Transparent Spinel Fabricated from Novel Powders: Synthesis, Microstructure and Optical Properties1

Magnesium aluminate spinel powders have been synthesized from boehmite by a unique method in which Mg2+ ions are metal exchanged into the boehmite surfaces. Excellent control over the starting particle size, size distribution, purity and stoichiometry of the Mg-doped boehmite powder is possible by this method. The microstructures as well as the optical properties of dense, hot-pressed spinel are examined with the goal of better understanding the overall densification mechanisms and how they relate to the amount of LiF added to promote densification. Extreme sensitivity of the microstructure and transparency to the purity of the starting powders is shown