Glass-ceramics and realization of the unobtainable: Property combinations that push the envelope

Davis, Mark J.; Zanotto, Edgar Dutra

doi:10.1557/mrs.2017.27

Cited by 59 publications

(38 citation statements)

References 10 publications

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“…The formation of glass-ceramics exhibiting valuable mechanical, electrical and optical properties is mainly dependent on crystal nucleation, and growth and, in some cases, to obtain a glass-ceramic, adding small amounts of nucleating agents is required (heterogeneous nucleation) [ 83 , 84 , 85 ]. To better understand the mechanism of nucleation and the role of nucleating agents in the nucleation process, it is necessary to follow the process from the formation of the first nuclei, which play a role as a precursor for crystallization, until the complete material crystallization.…”

Section: Examples Of Using the Xafs Technique To Study The Atomic mentioning

confidence: 99%

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Mastelaro

Zanotto

2018

Materials

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X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses.

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Section: Examples Of Using the Xafs Technique To Study The Atomic mentioning

confidence: 99%

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Mastelaro

Zanotto

2018

Materials

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“…1 They are generally much stronger than the precursor glass and are used in many domestic and high-tech applications, such as electrical insulators, hard drive substrates, telescope mirrors, cooktop plates, construction and architecture-as synthetic marble or granite, dental prostheses, or as bioactive materials to replace or regenerate human bones and teeth. [1][2][3] The traditional technique used to produce GCs consists of melting and vitrification, forming a desired glass article of a certain shape, and subjecting it to thermal treatment to induce crystal nucleation and growth inside the piece. In this stage, it is very important to induce copious internal nucleation and crystallization to form a rigid backbone that precludes sagging and deformation of the article (that still contains a significant fraction of glass phase).…”

Section: Introductionmentioning

confidence: 99%

Residual stress effect on the fracture toughness of lithium disilicate glass‐ceramics

et al. 2019

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In glass‐ceramics (GCs), on cooling from the crystallization temperature, internal residual stresses are generated due to the difference between the thermal expansion coefficient (TEC) of the crystal phase(s) and the residual glass. These stresses could degrade or promote their mechanical properties. In this work, we varied the magnitude of the residual stresses in lithium silicate GCs by designing their microstructures. The level of internal stresses was measured using (Synchrotron) X‐ray diffraction. The effects of anisotropy of thermal expansion, crystal shape, and intensity of the residual stresses were analyzed and compared using theoretical models. We extended the Hsueh‐Becher model to include the thermal expansion anisotropy of the orthorhombic lithium disilicate (LS2) crystals. We found that the average residual stresses within the LS2 crystals are compressive or null (−100 to ~0) and highly anisotropic. Most importantly, within the limits of this study, we found no evidence for the influence of (compressive or null) residual stresses on the fracture toughness of the studied GCs. Within the crystal size range from 1 to 5 μm, a highly crystallized volume fraction coupled to relatively large crystals (5 μm) of high elastic modulus improved the glass‐ceramic fracture toughness. This result can guide the microstructural design of novel tough GCs.

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“…It is well known that the crystallization of glass modifies the properties of the starting material. In many instances, these modifications improve glass properties or generate new ones, resulting in a great interest in studying the crystallization from fundamental and technological points of view . Especially, in the design of new oxyfluoride materials for the mentioned applications, it is necessary to choose the adequate components in order to obtain the desired improvements .…”

Section: Introductionmentioning

confidence: 99%

Structural analysis of oxyfluoride borate glass and BaF₂ crystallization from phase separation

Chialanza¹,

Schneider

Keuchkerian³

et al. 2020

J Am Ceram Soc

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Oxyfluoride glass and glass‐ceramics are being studied due to the possibility of their utilization in many applications, such as thermoluminescent dosimeters, optical fibers, fluorescent concentrators, and temperature sensors. In order to improve the properties of glass, they are often crystallized. For this crystallization to be effective, knowledge and control of the structure of the starting material is required. Much work was done on silicate glass; however, a great interest exists in obtaining these kinds of materials in other matrices such as germanates, phosphates, and borates. Here, we present a structural study of some oxyfluoride borate glass with different concentrations of PbF2 by means of Nuclear Magnetic Resonance (NMR), Raman, and Fourier Transform Infrared (FTIR) spectroscopies. We also analyzed glass‐crystallization using Differential Scanning Calorimetry (DSC). The crystallization study was complemented with the use of Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED), for the purpose of identifying possible mechanisms of crystallization. Our results indicate, from the structural point of view, that the glass present groups with one or two BO4 species, such as diborate or pentaborate. The small variation in the BO4 fraction with the increase in PbF2 concentration would be an indication of the formation of F−BO3/2 species. Oxyfluoride borate glass containing BaO as a cation modifier and 30% PbF2 represents a good starting point for obtaining glass‐ceramics with a narrow size distribution of BaF2 nanocrystals. We also propose that the possible mechanism for oxyfluoride borate glass crystallization started with a separation of phases.

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Glass-ceramics and realization of the unobtainable: Property combinations that push the envelope

Abstract: Abstract

Cited by 59 publications

References 10 publications

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Residual stress effect on the fracture toughness of lithium disilicate glass‐ceramics

Structural analysis of oxyfluoride borate glass and BaF₂ crystallization from phase separation

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Glass-ceramics and realization of the unobtainable: Property combinations that push the envelope

Abstract: Abstract

Cited by 59 publications

References 10 publications

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Residual stress effect on the fracture toughness of lithium disilicate glass‐ceramics

Structural analysis of oxyfluoride borate glass and BaF2 crystallization from phase separation

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Structural analysis of oxyfluoride borate glass and BaF₂ crystallization from phase separation