Solid State Growth of Advanced Ceramic Single Crystals

The proposed experimental program demonstrates the technical feasibility of growing single crystals of technologically important ceramics by the solid state method. The proposed method relies on discontinuous grain growth which is often regarded as undesirable and deleterious during the sintering of many ceramics. In order to demonstrate the technical feasibility and versatility of the solid state method, we propose to grow single crystals of a relaxor lead magnesium niobate-lead titanate solid solution exhibiting many attractive properties for dielectric and electrostrictive applications. A single crystal will be produced by contacting a dense polycrystalline ceramics exhibiting discontinuous grain growth to a single crystal seed. This assembly will be heated at a temperature lower than the critical temperature for the onset of discontinuous grain growth. Single crystals, which are grown by the solid state method at temperatures substantially lower than their melting points, grow as the seed crystals consume grains in polycrystalline ceramics. Thus, the method is ideal for single crystal growth of ceramics having one or more components with high vapor pressure at elevated temperatures. Furthermore, because the solid state method does not require any expensive and complicated apparatuses, these single crystals cost less than those grown by conventional melt growth methods.