Influence of temperature and time on Nd-doped silica powder prepared by the solgel process

Nd-doped silica was prepared by solgel method, using tetra-ethoxysilane and Nd(NO3)3 as precursor materials and HCl as a catalyst. The prepared samples were subjected to thermal treatment under different temperatures and time durations. Structural changes were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) spectroscopy and scanning electron microscopy (SEM). The effect of thermal annealing on structural evolution and dislocation density of Nd-containing silica has been discussed. The sample analyzed by XRD and SEM methods and both confirmed the grain size dependency on temperature and sintering time. Sintering at 900 °C (3 h) produces neodymium oxide nanocrystallite about 13 nm. However, increase in sintering temperature and time, effectively improves crystallinity, transmission spectra and morphology of the Nd-containing silica composite. Distinct structure of monoclinic Nd2O3 and Nd2SiO5 nanocrystallites with average size ∼18 nm and 24 nm were obtained at 1250 °C (6 h). It was also found that the combination of high temperature and prolonged calcination controls the dislocation density of nanocomposites.