Abstract: Polycrystalline alumina and methods for manufacturing polycrystalline alumina exhibiting improved transmission in the infrared region. In one embodiment, polycrystalline alumina articles are formed by providing a powder of substantially alpha phase alumina having a grain size of up to about 1 ?m, dispersing the powder in a liquid to form a slurry comprising powdered solids and liquid, removing excess of the liquid from the slurry to form a body, heating the body to provide a densified body, hot isostatically pressing the densified body under conditions to provide an article having a density of at least about 99.9% of theoretical density, and optionally annealing the article, wherein one or more of the annealing or heating are performed in an inert, dry gas.

Abstract: Polycrystalline alumina and methods for manufacturing polycrystalline alumina exhibiting improved transmission in the infrared region. In one embodiment, polycrystalline alumina articles are formed by providing a powder of substantially alpha phase alumina having a grain size of up to about 1 ?m, dispersing the powder in a liquid to form a slurry comprising powdered solids and liquid, removing excess of the liquid from the slurry to form a body, heating the body to provide a densified body, hot isostatically pressing the densified body under conditions to provide an article having a density of at least about 99.9% of theoretical density, and optionally annealing the article, wherein one or more of the annealing or heating are performed in an inert, dry gas.

Abstract: Polycrystalline alumina and methods for manufacturing polycrystalline alumina exhibiting improved transmission in the infrared region. In one embodiment, the percent real in-line transmittance is within about 2% of sapphire at selected wavelengths. In one or more embodiments, polycrystalline articles exhibit improved mechanical properties such as thermal shock resistance and hardness, which may find use in armor applications.