Our proposed research for Phase I is in response to US Navy solicitation for low-cost synthesis methods for producing nanocrystalline ceramics to offer the best properties for modem technological applications. We propose to process high purity unagglomerated and engineered nanocrystalline AIN as a model material, by a low-cost method called Gas Phase Combustion Synthesis (GCS) to combat two key issues obstructing full-scale AIN commercialization: I) the cost and, (ii) purity. Our AIN synthesis route involves a sodium-flame process together with a NaCl coating technique that prevents agglomeration. The byproduct-coating approach for controlling the particle size, agglomeration and oxidation, is novel and holds great promise for commercialization. The process is equally applicable for synthesis of a variety of ceramics, metals and composites and is attractive because scale-up is straightforward. Although, synthesis of AIN is the major thrust of this proposal, we plan to demonstrate the occurrence of superplasticity in nanocrystalline AIN by non-traditional elevated temperature compression testing to corroborate the general notion that superplasticity, although not exhibited by ultrafine AIN (-O. I ym) can indeed be possible in fully consolidated nanocrystalline AIN.
