Scale-up Equipment for Nanosize Particle Synthesis
Final rept. 1 Aug 96-31 Jul 97
PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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The goal of the ARPAAFOSR supported research program is to establish a scientific foundation for the low cost preparation of bulk single crystal quality materials by templated grain growth TGG a process in which solid phase epitaxy is used to initiate solid state grain growth of a specific orientation in a polycrystalline matrix. We are investigating two classes of TGG surface TGG in which a single crystal is contacted with a dense, polycrystalline ceramic and in situ TGG in which anisometric particles are uniformly dispersed and oriented in a polycrystalline matrix. The matrix must be fully dense and consist of sub 100 nm scale grains for TGG to work. Bi4Ti3O12 and Sr2Nb2O7 have been selected because of the need for high temperature piezoelectrics. These materials can be poled only when they are highly oriented materials. We are also studying TGG for the low cost preparation of bulk single crystal quality BaTiO3 and Ba1-xSrxTiO3. This process is designed to provide large single crystals at considerably less expense than top-seeded solution grown BaTiO3 which cost on the order of 5000 per crystal Sanders Inc., Nashua, New Hampshire. Ultimately, such crystals are attractive for photorefractive applications including optical storage, phase conjugate mirrors, and multiple wave mixing.