Fabrication of MgO Transparent Ceramics by Spark Plasma Sintering

Li-li Guo, Xi Sun, and Wei-na Han

DOI: https://doi.org/10.64486/m.66.1.4
Online publication date: May 22, 2026

Abstract: In this work, MgO transparent ceramics were fabricated via spark plasma sintering (SPS) with Y2O3 as a sintering aid. The effects of sintering temperature, holding time, and Y2O3 content on the densification, microstructure, and optical transmittance of the ceramics were systematically investigated. Results indicate that optimizing SPS process parameters combined with an appropriate Y2O3 addition remarkably enhances the performance of MgO ceramics. Specifically, when sintered at 1350 °C for 10 min with 1.5 wt % Y2O3 doping, the MgO ceramic achieves high relative density and a maximum in-line transmittance of 75.35 % (mid-infrared range). Mechanistically, based on XRD lattice parameter analysis and SEM microstructural observations, Y3+ ions (ionic radius: 0.89 Å) are inferred to dissolve into the MgO lattice (Mg2+ ionic radius: 0.72 Å), inducing lattice distortion that is favorable for densification and grain growth inhibition. Excess Y2O3 (beyond 1 wt %) tends to segregate at grain boundaries, exerting a grain refinement effect via the Zener pinning mechanism. This study provides an effective strategy for the low-temperature fabrication of high-transmittance MgO transparent ceramics, thereby laying a solid foundation for the development of infrared (IR) window materials.

Keywords: transparent MgO ceramics; spark plasma sintering (SPS); Y₂O₃ sintering aid; infrared window materials; densification; optical transmittance

This article is published online first and will appear in Metalurgija, Vol. 66, Issue 1 (2027).