Fabrication and optical properties of highly transparent MgO ceramics by spark plasma sintering

Abstract Highly transparent MgO ceramics have been prepared via Spark Plasma Sintering (SPS) at 1200 °C for 10–60 min, under a pressure of 100 MPa. All of the prepared ceramics were visually transparent and exhibited relatively high in-line transmittance. The ceramic sintered for 60 min demonstrated the highest in-line transmittance, of 60–80% in the 300 nm to 9 μm wavelength range; values that are close to that reported for MgO single crystals. Photoluminescence measurements revealed a peak located at ~360 nm, which was determined to be due to oxygen vacancy color centers induced by the reducing atmosphere of the SPS process in vacuum atmosphere.