Synthesis and densification of lutetium pyrosilicate from lutetia and silica

Cerium-doped lutetium pyrosilicate (Lu2Si2O7:Ce) powder was synthesized by solid state reaction of Lu2O3 and SiO2. Stoichiometric mixtures of the starting materials were heat treated at various different temperatures and their phase contents were measured by XRD technique. It was found that the first step in the formation of Lu2Si2O7 (LPS) is the appearance of Lu2SiO5 (LSO). This takes place at 1100 °C, fully 300 °C below the first appearance of LPS. Between 1400 and 1500 °C both LSO and LPS coexist in the calcined batch, but by 1550 °C all LSO is completely converted to LPS. LPS formation temperature does not have appreciable effect on the density of the hot pressed samples. Hot pressed samples obtained from powder synthesized at 1650 °C are nearly transparent, although the particle size of the starting powder is higher than that of the powder formed at lower temperatures.