Sol-gel combustion synthesis of Sc2O3-MgO nano powders using mixed fuels of citric acid and glycine for producing mid-infrared transparent nanocomposite ceramics

As a novel mid-infrared optical material, the application of Sc2O3-MgO nanocomposite ceramics is limited by optical transparency. In the present study, the influence of MgO doping in Sc2O3 on the microstructure evolution in Sc2O3-MgO system was analyzed. At least 0.1 wt% Mg2+ ions will dissolve in the Sc2O3 lattice, resulting in weakened pinning effect and defect reactions, this significantly affects the grain growth of Sc2O3. A method to refine the microstructure of Sc2O3-MgO nanocomposite ceramics was proposed, which involves combining the combustion characteristics of different fuels. By adjusting the ratio of citric acid to glycine to 5:95 mol%, the Sc2O3-MgO nanocomposite powders synthesized and subjected to hot pressing sintering obtain Sc2O3-MgO nanocomposite ceramics with similar grain size distribution. On this basis, by further adjusting the fuel ratio & Fcy; = 0.7, which reduces the agglomeration of nanopowders, successfully synthesizing Sc2O3-MgO nanocomposite ceramics with a transmittance of 72%-85 % in the range of 3.5-6.3 mu m.