Effect of growth temperature on the structural of Nd-doped silica prepared by the chemical method

Silica gel doped with Nd2O3 was prepared by solgel method, using tetra-ethoxysilane and Nd (NO3)3 as precursor materials and HCl as a catalyst. The prepared samples were submitted to thermal treatments in the temperature range from 600 up to 1200 °C. Structural changes were investigated by XRD, FTIR spectroscopy and SEM. The effect of thermal annealing on Nd-containing silica has been discussed in detail. At 900 °C (4 h) various structures formed, while a further increase of the temperature and annealing time resulted in the formation of cubic neodymia and neodymium disilicate crystallites. At constant sintering temperature 1200 °C for 6 h the samples show distinct formation of Nd2O3 nanocrystallites with average size ∼16 nm.