the synthesis of Lu2Ti2O7 powders under molten salt conditions, a new route for preparing nano-ceramic powders from oxides, two-step calcinations (TSC), is suggested in this paper. Moreover, the TSC process was investigated in detail using XRD and SEM technologies. Commercial ceramic oxide powders TiO2 (particle size 20 nm) as well as Lu2O3 (particle size 3-4 um) were used as the raw materials and further calcinated with different heating schedules. The results showed that TSC could retard the grain growth and accelerate the phase transformation of Lu2Ti2O7 more effectively in comparison with single-step calcination (SSC). By controlling the calcination temperature and time, spherical Lu2Ti2O7 powders with nano-sized particles were achieved from oxide precursors by TSC.

Keywords: A Powders-solid state reaction, A. Grain growth, A Calcination, B. Grain size.