Nucleation and crystal growth in commercial LAS compositions

Guedes, M.; Ferro, A.C.; Ferreira, J.M.F.

doi:10.1016/s0955-2219(00)00333-2

Cited by 95 publications

(40 citation statements)

References 11 publications

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“…Nucleation agents, either single or a combination of several, including TiO2, ZrO2, P2O5, and Ta2O5 have been used to produce a bulk nucleation owing to a liquid-liquid phase separation (Barbieri et al, 1997b;Guedes et al, 2001;Wurth et al, 2009;Ananthanarayanan et al, 2010;Li et al, 2010;Nemati et al, 2010;Höche et al, 2011;Höche et al, 2012;Montedo et al, 2012;Chavoutier et al, 2014;Kleebusch et al, 2016;Soares and Zanotto, 2016). Although minor in concentration, nucleation agents are critical to the final microstructure and properties of glass-ceramics.…”

Section: Discussionmentioning

confidence: 99%

Crystallization, Microstructure, and Viscosity Evolutions in Lithium Aluminosilicate Glass-Ceramics

Fu¹,

Wheaton²,

Geisinger³

et al. 2016

Front. Mater.

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Lithium aluminosilicate glass-ceramics have found widespread commercial success in areas such as consumer products, telescope mirrors, fireplace windows, etc. However, there is still much to learn regarding the fundamental mechanisms of crystallization, especially related to the evolution of viscosity as a function of the crystallization (ceramming) process. In this study, the impact of phase assemblage and microstructure on the viscosity was investigated using high-temperature X-ray diffraction (HTXRD), beam bending viscometry (BBV), and transmission electron microscopy (TEM). Results from this study provide a first direct observation of viscosity evolution as a function of ceramming time and temperature. Sharp viscosity increases due to phase separation, nucleation, and phase transformation are noticed through BBV measurement. A nearnet shape ceramming can be achieved in TiO2-containing compositions by keeping the glass at a high viscosity (>10 9 Pa s) throughout the whole thermal treatment.

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Section: Discussionmentioning

confidence: 99%

Crystallization, Microstructure, and Viscosity Evolutions in Lithium Aluminosilicate Glass-Ceramics

Fu¹,

Wheaton²,

Geisinger³

et al. 2016

Front. Mater.

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“…The variation in the shape and peak positions of the TL signal could be mainly a consequence of the strong thermal annealing given to the samples. During the annealing treatment there are different processes that simultaneously can occur in the material, (i) reversible phase transition from beta-quartz structure (hexagonal symmetry) to keatite (tetragonal symmetry) [1] or phase transformations [13]; (ii) consecutive breaking linking of bonds where thermal preheating reduces the adsorbed water content and the hydroxyl groups, [18]. One can distinguish this TL changes that are in agreement with the observed modifications in the X-ray diffractograms that show variations in the structure of the patterns.…”

Section: Thermoluminescence Emissionmentioning

confidence: 99%

“…turbine engine heat exchangers, mirror substrates for telescopes, cookware, etc.) [1]. However, the optical properties in general and the luminescence emission in particular of different members of LAS series have been scarcely investigated.…”

Section: Introductionmentioning

confidence: 99%

Blue thermoluminescence emission of annealed lithium rich aluminosilicates

et al. 2010

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The blue thermoluminescence (TL) emission of different thermally annealed (i) β-eucryptite (LiAlSiO 4 ), (ii) virgilite-petalite (LiAlSi 5 O 12 ) and (iii) virgilite-petalite-bikitaite (LiAlSi 10 O 22 ) mixed crystals have been studied. The observed changes in the TL glow curves could be linked to simultaneous processes taking place in the lithium aluminosilicate lattice structure (phase transitions, consecutive breaking linking of bonds, alkali self-diffusion, redox reactions, etc). The stability of the TL signal after four months of storage performed at RT under red light, shows big differences between annealed (12 hours at 1200 o C) and non-annealed samples. The fading process in non-annealed samples can be fitted to a first-order decay mathematical expression; however preheated samples could not be reasonably fitted due to the highly dispersion detected. The changes observed in the X-ray diffractograms are in the intensity of the peaks that denote modifications in the degree of crystallinity and, in addition, there are some differences in the appeareance of new peaks that could suppose new phases (e.g. β-spodumene).

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“…The peculiar properties of these glass-ceramics are due to the framework structure of aluminosilicate tetrahedra which are the main crystalline phases. This crystal structure has very low bulk thermal expansion and also possesses low thermal expansion with consequent benefit of exceptional thermal stability and thermal shock resistance [2]. Glass-ceramics consisting of fine crystals of ␤-spodumene (Li 2 O·Al 2 O 3 ·4SiO 2 , LAS 4 ) and ␤-eucryptite (Li 2 O·Al 2 O 3 ·2SiO 2 , LAS 2 ) are of particular importance from a technological standpoint in that it encompasses such properties [3].…”

Section: Introductionmentioning

confidence: 99%