Relevance of internal structures to the fracture strength of injection-molded and sintered silicon nitride ceramics

The densification behavior and fracture strength of silicon nitride ceramics were investigated for samplesmade through the injection-molding process in comparison with thosemade by powder granule compaction. Although no clear difference was observed in the density, phase composition and microstructure of sintered bodies between the processes, the fracture strength was clearly higher for the samples made through the injection-molding route. A relatively uniform internal macrostructure was considered responsible for the improved fracture strength of the injection-molded and sintered silicon nitride.