A study of the electronic structure and mechanical stability of three TiO2/CeO2 interfaces for high-quality core–shell abrasives for efficient polishing

Abstract

Due to the problems of the easy agglomeration and high polishing defect rates of pure CeO₂ particles, this study constructed a core–shell structured TiO₂/CeO₂ composite abrasive with the aim of achieving high-quality and efficient polishing. The atomic structure, electronic structure, and mechanical properties of a-TiO₂(001)/CeO₂(001), a-TiO₂(101)/CeO₂(111) and r-TiO₂(110)/CeO₂(111) interfaces and their interfaces containing O vacancies were studied using first principles calculations. The results indicated that the structural stability of the three TiO₂/CeO₂ interfaces was determined by the number and length of the Ti–O and Ce–O covalent bonds generated in the interface region. The value of adhesion work for the stable a-TiO₂(001)/CeO₂(001) interface and the most unstable r-TiO₂(110)/CeO₂(111) interface were 2.28 and 0.53 J m⁻², respectively. Oxygen vacancy defects reduced the work of adhesion and ideal shear strength of the three TiO₂/CeO_1.94 interfaces. The fracture of Ti–O bonds in the interface region was the reason for the failure of the a-TiO₂(001)/CeO₂(001) and a-TiO₂(101)/CeO_1.94(111) interfaces, while the failure of other interfaces was mainly caused by the fracture of Ce–O bonds in the interface region. Under shear strain, the chemical activities of the r-TiO₂(110)/CeO₂(111) and r-TiO₂(110)/CeO_1.94(111) interfaces were reduced.