Synthesis and characterization of porous Y2SiO5 with low linear shrinkage, high porosity and high strength

Abstract

The emerging porous Y2SiO5 ceramic is regarded as a promising candidate of thermal insulator owing to its very low thermal conductivity. However, recent works on porous Y2SiO5 are confronted with severe problems such as large linear shrinkage (18.51–20.8%), low porosity (47.74–62%) and low strength (24.45–16.51MPa) at high sintering temperatures (1450–1500°C). In this work, highly porous Y2SiO5 ceramic with low shrinkage and excellent high-temperature strength was fabricated by in-situ foam-gelcasting method at 1550°C. The as-prepared sample has unique multiple pore structures, low linear shrinkages of 6.3–4.5%, controllable high porosities of 60.7–88.4%, high compressive strengths of 38.2–0.90MPa, and low thermal conductivities of 0.126–0.513W/(mK) (porosity: 87.1–60.2%). The effects of relative density on relative strength, as well as porosity on thermal conductivity were quantitatively discussed. The present results indicate that porous Y2SiO5 is the potential high-temperature thermal insulation material of light weight, low thermal conductivity, and high strength.