A Novel Route for The Production of Net Shaped Transparent Spinel for Infrared Applications

Optical quality spinel (MgAl2O4) is finding an increased number of applications for military acquisition, tracking and pointing systems as well as ground vehicle and aircraft armor. This spinel offers a lower cost substitute for presently used sapphire without compromising the needed strength for applications in infrared windows and missile domes. Lynntech Inc., proposes a novel thermo-reversible gelcasting technology which will be developed in collaboration with the Northwestern University. The technique uses low viscosity, high volume fraction ceramic suspensions that undergo a reversible gel transition at temperatures of about 60 degrees C. The wet mechanical strength of the gelled bodies is sufficient to allow them to be removed from the molds and handled without damaging the ceramic components thereby enabling this procedure in the production of objects having complex shapes. In addition, the process does not utilize toxic monomers used in conventional gelcasting methods. The wet green bodies will be dried and densified using conventional pressureless sintering techniques under special gas environment. This sintering technique limits grain growth and produces nanograin transparent ceramics, with increased strength needed for varied applications. These spinel windows can be used for a wide range of applications in the UV, visible and MWIR ranges.