THERMAL-SHOCK BEHAVIOR OF SI3N4 SIC COMPOSITES/

In the present study the thermal shock behaviour of Si3N4/SiC composit es with and without Y2O3 as additive was investigated using the KFA el ectron beam test facility JUDITH at energy densities of up to 9 MJ m(- 2), which is designed for disruption simulations of materials for the first wall of a fusion reactor. The influence of SiC content, microstr ucture, additive and density on thermal shock behaviour and mass loss is discussed. Composites with additive have a slightly higher mass los s rate, but show no catastrophical thermal shock behaviour as do the c omposites without additives. Samples with lower density in the system with additive revealed no visible difference in mass loss and fracture behaviour.