A plan is proposed to investigate several particulate reinforced ceramic composites that show promise of having good electrical insulation properties at temperatures approaching 3000 degrees Centigrade. In addition, good thermal shock resistance, machinability, and durability for continuous use at maximum temperature are required. Previous studies have shown that the micro-structure required for machinability and thermal shock resistance will consist of an insulation matrix surrounding disk shaped particles of a second phase. The second phase should have significantly different mechanical properties than the matrix in order to assure a high level of crack growth inhibition and crack branching. The text of the proposal provides specific recommendations of material selections that will be prepared. High temperature screening test shall be performed to assess the performance of the material specimens that are prepared. Tests shall include high temperature exposure evaluation, electrical conductivity measurements, and thermal conductivity measurements.
