Infrared-Transparent Y2O3-MgO Nanocomposites Fabricated by the Glucose Sol-Gel Combustion and Hot-Pressing Technique

A glucose sol-gel combustion method has been developed to synthesize composite nanopowders with equal volume fractions of Y2O3 and MgO. The synthesis involves the generation of precursor foam containing Y3+ and Mg2+ cations via the chemical and thermal degradation of glucose molecules in aqueous solutions. Subsequent calcination of the foam gave the composite nanopowders uniform composition and surface areas of 44-62m(2)/g depending on the relative amount of glucose. Then the nanopowder with an average particle size of 19nm was consolidated by the hot-pressing technique with different sintering temperatures. The fabricated nanocomposite is mid-infrared transparent as the result of fine grains, narrow grain size distribution, and uniform phase domains. The transmittance increases with increase in the sintering temperature and reaches 83.5% at 3-5m mid-infrared wave range once the temperature reaches 1350 degrees C, which is close to the theoretical value of 85%. And it is noteworthy that the cutoff wavelength reaches 9.6m, which is superior to those of spinel, AlON, and sapphire. And the Vickers hardness of the sample reaches 10.0 +/- 0.1GPa, which is significantly higher than those of the coarse grained single-phase MgO and Y2O3. The results indicate that the glucose sol-gel combustion and hot-pressing technique is an effective method to fabricate infrared transparent Y2O3-MgO nanocomposites.