Development of a Process for Producing Transparent Spinel Bodies

The need for hard, strong, high modulus transparent materials has been established, especially for windows acting as protection against armor piercing projectiles. Such a class of materials is available and includes systems containing glasses noncrystalline and ceramics crystalline. The glasses have proved insufficient because of the thickness necessary to defeat present projectiles. The ceramic materials although highly effective are at present expensive in single-crystal form and are severely size and shape limited. The development of a process that can produce ceramic materials without these limitations is the goal of the present study. The ceramic chosen for investigation was Magnesium-Aluminum Spinel Mg Al2O4, because of its acceptable ballistic properties and its cubic, isotropic, crystal structure, which assured acceptable optical properties. The experimental approach used was that of controlling material and processing parameters such that the probable attainment of transparency was maximized.