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 deg. 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 deg. 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 deg. C for 6 h the samples show distinct formation of Nd2O3 nanocrystallites with average size ∼16 nm