Synthesis of Single-Phase β-Yb2Si2O7 and Properties of Its Sintered Bulk

Single-phase beta-Yb2Si2O7 was synthesized by solid-state reaction using Yb2O3 and SiO2 gel. SiO2 gel significantly decreased the synthesis temperature and shortened the holding time. Bulk Yb2Si2O7 was obtained by pressureless sintering. Grain size, relative density (92.9%), and flexural strength [(182.3 +/- 2.0) MPa] were enhanced as the sintering temperature increased and equiaxed grains were obtained with an average grain size of approximately 3m. Bulk Yb2Si2O7 possessed a suitable thermal expansion coefficient [(4.64 +/- 0.01)x10(-6)/K] between 473 and 1573K, and the thermal conductivities at 300 and 1400K were 4.31 and 2.27W/m.K, respectively.