Highest UV-vis transparency of MgAl2O4 spinel ceramics prepared by hot pressing with LiF

Reaction sintering of MgO and Al2O3 with addition of LiF as sintering additive was used to prepare MgAl2O4 spinel ceramic by hot pressing. The process parameter (temperature, pressure, dwell time), the stoichiometric ratio of MgO to Al2O3 and the selection of the alumina raw powder are equally important for highest transparency of the spinel ceramic. With this optimization highest transparency of 86% in the visible range at λ = 640 nm together with UV transmission of 62% at 200 nm for spinel ceramic with 4 mm thickness was reached.