Formation of Ring-Like Si-O-Zr Bonds at Intergranular Interfaces in Silica-Doped Zirconia

Possible cluster models of the intergranular interfaces phase for SiO2/ZrO2 binary oxides were optimized by the density‐functional theory (DFT/B3LYP). New results on the formation of the interfacial ring‐like Si–O–Zr bonds are validated by the analyses of reaction Gibbs free energies and computational infrared vibration spectra. Moreover, the Mulliken charge population of interfacial Si–O–Zr structures shows that the increased temperature and critical size of the tetragonal‐to‐monoclinic phase transformation for SiO2‐doped ZrO2 mainly come from the reduced charge of oxygen atoms located at the interface and coordinated with the neighboring zirconium atoms, which accords well with the previous theoretical results.