Liquid phase sintering of yttrium oxide: The effect of Al2O3 and SiO2 additives

Solid-state sintering of Y2O3 is difficult and requires high-temperature heat treatment or the use of a sintering additive. In this study, liquid-phase sintering was utilized to produce dense Y2O3 bodies with fine-grained microstructure. Al2O3 and SiO2 were added to a commercial nano-Y2O3 powder using aluminum nitrate and tetraethylorthosilicate (TEOS) as the precursors; the samples were uniaxially pressed at 100 MPa and sintered at 1500 degrees C and 1650 degrees C. The addition of the sintering aids increased the relative density of the samples sintered at lower temperatures; also, the sintering aids suppressed grain growth. The dissolution of Y2O3 into the liquid phase changes the solid-liquid interfacial energy resulting in the formation of isolated yttrium-silicate/yttriumaluminate grains and accounts for the suppression of the growth of yttria grains.

Automated summary

In this study, liquid-phase sintering was used to produce dense Y2O3 bodies with fine-grained microstructure. The addition of sintering aids increased the relative density and suppressed grain growth. The dissolution of Y2O3 into the liquid phase resulted in the formation of isolated grains, leading to the suppression of yttria grain growth.