JOURNAL of the Tunisian Chemical Society

Two methods of elaborating Na₅ Y Si₄, O₁₂ type ceramics are described: a solid state reaction between SiO₂, Y₂O₃, Na₂CO₃ and NH₄H₂PO₄ at 1020°C and a "sol-gel" preparation process at room temperature. Characterization of the prepared materials was carried out using various techniques: XR, IR TG and DTA. Ceramic samples Na_5-x Y Si_4-X P_x O₁₂ have been synthetised. The rate of a secondary phase (Na₃ Y Si₃ Y Si₃O₉) increases with x. Addition of 1 to 2% of NaF or LiF decreases the amount of the later phase. Ignittion of the gel at different temperature leads to Na, Y Si₃O₉ at 500 °C, whereas Na₅ Y Si₄ O₁₂ becomes visible at 700 °C and preponderant near 900 °C.

N. Fakhar-Bourguiba, L. Smiti-Dogguy, N. Gharbi

Pages 35-39