Papers by Keyword: TiO₂ Ceramic

Abstract: Microstructures and crystal structures of the second phases YNbO₄ and YTiNbO₆ in (Y,Nb)-codoped TiO₂ ceramics were investigated at different sintering temperature and calcination temperature. The (Y,Nb)-codoped TiO₂ ceramics and the second phase ceramic samples were prepared by the traditional electronic ceramic process. The microstructure, chemical composition and crystal structures of samples were characterized by SEM, EDS and XRD. The results show that there exist second phases of YNbO₄ and YTiNbO₆ in (Y,Nb)-codoped TiO₂ ceramic. With the sintering temperature and calcination temperature rising, the second phase YNbO₄ will transmit to YTiNbO₆.

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.

Abstract: Extrusion is a perspective forming technology for obtaining objects with certain profile, important for the TiO2 application as biomaterial. Extruded samples were calcinated at 1100 °C, thermally treated in different atmospheres: at 1450 °C in air and at 1300 °C in vacuum. An approach was made to examine the adhesion and colonization intensity of Staphylococcus epidermidis and Pseudomonas aeruginosa on TiO2 ceramic in vitro. It was found that Ps.aeruginosa demonstrated higher adhesion and colonization intensity as S.epidermidis and TiO2 samples treated in vacuum demonstrated higher attachment of microorganisms as TiO2 samples treated in air. It was supposed that surface charge promoted the bacterial adhesion on the vacuum treated samples.