Effects of different sintering additives on the synthesis of γ-Y₂Si₂O₇ powders

Pure γ-Y₂Si₂O₇ powders were synthesized by the solid-liquid reaction method using Y₂O₃ and SiO₂ powders with Li₂O, MgO or Al₂O₃ additives. The effects of the metallic ions Li⁺, Mg²⁺ and Al³⁺ on the synthesis process were systematically investigated by X-ray diffraction and differential scanning calorimetry. The chemical kinetics of the Y₂Si₂O₇ synthetic process was calculated to illuminate the influences of the different metallic ions on the formation of silicate. The results indicate that the additives could effectively reduce the synthesis temperature by 100–300 °C. The apparent activation energy of the synthetic reaction was reduced by 79.75%, 65.16%, or 56.77% when 6 mol.% of Li₂O, MgO, or Al₂O₃ was added, respectively, and the reaction rate was also significantly increased.