Effects of CeO₂ and nano-ZrO₂ agents on the crystallization behavior and mechanism of CaO-Al₂O₃-MgO-SiO₂-based glass ceramics

The crystallization behavior and mechanism of CaO-Al₂O₃-MgO-SiO₂ (CAMS)-based diopside glass ceramics with nano-ZrO₂ nucleators and CeO₂ agents have been investigated. The use of nanoscale ZrO₂ as nucleators is favorable to the crystallization of glass ceramic at a relatively lower temperature due to the reduction of the activation energy, while the activation energy is increased after adding the CeO₂ agent. The microstructure and orientation have been analyzed by scanning electron microscopy and electron backscatter diffraction. Two discernible layers are observed, featured in glass and crystalline phases, respectively. Remarkably textured polycrystalline diopsides are verified for the samples (A and B) free of CeO₂ agents, with c-axes perpendicular to the interface of the two layers. Comparatively, the c-axes of diopside grains of the sample (C) with CeO₂ agents are proved to be parallel to the interface. Nanocrystals are detected in the vicinity of the interface for sample C.