IAM - Ceramic Materials and Technologies

Effect of intergranular glass on phase relation of Nd-alpha-sialon

  • Author:

    Zhu, B; Gu, H; Holzer, S; Hoffmann, MJ

  • Source:

    SCRIPTA MATERIALIA, 2006, Band 54, Heft 8, S. 1469-1473

Abstract

Quantitative analytical electron microscopy study of dopant distribution in the rnicrostructure of selected Nd-alpha-sialon samples revealed the presence of relatively large amounts of glassy phase at quadruple pockets, which exhibited a common composition similar to a melilite solution. Al segregants were depleted from adjacent grain boundaries to satisfy the "stoichiometry" of such glass. Existence of this glass results in significant deviation of the Nd-alpha-sialon composition from the expected values, which shifts the alpha-beta-sialon phase boundary. Only extra Nd2O3 additives enable a monolithic alpha-sialon microstructure. The absence of similar glass in Yb-alpha-sialon materials keeps the phase relations from such deviations.