Effect of powder dispersity on the optical properties of HIP sintered MgAl2O4 transparent ceramics

Optical scattering centers in transparent magnesium aluminate spinel (MgAl2O4) ceramics substantially limit their applications in infrared domes or transparent windows. In this study, hot isostatic pressing (HIP) sintering was employed to fabricate high-quality transparent MgAl2O4 ceramics without the addition of sintering additive, and revealed that dispersion behavior of starting powders was crucial to the quality of MgAl(2)O(4)ceramics. Microstructural evolution and optical quality of MgAl(2)O(4)ceramics as the function of ball milling speed and presintering temperature were systematically investigated. Despite increasing ball milling speed moderated powder agglomeration, large voids were still observed from the depth direction of the sintered ceramics. These voids could be further eliminated by employing PEI as the dispersant, and the in-line transmittance of the resulting ceramic was 86.5% at 800 nm, which was almost identical to the theoretical limit of MgAl2O4.

Automated summary

In this study, high-quality transparent MgAl2O4 ceramics were fabricated using hot isostatic pressing (HIP) sintering technique, and the voids in the ceramics were successfully eliminated by controlling the dispersion behavior of powders and sintering parameters. The resulting ceramic exhibited an in-line transmittance close to the theoretical limit.