Process Improvements for the Production of Large-Area, Monolithic Reconnaissance Windows

This Navy Phase I SBIR Program main objective was to scale up MER"s window technology to make large, strong, monolithic windows from spinel polycrystalline ceramic up to 18"x22"during Phase I and up to 21.5"x37"during Phase II. The window manufacturing concept pursued in this project presents a solution to the Navy"s need for durable, monolithic, infrared-transmitting sensor windows with target areas up to 80x80x1.3 cm (31.5"x31.5"x0.512") for reconnaissance purposes. The size of monolithic windows is presently limited by crystal growing equipment used to make sapphire, and by the availability of large hot pressing and hot isostatic pressing equipment for spinel or AlON. The alternative approach pursued by MER in this project is to scale up MER"s standard window processes to produce strong, monolithic windows as large as 45.72 cm x55.88 cm x1.3 cm (18"x22"x0.512") during Phase I, to be scaled up to and to 80 cm x80 cm x1.3 cm during Phase II and Phase III. The excellent optical and mechanical properties of small spinel windows will be preserved in the large windows. 18"x22"spinel windows were produced during Phase I using a 450 ton hot press.