Use of Alternative Materials for Infrared (IR) Missile Domes

The object of this effort is to illustrate that ALON is a suitable, significantly lower-cost substitute to Sapphire for use as a high-speed missile dome due to the versatility of the highly developed ALON mateial processing capability and high speedoptical fabrication options. Through the application of high-speed optical fabrication processes and hard material processing technologies the intention is to demonstrate that ALON is significantly less costly to fabricate into high-speed missile domesthan that of Sapphire. The ideal replacement for Sapphire would be inexpensive to procure, easy and inexpensive to fabricate and still retain the excellent combination of optical and mechanical properties exhibited by Sapphire over the spectral rangerequired of a high-speed missile dome. Of available candidate materials, ALON comes closest to this ideal. ALON's properties are very similiar to those of Sapphire, yet ALON is transparent in it's polycrystalline form. Therefore, ALON can be made bypowder processing techniques, in larger, more complex shapes and at a lower cost than Sapphire. Furthermore, ALON's isotropic mechanical properties make it much easier and less expensive to polish using high-speed optical fabrication techniques than thean-isotropic Sapphire. ALON is also in the process of being commercialized on a large scale unlike other candidate hard materials.