Development and characterization of Enstatite glass-ceramic via controlled heat treatment

• Grant number: 16/24509-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2017
• Effective date (End): August 26, 2018
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Edgar Dutra Zanotto
• Grantee: André Luchetti Cortada
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass, AP.CEPID

Abstract

An analysis of glass-ceramic research and commercialization by our group suggests that development of new glass-ceramics for biomedical applications is of great importance. Our comprehensive reviews on history, trends and commercial bioactive and inert glass-ceramics recently revealed that persistent competition exists among dozens of companies and academia to develop new bioactive glass-ceramics (BGCs) or restorative dental glass-ceramics (RDGCs). A main driving force for this endeavor is to improve the fracture toughness, Kic, of these materials because their Kic (1-2 MPa.m^(1/2)) is still low compared to that of the cortical bone and tooth (2-12 MPa.m^(1/2)). A tough bio-glass-ceramic can be reliably used in restoration, reconstruction or even regeneration of bone and teeth. Therefore, many different toughening mechanisms, such as transformation toughening, bridging, micro cracking, pull out, etc. are envisaged to reinforce glass-ceramics via controlled crystallization of different crystals, e.g. enstatite, diopside, wollastonite, etc. According to G.H. Beall, an enstatite glass-ceramic shows high fracture toughness of 4 MPa.m^(1/2), and the unique toughening ability of enstatite is attributed to transformation twinning, which occurs under sheer stresses. With these conditions in mind, a new glass composition in SiO2-MgO-TiO2-Na2O system has been recently developed in our center (www.certev.ufscar.br) to produce enstatite glass-ceramics. The primary results are promising and the glass-ceramic indeed shows internal nucleation of enstatite. Nonetheless, the optimization of the process is still necessary, and the crystal size and the amount of residual pores should decrease. Therefore, the objective of this project is to optimize the process variables and optimize crystal size and decrease the porosity content. (AU)