1 INTRODUCTION Silicon nitride ceramics have been used in various engineering applications, such as bearings,1 turbochargers,2 and cutting tools.3 Recent developments address plasticity,4 wave-transparency,5 and biocompatibility.6 The conventional fabrication of silicon nitride ceramics follows the powder-metallurgical route,7, 8 not least due to the low self-diffusion coefficient of Si3N4.9 The choice of sintering aids impacts microstructure and grain morphology, and, consequently, the...
