Experimental glass-infiltrated alumina-zirconia composites: characterization of microstructure, optical and mechanical properties

• Grant number: 19/08693-1
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): July 01, 2019
• Effective date (End): June 30, 2021
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Estevam Augusto Bonfante
• Grantee: Edmara Tatiely Pedroso Bergamo
• Home Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil
• Associated research grant: 12/19078-7 - Development and processing of Al2O3-ZrO2 translucent composite for CAD/CAM monolithic prostheses: the effect of aging on biaxial flexural strength, AP.JP

Abstract

The glass infiltration in polycrystalline ceramic systems allows for better optical and mechanical properties, as well as, adhesion by silanization methods. Although such advantages have already been proven for zirconia, this material is susceptible to low temperature degradation (LTD). This problematic was the rationale behind the Young Investigator proposal #2012/19078-7 and has motived the development of zirconia-alumina composites (zirconia-toughened alumina - ZTA and alumina-toughened zirconia - ATZ). Preliminary data related to the development of a LTD-resistant ZTA composite with unaltered optical and mechanical properties have already been reported to FAPESP. Thus, this project seeks for the development of an additional innovation through the glass infiltration of ZTA and ATZ composites and the characterization of the optical and mechanical properties before and after the hydrothermal aging. Experimental ZTA 80%Al2O3-20%ZrO2 and ATZ 20%Al2O3-80%ZrO2 composites will be synthetized and infiltrated with specifically-formulated glasses. After sintering and polishing, half of the specimens will be aged and characterized by energy dispersive x-ray spectroscopy (EDS), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD). The density will be determined and the optical properties will be evaluated in a spectrophotometer. The hardness and fracture toughness will be measured using Vickers indentation test. The elastic modulus gradient through nanoindentation. The biaxial flexural strength test will be conducted for knowledge of survival probability, Weibull modulus and characteristic strength.