scholarly journals Crystallization kinetics of K2O·TiO2·3GeO2 glass studied by DTA

2008 ◽  
Vol 40 (3) ◽  
pp. 333-338 ◽  
Author(s):  
S. Grujic ◽  
N. Blagojevic ◽  
M. Tosic ◽  
V. Zivanovic ◽  
J. Nikolic
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Samples ◽  
Kinetics Of

Crystallization kinetics of K2O?TiO2?3GeO2 glass was investigated by differential thermal analysis (DTA). Experiments were performed on powder samples with a particle size < 0.037 mm. The glass samples were heated at different rates in the temperature range 20-750?C. The kinetic parameters, activation energy for the crystallization process, Ec and Avrami exponent, n were calculated. Powder X-ray diffraction analysis (XRD) of crystallized glass reveals the presence of crystalline K2O?TiO2?3GeO2 indicating polymorphic crystallization with interface controlled crystal growth.

Thermal Stability vs. Crystallization of the Lithiumsilicate Glasses with Addition Zirconium Dioxide and Titanium Dioxide

2008 ◽  
Vol 39-40 ◽  
pp. 399-401
Author(s):  
Viliam Pavlík ◽  
Eugen Jóna ◽  
Martina Sapietová ◽  
Soňa Šnircová
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Analysis ◽  
Titanium Dioxide ◽  
Differential Thermal Analysis ◽  
Structural Analysis ◽  
Zirconium Dioxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Relationship

The glasses with composition of Li2O . 2 SiO2 . n ZrO2 . n TiO2 (where n = 0; 0.015; 0.031; 0.050; 0.075; 0.1; 0.15; 0.2) were prepared and the relationship between structural and selected parameters of thermal stability vs. crystallization has been studied by differential thermal analysis. Structural analysis was provided by X–ray diffraction. The order of thermal stability vs. crystallization representing of activation energy of studied glass systems which increase with higher addition both oxides. The same order was obtained from the values of XRD. On the comparison the glasses with zero addition titanium dioxide their activation energy was much higher.

Thermal Analysis and Evolution of Phases during the Synthesis of Cordierite with Kyanite and Talc

2006 ◽  
Vol 509 ◽  
pp. 199-204
Author(s):  
Iván Vernet-Patiño ◽  
Heberto Balmori-Ramírez ◽  
Richard C. Bradt
Keyword(s):  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Phase

Cordierite has been synthesized by heating mixtures of kyanite and talc, using kyanite powders of two different sizes. The reaction is studied by thermogravimetric and differential thermal analysis. Phase changes are followed by X-Ray diffraction of samples fired between 750 °C and 1400 °C. The evolution of the reaction starts with the dehydration of talc at approximately 880 °C. The kyanite decomposes at approximately 1140 °C. The first traces of α-cordierite appear at around 1200 °C. The influence of the kyanite particle size on the kinetics and microstructure is analyzed.

Crystallization Kinetics of Sol-gel-derived (1x)SrBi2Ta2O9–xBi3TiTaO9 Ferroelectric Thin Films

2002 ◽  
Vol 17 (6) ◽  
pp. 1463-1468 ◽  
Author(s):  
Woo-Chul Kwak ◽  
Yun-Mo Sung
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Crystallization Kinetics ◽  
Sol Gel ◽  
Avrami Exponent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isothermal Kinetic Analysis ◽  
Isothermal Kinetic ◽  
Kinetics Of

The crystallization kinetics of Sr0.7Bi2.3Ta2O9 (SBT) and 0.7SrBi2Ta2O9–0.3Bi3TiTaO9 (SBT-BTT) thin films formed by the sol-gel and spin coating techniques were studied. Phase formation and crystal growth are greatly affected by the film composition and crystallization temperature. Isothermal kinetic analysis was performed on the x-ray diffraction results of the thin films heated in the range of 730 to 760 °C at 10 °C intervals. Activation energy and Avrami exponent values were determined for the fluorite-to-Aurivillus phase transformation. A reduction of approximately 51 kJ/mol in activation energy was observed for the SBT-BTT thin films, and an Avrami exponent value of approximately 1.0 was obtained for both the SBT and SBT-BTT. A comparison is made, and the possible crystallization mechanism is discussed.

