Interfacial Characterization of Silicon Nitride Powders


  • Presented at the 89th Annual Meeting of the American Ceramic Society, Pittsburgh, PA, April 29, 1987 (Basic Science Division, Paper No. 163-B-87).

  • Supported by the Swedish Board for Technical Development.


The composition of the surface and the behavior in aqueous suspensions of three silicon nitride powders were investigated using electron spectroscopy for chemical analysis (ESCA), potentiometric titrations, leaching experiments, and electrophoretic mobility. ESCA shows that the as-received powders have a surface-layer composition similar to that identified as an intermediate state between silica and silicon oxynitride. The original differences in pHiep between the three powders disappears by aging the powders. The common pHiep of 6.8 ± 0.3 for the three powders is interpreted as the equilibrium pHiep for silicon nitride in aqueous suspensions.