A silicon nitride reference material-A testing program of ESIS TC6

摘要

Silicon nitrides with sufficient strength for structural applications have been developed 20 years ago. A break-through in the use of these ceramics for structural applications did not yet take place. Most probably, the reason for this is a significant lack of design relevant data. TC 6 "Ceramics" of the European Structural Integrity Society (ESIS) has established a research program in order to determine a complete set of material properties and data indispensable for design for a commercially available silicon nitride ceramic. The material chosen as the ESIS Silicon Nitride Reference Material is a gas pressure sintered silicon nitride containing approx 3 wt. percent Al_2O_3 and approx 3 wt. percent Y_2O_3. The results available to the present indicate that this specific material has a good mechanical performance at room temperature and up to approx 800 deg C. Above this temperature the large amount of amorphous grain boundary phase causes a detrimental influence on the environmental assisted crack growth properties and the creep performance.