Effects of Y2O3 additive percentage on MgO ceramic by Co-Precipitation and SPS methods

Highlights: • Nanopowder prepared by the co-precipitation and formed by the SPS methods. • MgO5%Y₂O₃ had the highest lattice parameter and MgO10%Y₂O₃ had the smallest particles size. • Y₂O₃ additive improved density and hardness in low amounts, but it decreased them in high amounts. • The best transmittance properties belonged to MgO-2.5%Y₂O₃ sample. MgO nanopowders were synthesized through the co-precipitation method with different Y₂O₃ percentages (0, 2.5, 5, and 10 wt %). The nanocomposite powder was characterized by thermal gravimetric-differential thermal analysis (TG-DTG-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and field-emission scanning electron microscope (FESEM) analysis. Y₂O₃ can have positive effect on synthesis and sintering of MgOY₂O₃ ceramic likewise particles size and densification process. Crystallite size decreased with increasing amount of Y₂O₃ additive, and it was 32.6 nm for MgO-10%, and the average particle size by FESEM image was 52.2 nm for this sample. Lattice parameter increased (from 4.2188 to 4.2243 A⁰) by increasing the additive percentage from 0 to 5%, but it decreased (4.2195 A⁰) in 10% additive. Nanopowder was sintered by the SPS technique at 1400$\mathrm{°C}$. MgO-2.5% sample had the highest relative density (99.1%) and transmittance (15%), with an average grain size of 0.41 μm. MgO-5% sample, however, had the highest hardness (10.57 GPa), thanks to the finer average grain size (0.25 μm).