Effect of SiO2 content on Y-TZP/Al2O3 ceramic-nanocomposite properties as potential dental applications

Abstract Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have been widely applied in fixed partial prostheses as well as dental uses i.e. a substructure for crowns. However, Y-TZP has limited applications, which is due to the presence of defects in its microstructure introduced during the manufacturing process. Accordingly, due to Y-TZP limitations, the novel (X)Y-TZP- 20Al2O3-(80-X) SiO2 (X = 65, 70 and 75) ceramic nanocomposites were successfully fabricated via the powder metallurgy method. X-ray diffraction (XRD) patterns of commercial powders showed the stabilization of monoclinic zirconia (ZM) by increasing the silica content. In order to determine the fracture load and micro-bending strength, the three-point bending test was used at ambient temperature. The fractography analysis was applied to evaluate the fracture behavior of the crack path. The Scanning electron microscopy (SEM) test was performed to study the particle size of powders and monitor the fracture surface. The obtained phases prior to the failure of ceramics were alumina, tetragonal-zirconia, and monoclinic-zirconia. Both tetragonal-zirconia and alumina were presented on the cross-section of cracked samples. The obtained results showed that the specimen with 15% silica showed the best thermal properties as well as micro-shear bonding and bending strength which prove its potential for dental applications.