Nucleation mechanisms in a SiO2-Li2O-P2O5-ZrO2 biomedical glass-ceramic: Insights on crystallisation, residual glasses and Zr4+ structural environment

Cicconi MR, Belli R, Brehl M, Lubauer J, Hayakawa T, Kimura K, Hirota T, Usui K, Kohara S, Onodera Y, Lohbauer U, Hayashi K, de Ligny D (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Book Volume: 42

Pages Range: 1762-1775

Journal Issue: 4

DOI: 10.1016/j.jeurceramsoc.2021.12.009

Abstract

In manufacturing reliable glass-ceramics, bulk chemistry and appropriate thermal treatments are critical points. To better understand the influence of nucleation parameters on the crystallisation behaviour and mechanical properties of multicomponent glass-ceramics, we studied the effects of time and temperature on phase stabilisation, the evolution of the crystal phases and physical properties of a Zr-rich lithium-silicate having a SiO2/Li2O molar ratio < 2. Here, we also provide insights into the structural environment of Zr⁴⁺ at the early stage of nucleation by Anomalous X-ray Scattering (AXS). By reverse-engineering a commercial material through remelting and sequential thermal treatments, we observed the strong effect of the nucleation temperature on the final mineral assemblage and of the volume fractions of the lithium-disilicate phase on the fracture toughness (KIc). Indeed, the KIc value was increased from ∼0.8 MPa.m^½ in the pristine glass up to ∼ 2 MPa.m^½, if compared to the original commercial material exhibiting a KIc value of 1.6 MPa.m^½. Furthermore, the synthesis of residual glasses at different stages of the thermal treatments allowed us to observe the changes in the glass network structure and properties. AXS was used to extract the contribution exclusively coming from Zr for different nucleation steps. The differential pair distribution functions ΔZrg(r) show two distinct peaks at ∼2.10 Å and 3.44 Å, respectively associated with Zr-O and Zr-Zr/Zr-Si correlations with the formation of edge sharing in addition to corner sharing polyhedra. It was discerned the occurrence of (sub)nano-sized clusters enriched in Zr. These local clusters do not show changes during the different thermal treatments, either for higher temperatures or longer times. No Zr phases are stabilised in the crystallised materials, suggesting that these clusters do not evolve above the critical nucleus size. All evidence points to a highly heterogeneous environment and the coexistence of three structural regions i) (sub)nano Zr-clusters, ii) P enriched μ-areas, iii) residual silicate glass. The evolution and spatial distribution of these units influence the final properties.

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Involved external institutions

Nagoya Institute of Technology / 名古屋工業大学 Nagoya Kōgyō Daigaku Japan (JP) National Institute of Materials Science (NIMS) Japan (JP) Kyoto University / 京都大学 Kyōto daigaku Japan (JP)

How to cite

APA:

Cicconi, M.R., Belli, R., Brehl, M., Lubauer, J., Hayakawa, T., Kimura, K.,... de Ligny, D. (2022). Nucleation mechanisms in a SiO2-Li2O-P2O5-ZrO2 biomedical glass-ceramic: Insights on crystallisation, residual glasses and Zr4+ structural environment. Journal of the European Ceramic Society, 42(4), 1762-1775. https://doi.org/10.1016/j.jeurceramsoc.2021.12.009

MLA:

Cicconi, Maria Rita, et al. "Nucleation mechanisms in a SiO2-Li2O-P2O5-ZrO2 biomedical glass-ceramic: Insights on crystallisation, residual glasses and Zr4+ structural environment." Journal of the European Ceramic Society 42.4 (2022): 1762-1775.

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