Nanocomposite optical ceramics for infrared windows and domes

Currently available IR transparent materials typically exhibit a trade-off between optical performance and mechanical strength. For instance, sapphire domes are very strong, but lack full transparency throughout the 3-5 micron mid-wave IR band. Yttria is fully transparent from 3-5 microns, but lacks sufficient strength, hardness, and thermal shock resistance for the most demanding aero-thermal applications. Missile system designers must limit system performance in order to accommodate the shortcomings of available window and dome materials. Recent work in the area of nanocomposite ceramics may produce new materials that exhibit both excellent optical transparency and high strength, opening the door to improved missile performance. The requirements for optical nanocomposite ceramics will be presented and recent work in producing such materials will be discussed.