Synthesis of Ultrafine Silicon Carbide

Nanosize, non-oxide ceramic powders such as silicon carbide and its composites, are desirable for use as components in high-power microelectronic devices and tubes, sensors, optical mirrors, filters, nozzles, panels and sheets in many energy related applications. The properties required for these applications include high-temperature strength, high thermal conductivity, low thermal expansion, lightweight, wear resistance, and excellent fracture thoughness to survive in the harsh environments in which they operate. Existing methods for manufacturing such nanopowders include press-and-sinter, hot isostatic pressing, reaction bonding, chemical vapor infiltration, and hot pressing. However, these methods developed to cope with typical ceramic materials having particle sizes of 1-5 um have required the addition of low-melting sintering aids and long sintering times which cause undesirable properties concurrent with unacceptable costs in manufacturing these powders. In this Phase I effort, we propose to synthesize nanocrystalline silicon carbide employing a dual-stage process. These powders will be rapidly concolidated enabling the achievement of near-theoretical density, in a very short time, at substantially lower processing parameters thereby resulting in considerable savings in manufacturing and processing costs. The ability to improve the formability of these nanoceramics will be an added advantage in the fabrication of components. Phase I will focus on demonstrating the synthesis, consolidation, and characterization while Phase II will concentrate on optimization of process-structure-property parameters that will be used to produce prototype components for use in a variety of applications. Phase III efforts will focus on the commercial production of these nanoceramic powders and the development of strategic industrial partners.