Redistribution of dopants between amorphous and crystalline phases in ZrO2–SiO2 nanoceramics

Abstract

AbstractExtensive efforts have been devoted to investigate the distribution of dopants in ceramics. However, one critical question remained barely explored, which is the redistribution of dopants between amorphous and crystalline phases during fast sintering of ceramics. Here we address this gap by observing the redistribution of five selected dopants (Y, Ce, Yb, Hf, and Ta) in ZrO2–SiO2 nanoceramics during sintering. We designed two groups of experiments: In group one, dual‐phase amorphous particles were sintered with multicomponent crystalline ones. The former particles were ZrO2–SiO2 glass, whereas the latter ones consisted of ZrO2 solid‐solution nanocrystallites (SSNCs) embedded in an oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. In group two, dual‐phase crystalline particles were sintered with multicomponent amorphous ones. The former particles were composed of ZrO2 nanocrystallites (NCs) embedded in an amorphous SiO2 matrix, whereas the latter ones were oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. Redistribution of the dopants from the glass to ZrO2 NCs occurred in the two groups, that is, the five dopants migrated from the glass matrix into the ZrO2 NCs, forming ZrO2 SSNCs. The redistribution of the dopants not only increased the configuration entropy of the ZrO2 NCs but also benefited the network structure integrity of SiO2 glass. The dopant redistribution process was driven by the minimization of the studied material's free energy. The reported results are important for understanding the redistribution behaviors of dopants and are expected to provide new insights to design new ceramics via the multielement co‐doping strategy.