Effect of Y₂O₃ addition on the densification of Yb₂Si₂O₇ by pressureless sintering

Single-phase Yb₂Si₂O₇ with a monoclinic structure was synthesized at 1550 °C for 4 h using Yb₂O₃ power and active SiO₂ gel prepared by a sol-gel method as starting materials. Yb₂Si₂O₇ ceramics were obtained by pressureless sintering of the synthesized powders. The dense Yb₂Si₂O₇ ceramic with a porosity of 3.2% was obtained by adding Y₂O₃ as a sintering aid. The microstructures, composition and morphologies of Yb₂Si₂O₇ ceramics were characterized by XRD and SEM. The results indicate that all sintered ceramics are single-phase Yb₂Si₂O₇ without any other impurity phases. The porosity significantly decreased and the sintering densification improved by adding Y₂O₃. The sample displayed granular grains in the majority with an average grain size of 1-2 μm.