A Study on the Structure, Electronic Structure, and Mechanical Properties of Three ZrO2/CeO2 Interfaces

Abstract

With the increasing demands for surface planarization, core–shell-structured CeO₂-based composite abrasives have been constructed to achieve high-quality and efficient polishing. The core–shell interface structures of abrasives are crucial to their performance. First-principles calculations were used to investigate the geometric structures, electronic structures, and mechanical properties of the m-ZrO₂(–111)/CeO₂(111), t-ZrO₂(101)/CeO₂(111), and c-ZrO₂(111)/CeO₂(111) interfaces, as well as their corresponding interfaces containing O vacancies. The results showed that the c-ZrO₂(111)/CeO₂(111) interface was the most stable with an adhesion work of 10.21 J/m^–2, and the m-ZrO₂(–111)/CeO₂(111) interface was the least stable with an adhesion work of 9.61 J/m^–2. The O vacancy formation energies of m-ZrO₂(–111)/CeO_1.92(111), t-ZrO₂(101)/CeO_1.92(111), and c-ZrO₂(111)/CeO_1.92(111) interfaces were reduced from 2.88 to 1.85, 2.78, and 1.59 eV, respectively, as compared to the CeO₂(111) surface. There were more Ce³⁺ in the interfaces containing O vacancies, and the density of states peak was close to the Fermi level, exhibiting stronger polishing activity. The stability of three ZrO₂/CeO₂ and three ZrO₂/CeO_1.92 interfacial structures is determined by the number and lengths of Zr–O and Ce–O covalent bonds generated in the interfacial region. The stress at the ZrO₂/CeO₂ interface is greater than that at the ZrO₂/CeO_1.92 interface under the same strain. The Zr–O and Ce–O bond lengths in the interfacial region decrease and the interfacial interactions increase during compression, while the Zr–O and Ce–O bond lengths in the interfacial region increase and the interfacial interactions decrease during shear, which leads to brittle fracture or structural-phase transition.