Crystallization process and magnetic property of Fe81Zr3Nb6B10 alloy

2015 ◽  
Vol 29 (31) ◽  
pp. 1550196 ◽  
Author(s):  
Y. M. Sun ◽  
W. Q. Yu ◽  
D. Long ◽  
Y. Zhang ◽  
Z. Hua
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Magnetic Property ◽  
Differential Thermal Analysis ◽  
Melt Spinning ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray

[Formula: see text] amorphous alloy was prepared by melt-spinning and annealed at various temperatures. The thermal property, microstructure and magnetic property were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The crystallization process of [Formula: see text] alloy is as follow: Amorphous [Formula: see text] residual amorphous [Formula: see text]-[Formula: see text]-[Formula: see text]-[Formula: see text] solid solution. Coercivity [Formula: see text] of [Formula: see text] alloy changes complexly, which abruptly deteriorates at 843 K and then softens with increasing annealing temperature [Formula: see text].

scholarly journals Морфология поверхности и структура плазменных покрытий

2019 ◽  
Vol 89 (2) ◽  
pp. 239
Author(s):  
А.А. Лепешев ◽  
И.В. Карпов ◽  
А.В. Ушаков ◽  
Г.М. Зеер ◽  
В.Г. Демин ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Structural Transformations ◽  
X Ray Diffraction ◽  
Cobalt Alloy ◽  
X Ray ◽  
Plasma Sputtering ◽  
Temperature Heating ◽  
Kinetics Of ◽  
Amorphous Coatings

AbstractSpecific features of the structure formation in rapidly quenched high-cobalt alloy coatings formed by plasma sputtering have been investigated. The structural state of the investigated coatings has been identified by the X-ray diffraction technique. The sequence and kinetics of structural transformations occurring in the specified time-temperature heating regimes have been examined using differential thermal analysis. It has been established that heat generation and crystallization temperature depend on the conditions of formation of bulk amorphous coatings.

Crystallization Kinetics of MgO–Al2O3–SiO2 Transparent Glass–Ceramics

2012 ◽  
Vol 509 ◽  
pp. 230-234 ◽  
Author(s):  
Jin Shu Cheng ◽  
Jing Wang ◽  
Li Ying Tang ◽  
Zhen Lu Deng
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Glass Ceramics ◽  
Crystal Phase ◽  
Spinel Crystal ◽  
X Ray Diffraction ◽  
Isothermal Crystallization Kinetics ◽  
X Ray ◽  
Spinel Mgal2o4 ◽  
Kinetics Of

The non-isothermal crystallization kinetics of the MgO–Al2O3–SiO2 (MAS) glasses were analyzed with the Kissinger equation and the Augis-Bennett equation by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The results showed that two crystal phases of spinel (MgAl2O4) and SiO2 were generated sequentially in the heat treatment process. When the spinel was the only crystal phase, the MAS glass-ceramic was transparent. For glass A (containing one type alkali metal Na2O), the corresponding activation energy was Ep1(A)=325.27kJ/mol, Ep2(A)=364.99kJ/mol; for glass B (containing Na2O and K2O) , the activation energy is Ep1(B)=233.79kJ/mol, Ep2(B)=273.85kJ /mol. The average crystallization index for spinel crystal phase was nA1=1.99, nB1=2.58, By adding K+, which suggested that the spinel crystal phase precipitation have the trend to change from two-dimensional pattern to bulk crystallization.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

Crystallization of Zn-rich and P-rich amorphous Zn3P2 thin films

1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Activation Energy ◽  
Electrical Properties ◽  
Structural Properties ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Conductivity Activation Energy ◽  
X Ray

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.

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