Oxidation kinetics of hot-pressed silicon nitride

Abstract

A simplified model for evaluation of hot-pressed silicon nitride (HPSN) has been derived which accounts for the amount and type of grain boundary phase and for the composition at the Si₃N₄/oxide reaction interface. The model proved suitable for explaining the oxidation behaviour of a wide range of materials including MgO, CeO₂, (CeO₂ + SiO₂), (Y₂O₃ + SiO₂), (MgO + Y₂O₃) additives. Some deductions are also possible on how to improve the oxidation resistance of HPSN.