Fracture Toughness and Thermal Shock Behavior of Silicon Nitride–Boron Nitride Ceramics

Fracture toughness behavior, stress–strain behavior, and flaw resistance of pressureless‐sintered Si 3 N 4 ‐BN ceramics are investigated. The results are discussed with respect to the reported thermal shock behavior of these composites. Although the materials behave linear‐elastic and exhibit no R ‐curve behavior, their flaw resistance is different from that of other linear‐elastic materials. Whereas the critical thermal shock temperature difference (Δ T c ) is enhanced by adding BN, the content of BN has no influence on the strength loss during severe thermal shocks.