Advanced Optic Materials for Endo-Atmospheric Seeker Windows

The MDA requires EO/IR window technology that can perform and endure under the high-temperatures and high-heating rates (thermal shock) experienced by endo-atmospheric seeker missiles.Nokomis proposes a phase-engineered spinel-based window solution that utilizes proven techniques for achieving extreme thermal shock resistance.Nokomis will produce a EO/IR transparent ceramic material that is able to mitigate and control thermo-mechanical stress through four pathways, thereby extending the thermal shock resistance of the resulting windows. These pathways are:Enhanced bulk thermal conductivityresulting in reduced thermal-stress and stress-gradients upon rapid heating.Phase boundary stress localizationinhibiting the formation of high-stress planes throughout the material that would otherwise form and serve as fracture paths.As the window material continues to rapidly heatInterphase nano-cracking will occurproviding huge stress relief and extending the thermal shock resistance of the windowThe fourth and final pathway is through controlled crack-propagationextending operational life through bulk-failureBoth the bulk-phase and the distributed phases will be selected such that the resulting window demonstrates fracture/erosion resistant on par with sapphire windows, and demonstrates better thermal shock resistance than any of the existing transparent ceramics reported in literature.Approved for Public Release | 17-MDA-9395(24 Oct 17)