Formation of Chemically Complex Intergranular Glass Film: An Effective Strategy to Hinder Grain Coarsening

Thermally driven grain coarsening is a commonly encountered issue in nanocrystalline ceramics, particularly in high-temperature environments. The intergranular glass film (IGF) constitutes a crucial component of most ceramics and plays a pivotal role in the process of grain coarsening. In this study, it is proposed to impede grain coarsening by constructing a chemically complex IGF comprising multiple dopants with distinct ionic radii. Ternary dopants encompassing Al³⁺, Y³⁺, and La³⁺ ions are simultaneously incorporated into a ZrO₂–SiO₂ nanocomposite. To fabricate the nanocomposite, an amorphous precursor powder with uniformly dispersed dopants is prepared using a chemical coprecipitation method, followed by rapid hot pressing to obtain a dense bulk sample. The distribution behavior of ternary dopants at IGFs between adjacent ZrO₂ nanocrystallites (NCs) is carefully examined. It is revealed that the ternary dopants coexist at the IGFs. Moreover, Si⁴⁺ ions exhibit preferential enrichment at the IGFs. Remarkably, the presence of chemically complex IGFs significantly enhances the resistance to grain coarsening in ZrO₂ NCs up to 1000 °C. In these findings, valuable insights are offered for designing and fabricating nanocomposites with exceptional resistance against grain coarsening.