Effect of TiO2 addition on microstructure of zirconia/alumina sintered ceramics.

The present work investigates the influence of TiO 2 additions on sintering behavior of Al 2 O 3 , ZrO 2 (12 mol% CeO 2 ) and Al 2 O 3 -ZrO 2 (12 mol% CeO 2 ) ceramics for dental applications. Alumina-Titania, Zirconia-Titania and Titania-Alumina-Zirconia powder mixtures were uniaxially pressed and pressureless sintered at 1400 °C for 2 h. The phase composition and distribution, densification and microstructures of ceramic composites were evaluated by using X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). According to the results, an appreciable increase of alumina and zirconia density by adding only 0.27 wt% TiO 2 was observed. A continuous increase of density of alumina with titania was observed, while an opposite trend was found for zirconia. Furthermore, as indicated by XRD analysis, nano-TiO 2 addition has greatly influenced the phase composition and distribution, stimulating the formation of mixed phases in binary and ternary ceramics systems. SEM proved that TiO 2 content played major roles in controlling the porosity rate and geometry and the grain growth in different ceramic composites. [ABSTRACT FROM AUTHOR]