Structural role of titanium in glass and glass-ceramic materials
Titania (TiO2) is a critical component in commercial glass and in glass-ceramic materials. Little is known, however, about the structural role that Ti plays. A central issue is the chameleon-like nature of Ti, which has an ability to transform its identity from a network forming to a network modifying role via a change in the Ti-O coordination number from 4 to 6, and the lack of sensitivity of 47Ti or 49Ti nuclear magnetic resonance (NMR) spectroscopy. The main objective of this proposal is to elucidate the structural role of titanium by combining neutron and x-ray diffraction with x-ray absorption spectroscopy (XAS) methods. Two key features of TiO2 will be investigated, namely its role in (i) glass formation and (ii) nucleating fine-grained glass-ceramics.
The systems to be investigated are high refractive index glasses in the K2O-TiO2-P2O5 system and optically transparent glass-ceramics based on the spinel-forming ZnO-Al2O3-SiO2 system. The results will provide underpinning fundamental information on glass-forming ability and on 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. The project will benefit from an extensive package of training and skills development opportunities.