Titanium and niobium: two important but enigmatic elements in glass science

• Grant number: 22/14232-0
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2023
• End date: June 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Agreement: University of Bath
• Mobility Program: SPRINT - Projetos de pesquisa - Mobilidade
• Principal Investigator: Hellmut Eckert
• Grantee: Hellmut Eckert
• Principal researcher abroad: Philip Stephen Salmon
• Institution abroad: University of Bath, England
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass, AP.CEPID

Abstract

Titania (TiO2) and niobia (Nb2O5) are important components in commercial glass and glass-ceramic materials. Little is known, however, about the structural role that they play and how the physical properties are affected by the structural organization. A central issue is their chameleon-like nature in that both elements have an ability to transform their structural identity by changing the A-O (A = Ti or Nb) coordination number from 4 to 6 or beyond. The objective of this proposal is to elucidate these structural roles by combining neutron and x-ray diffraction with solid-state nuclear magnetic resonance (NMR) spectroscopy (USP). The nuclear isotopes 47Ti and 93Nb both have large electric quadrupole moments which strongly influence the solid-state NMR line shapes of these nuclei, due to the presence of a wide distribution of local electric field gradients in the glassy state. The results will provide fundamental information on the glass structure and crystal nucleation. They will therefore contribute to the overall aim of uncovering the key factors and design rules for accelerating the construction of new materials with the desired characteristics. (AU)