Effect of Crystallization of the Grain‐Boundary Phase on the Thermal Diffusivity of a Sialon Ceramic

Abstract

Crystallization of the glassy grain‐boundary phase in a series of sialon ceramics fabricated using a range of hot‐pressing schedules increased the thermal diffusivity at room temperature by an average of ∼10%. For samples made by a given hot‐pressing schedule, the relative difference in thermal diffusivity between composites containing a glassy grain‐boundary phase and those in which this phase had crystallized decreased with increasing temperature. This behavior is attributed to enhanced phonon scattering in the crystalline grain‐boundary phase.