Effect of SiO2 on the sintering of cerium-doped lutetium oxyorthosilicate

Abstract We present the effect of silica on the preparation of dense Lu2SiO5:Ce (LSO:Ce) compacts. Powders of LSO:Ce were first obtained by combustion synthesis and characterized by thermal analysis, indicating the presence of free amorphous silica in amounts approaching 5 wt%. Calcination treatments at a variety of temperatures resulted in the partial volatilization of the silica and the formation of B-type LSO. However, higher temperatures enhanced agglomeration and particle growth, which can be problematic during the sintering process as it impedes full densification. During subsequent sintering of the powders, evaporation of residual silica may impede full densification and assist the formation of pores, thus an understanding of the presence of silica is important for sintering these materials. Powders calcined at a temperature of 1773 K and densified by spark plasma sintering showed the highest photoluminescence emission intensity. At this temperature there is a trade-off between decreasing electron trap density and oxidation of cerium ions.