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Journal ArticleDOI

SiO2–Al2O3–CaO glass-ceramics: Effects of CaF2 on crystallization, microstructure and properties

01 Jan 2013-Ceramics International (Elsevier)-Vol. 39, Iss: 1, pp 571-578
TL;DR: In this paper, the effects of fluorine content on the nucleation and crystallization behavior of SiO 2 -Al 2 O 3 -CaO glass ceramics system have been investigated.
About: This article is published in Ceramics International.The article was published on 2013-01-01. It has received 76 citations till now. The article focuses on the topics: Crystallization & Differential thermal analysis.
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TL;DR: This article is an attempt to provide state of the art of the sol-gel and melt quenched bioactive bioglasses for tissue regeneration and the effect of these fabrication techniques on the porosity, pore-volume, mechanical properties, cytocompatibilty and especially apatite layer formation on the surface of bioglass is analyzed in detail.
Abstract: Biomaterial development is currently the most active research area in the field of biomedical engineering. The bioglasses possess immense potential for being the ideal biomaterials due to their high adaptiveness to the biological environment as well as tunable properties. Bioglasses like 45S5 has shown great clinical success over the past 10 years. The bioglasses like 45S5 were prepared using melt-quenching techniques but recently porous bioactive glasses have been derived through sol-gel process. The synthesis route exhibits marked effect on the specific surface area, as well as degradability of the material. This article is an attempt to provide state of the art of the sol-gel and melt quenched bioactive bioglasses for tissue regeneration. Fabrication routes for bioglasses suitable for bone tissue engineering are highlighted and the effect of these fabrication techniques on the porosity, pore-volume, mechanical properties, cytocompatibilty and especially apatite layer formation on the surface of bioglasses is analyzed in detail. Drug delivery capability of bioglasses is addressed shortly along with the bioactivity of mesoporous glasses. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1248-1275, 2016.

127 citations

Journal ArticleDOI
TL;DR: In this article, the effects of compositional variation, crystallization behavior, crystalline phases and microstructure formed in the SiO23Al2O33CaO (SAC) glass system using various amounts of TiO2 as nucleating agent were investigated by Differential Thermal Analysis (DTA), X-ray powder diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive Xray spectroscopy (EDAX) and Fourier transform infrared spectrography (FTIR) techniques.

68 citations

Journal ArticleDOI
M. Kemere1, J. Sperga1, Uldis Rogulis1, Guna Krieke1, J. Grube1 
TL;DR: In this article, the most promising doping combinations for white light luminophores within the research are europium-dysprosium and europarbium-terbium, which allow obtaining white light both in glasses and glass-ceramics under 355 and 450 nm excitation.

48 citations

Journal ArticleDOI
TL;DR: In this paper, the epitaxial growth of the diopside on the spinel particles, which formed during nucleation treatment when fabricating the glass-ceramics, facilitated the heterogeneous nucleation of diop side on spinel and refined the diops side.
Abstract: CaO-AlO-MgO-SiO (CAMS)-based glass-ceramics were prepared using body crystallization method. Adding CrO into the ceramics not only effectively lowered the crystallization temperature, but also led to significant grain refinement of diopside that crystallized in the CAMS glass-ceramic after crystallization treatment at 900°C for 2 hours. Experimental work verified that the epitaxial growth of the diopside on the spinel particles, which formed during nucleation treatment when fabricating the glass-ceramics, facilitated the heterogeneous nucleation of diopside on the spinel and refined the diopside. In addition, two energetically favored crystallographic orientation relationships between the epitaxial growth diopside and spinel were experimentally observed. They are [1-12]spinel//[001],//(11-1)spinel//(200) and [1-12]spinel]//[101], (311)//(131-)diopside. These two novel results can be potentially used to develop new glass-ceramic materials with improved performance.

47 citations

Journal ArticleDOI
TL;DR: The efforts to analyze the relationship between the existing processes and attempts to establish a comprehensive technology to treat tungsten slag are focused on and areas for future research are suggested.

44 citations

References
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TL;DR: In this paper, the theory of phase change is developed with the experimentally supported assumptions that the new phase is nucleated by germ nuclei which already exist in the old phase, and whose number can be altered by previous treatment.
Abstract: The theory of the kinetics of phase change is developed with the experimentally supported assumptions that the new phase is nucleated by germ nuclei which already exist in the old phase, and whose number can be altered by previous treatment. The density of germ nuclei diminishes through activation of some of them to become growth nuclei for grains of the new phase, and ingestion of others by these growing grains. The quantitative relations between the density of germ nuclei, growth nuclei, and transformed volume are derived and expressed in terms of a characteristic time scale for any given substance and process. The geometry and kinetics of a crystal aggregate are studied from this point of view, and it is shown that there is strong evidence of the existence, for any given substance, of an isokinetic range of temperatures and concentrations in which the characteristic kinetics of phase change remains the same. The determination of phase reaction kinetics is shown to depend upon the solution of a functional equation of a certain type. Some of the general properties of temperature‐time and transformation‐time curves, respectively, are described and explained.

9,458 citations

Journal ArticleDOI
TL;DR: In this article, the temperature at which the maximum deflection is observed varies with heating rate for certain types of reactions, and an expression can be derived relating this variation with the kinetics of the reaction.
Abstract: In differential thermal analysis, the temperature at which the maximum deflection is observed varies with heating rate for certain types of reactions. An expression can be derived relating this variation with the kinetics of the reaction. By making a number of differential thermal patterns at different heating rates, the kinetic constants can be obtained directly from the differential thermal data. Measurements of the variation of peak temperature with heating rate have been made for several minerals of the kaolin group, the values of the kinetic constants determined, and these values compared with corresponding values obtained for both the same samples and similar material by conventional isothermal techniques. Some factors affecting the results are discussed. The method of differential thermal analysis (DTA) has been universally accepted by mineralogical laboratories as a rapid and convenient means for recording the thermal effects that occur as a sample is heated. Changes in heat content of the active sample are indicated by deflections shown by a line representing the differential temperature. It is conventional to represent an endothermic effect by a negative deflection and an exothermic effect by a positive deflection. The deflections, whether positive or negative, are called peaks.

3,138 citations

Journal ArticleDOI
J. A. Augis1, J. E. Bennett1
TL;DR: In this article, an extension of the Kissinger method was proposed for the analysis of the transformation kinetics of the metastable equiatomic tin-nickel alloy with differential thermal analysis (DTA).
Abstract: Several isothermal experiments are generally needed to determine the parameters of the Avrami equation which describe most of the heterogeneous solid state reactions. Differential scanning calorimeters are suitable for such experiments. While most differential thermal analysis (DTA) apparatus cover a wider temperature range than DSC apparatus they cannot be used to perform isothermal determinations. However, Kissinger has already shown how activation energy and frequency factor can be calculated from DTA experiments for the case of homogeneous reactions following first order kinetics. We derive in this paper an extension of the Kissinger method and show its applicability to heterogeneous reactions described by an Avrami expression. The new method will allow the study of the kinetics of metallic reactions at the higher temperature range obtainable with DTA. The transformation kinetics of the metastable equiatomic tin-nickel alloy are given as an example.

1,067 citations