Spark plasma sintering of Y2O3–MgO composite nanopowder synthesized by the esterification sol–gel route

The esterification sol–gel processed Y2O3–MgO composite nanopowder with an average grain size of 13 nm was consolidated by spark plasma sintering. The fabricated nanocomposite ceramic is mid-infrared transparent as the result of fine grains, narrow grain size distribution and uniform phase domains. The grain size increased dramatically with the increase of sintering temperature. For the Y2O3–MgO nanocomposite ceramic sintered at 1100 °C, the optical transmittance was greatly improved after the annealing process because of the relief of residual stress, carbides and oxygen vacancies.