Dynamic characterization approach for the investigation of microstructural changes in clay-based materials during firing

Abstract

This work aims to understand the mechanisms occurring during the microstructural transformation of clay-based mixtures. For that, the combination of various standard and advanced characterization techniques was used. This original approach allowed an outstanding description of complex mechanisms involved during the firing, bringing new insights in regards to the state-of-the-art. Thus, the formation of viscous glassy phases and the associated effects in terms of densification acceleration were particularly revealed by following the damping of Acoustic Resonance (AR) signals and by dynamic high-temperature Scanning Electron Microscopy (SEM). Further STEM-EDX (Scanning Transmission Electron Microscopy Coupled with Energy Dispersive X-ray) analyses revealed that the glassy phase resulting from the solidification of the viscous phase is predominantly composed of silicon, aluminum, oxygen, and potassium. This study also evidenced that the behavior of a binary clay-based mixture was not always described by a mixing law model.