High Strength, Transparent Alumina IR Windows with Nano-scale (< 100 nm) Sintered Microstructure

This STTR Phase I project is designed to develop a novel process for fabricating a nano-grained ceramic material for infrared windows. The proposed STTR builds upon our previous Phase I (Navy) SBIR experience to minimize risks and maximize the likelihood of success. This proposed work will utilize an innovative method to fabricate nanocrystalline alumina infrared window materials with significantly improved properties than conventional alternatives. High purity, unagglomerated nano-alumina powder will be synthesized using a novel chemical precipitation route giving 4 nm alumina particles. The powders will be compacted and formed into high density green compacts to eliminate the larger pores. Densification with minimal grain-growth will be achieved as a result of plasma activated sintering. Such a customized sintering schedule is expected to result in fully dense (¡Ý 99.99%) alumina compacts with grain sizes less than 100 nm. These transparent IR windows are expected to exhibit superior mechanical strength.