| Texto completo | |
| Autor(es): |
Zielasko, Wiebke
;
de Oliveira, Rafael Bonacin
;
Zanotto, Edgar Dutra
;
Hansen, Michael Ryan
;
Eckert, Hellmut
;
Bradtmuller, Henrik
Número total de Autores: 6
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ACTA MATERIALIA; v. 297, p. 11-pg., 2025-07-19. |
| Resumo | |
Multicomponent glasses containing a diverse range of element oxides are increasingly being designed using machine learning (ML) techniques to optimize their properties. These rather complex compositions present new opportunities for both fundamental research and materials development. A key challenge in ML-assisted and empirical glass design is establishing quantitative structure-property relationships (QSPRs), which serve as critical input parameters for predictive modeling. In this study, we systematically examine the contrasting structural roles of niobium oxide (Nb2O5) and lanthanum oxide (La2O3) in multicomponent silicate glasses using multinuclear solid-state NMR and Raman spectroscopy. The glass compositions, in mol%, are approximately xLa2O3-(100-x)[28(Li2O-Na2O-K2O)-12(CaO-SrO-BaO)-60SiO2] and xNb2O5-(100-x)[28(Li2O-Na2O-K2O)-12 (CaO-SrO-BaO)-60SiO2], with 0 <= x <= 10. Our results demonstrate that Nb2O5 primarily acts as a network former, integrating into the silicate framework and forming Si-O-Nb linkages, without the formation of additional non-bridging oxygen (NBO) atoms in the silicate network. The 93Nb NMR chemical shifts indicate that six-coordinate [NbO6/2]- units are formed, which are charge compensated by alkali or alkaline-earth oxides. In contrast, La2O3 functions as a network modifier, introducing approximately 3.4 NBOs per equivalent of La2O3 and decreasing the connectivity of the silicate network accordingly. While 93Nb and 139La NMR spectra suggest a relative invariance in Nb and La local environments as a function of composition, additional 7Li{93Nb} double resonance NMR experiments give evidence for non-linear changes of the Li/Nb interaction strengths. The 7Li and 23Na chemical shift trends reveal distinct interactions between Li+/Na+ and the modified glass network. These findings highlight key structural differences between Nb2O5-and La2O3-containing silicate glasses, contributing to the development of data-driven glass design strategies. (AU) | |
| Processo FAPESP: | 19/26399-3 - Elucidação de rearranjos estruturais durante o processo de relaxação e cristalização de materiais vítreos |
| Beneficiário: | Henrik Bradtmüller |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros |
| Beneficiário: | Edgar Dutra Zanotto |
| Modalidade de apoio: | Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs |