The effects of β-Si3N4 on the formation and oxidation of β-SiAlON

Abstract

AbstractThe influence of the additive β-Si3N4 on the formation and oxidation of Si4Al2O2N6 during the sintering of Al, Si, and Al2O3 powders under flowing nitrogen atmosphere was examined. An increasing molar percentage of β-Si3N4 was shown to alter the morphology of Si4Al2O2N6 from a fiber-like to a rod-like structure and also shortened the time needed to form a dense, continuous oxide layer, which served as a barrier to the diffusion of O2. An optimal molar percentage of β-Si3N4 of 29.9 mol% was discovered, at which the grain growth was enhanced, and the surface area was, in turn, reduced, yielding superior resistance to oxidation. Our results provided a theoretical basis for the formation of β-SiAlON and demonstrated the potential of its use in high-temperature oxidizing environments.