Pores Formation Mechanism of Undoped TiO2 Ceramics

Abstract

Formation mechanism of pores in undoped TiO2 ceramics was investigated through defects chemistry and materials testing methods. The undoped TiO2 ceramics samples were prepared from anatase TiO2 powders by a traditional solid-state sintering method. Microstructure, chemistry composition and ionic valence of undoped TiO2 ceramics were by SEM, EDS and XPS. Formation mechanism of pores was discussed by combination defect chemistry with materials structure measurement. The results show that there exist trivalence Titanium ion (Ti 3+) and grain boundaries absorbed oxygen in undoped TiO2 ceramics samples. Both content of absorbed oxygen in grain boundaries and Ti 3+ concentration increase with sintering temperature increasing. There are much gas pores in grains and grain boundarties of undoped TiO2 ceramics samples. The gas pores are mainly originated from lattice oxygen volatilization and oxygen vacancies segregation during high-temperature sintering.