The Thermal Expansion of Solid State BaFe12O19 and Flux Ba0.8Pb0.2Fe12O19 Pellets

2017 ◽  
Vol 265 ◽  
pp. 906-910 ◽  
Author(s):  
S.A. Gudkova ◽  
A.S. Chernukha ◽  
D.A. Vinnik
Keyword(s):  
Thermal Expansion ◽  
Solid State ◽  
Curie Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Barium Hexaferrite ◽  
Dsc Measurements ◽  
Differential Scanning Colorimetry ◽  
Good Agreement

Solid state sintered pellets of barium hexaferrite were performed. The Curie temperature of BaFe12O19 pellets were measured with differential scanning colorimetry (DSC). The coefficient of thermal expansion (CTE) of pellets was defined above and below the Curie temperature. The Curie temperature calculated basedon the dilatometry is are in good agreement with the DSC measurements.

Development of a Continuous Cooling Transformation Diagram for an Al-Zn-Mg Alloy Using Dilatometry

2015 ◽  
Vol 828-829 ◽  
pp. 188-193 ◽  
Author(s):  
Manoj Kumar ◽  
Nigel Ross ◽  
Iris Baumgartner
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Rate Of Change ◽  
Precipitation Reaction ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Transformation Diagram ◽  
Multiple Devices ◽  
Continuous Cooling Transformation Diagram ◽  
Good Agreement

To develop CCT diagram using DSC requires the use of multiple devices in order to measure across the range of cooling rates required to develop the diagram. In the current work one dilatometer is used to characterize the precipitation reactions of the AA7020 alloy. Precipitation and dissolution reactions resulted in changes in the rate of change in the coefficient of thermal expansion. This was used to determine the start and finish temperatures of the MgZn2 precipitation reaction and produce the CCT diagram. Good agreement was found between the results of this technique and DSC results from the literature.

SIZE AND TEMPERATURE EFFECT ON THERMAL EXPANSION COEFFICIENT AND LATTICE PARAMETER OF NANOMATERIALS

2013 ◽  
Vol 27 (25) ◽  
pp. 1350180 ◽  
Author(s):  
RAGHUVESH KUMAR ◽  
GEETA SHARMA ◽  
MUNISH KUMAR
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Temperature Dependence ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Size Dependence ◽  
Coefficient Of Thermal Expansion ◽  
Lattice Parameter ◽  
Model Predictions ◽  
Good Agreement

A simple theoretical model is developed to study the effect of size and temperature on the coefficient of thermal expansion and lattice parameter of nanomaterials. We have studied the size dependence of thermal expansion coefficient of Pb , Ag and Zn in different shape viz. spherical, nanowire and nanofilm. A good agreement between theory and available experimental data confirmed the model predictions. We have used these results to study the temperature dependence of lattice parameter for different size and also included the results of bulk materials. The temperature dependence of lattice parameter of Zn nanowire and Ag nanowire are found to present a good agreement with the experimental data. We have also computed the temperature and size dependence of lattice parameter of Se and Pb for different shape viz. spherical, nanowire and nanofilm. The results are discussed in the light of recent research on nanomaterials.

scholarly journals A Novel Method for Determining the Curie Temperature of Ferroelectric Films

1993 ◽  
Vol 310 ◽  
Author(s):  
Chi Kong Kwok ◽  
Seshu B. Desu
Keyword(s):  
Thermal Expansion ◽  
Curie Temperature ◽  
Elastic Constants ◽  
Ferroelectric Phase ◽  
Film Stress ◽  
Ferroelectric Films ◽  
Stress Changes ◽  
Novel Method ◽  
Curie Temperatures ◽  
Good Agreement

AbstractA novel technique to measure the Curie temperature of ferroelectric thin films has been developed. The method is based on identifying changes in slope of film stress vs temperature plot. At the Curie temperature, ferroelectric films undergo a phase transition from ferroelectric phase to paraelectric phase. Due to this phase transformation, physical properties of films such as elastic constants and coefficients of thermal expansion also change at the Curie temperature. Consequently, at this temperature the temperature coefficient of film stress changes since it is related to elastic constants and thermal expansion coefficient. Thus, by measuring the film stress as a function of temperature, the Curie temperature can be determined. The Curie temperatures measured by this method are in good agreement with the literature values. Small discrepancies that were observed can be attributed to the intrinsic stresses present in the films.

scholarly journals Coefficient of Thermal Expansion of Single-Wall Carbon Nanotube Reinforced Nanocomposites

2021 ◽  
Vol 5 (1) ◽  
pp. 26
Author(s):  
Chensong Dong
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Carbon Nanotube ◽  
Interfacial Adhesion ◽  
Coefficient Of Thermal Expansion ◽  
Single Wall Carbon Nanotube ◽  
Single Wall Carbon ◽  
The Matrix ◽  
Adhesion Factor ◽  
Good Agreement

A study on the coefficient of thermal expansion (CTE) of single-wall carbon nanotube (SWCNT)-reinforced nanocomposites is presented in this paper. An interfacial adhesion factor (IAF) is introduced for the purpose of modelling the adhesion between SWCNTs and the matrix. The effective CTE and modulus of SWCNTs are derived using the IAF, and the effective CTE of the nanocomposite is derived by the Mori–Tanaka method. The developed model is validated against experimental data and good agreement is found.

scholarly journals TO THE PROBLEM OF DETERMINING THE COEFFICIENT OF THERMAL EXPANSION OF MATERIALS

2020 ◽  
pp. 284-292
Author(s):  
Денис Васильевич Пьянзин ◽  
Николай Александрович Панькин ◽  
Александр Николаевич Чалдышкин ◽  
Николай Иванович Чистяков
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Computer Simulation ◽  
Thermal Expansion ◽  
Software Package ◽  
Coefficient Of Thermal Expansion ◽  
Metallic Materials ◽  
Ansys Software ◽  
Simulation Results ◽  
Good Agreement

Проведено экспериментальное исследование и компьютерное моделирование в программном комплексе ANSYS термического воздействия на металлический материал. Отмечается уменьшение значений коэффициента теплового расширения при увеличении скорости нагрева образца. Показано, что данное поведение обусловлено наличием градиента температур между его центральной и поверхностью частями. Отмечается хорошее согласие результатов компьютерного моделирования с соответствующими экспериментальными данными. Значения коэффициента теплового расширения близки к истинным, которые были определены при малых скоростях нагрева/охлаждения или при длительной выдержке образца при конечной и начальной температурах. Результаты моделирования в ANSYS могут быть использованы при интерпретации и прогнозировании тепловых свойств металлических материалов. An experimental study and computer modeling in the ANSYS software package of the thermal effect on a metal material was carried out. A decrease in the values of the coefficient of the thermal expansion is noted with an increase in the heating rate of the sample. It is shown that this behavior is due to the presence of the temperature gradient between its central and surface parts. Good agreement of the results of computer simulation with the corresponding experimental data is found. The values of the coefficient of thermal expansion are close to true ones determined at low heating / cooling rates or with long exposure of the sample at the final and initial temperatures. The simulation results in ANSYS can be used to interpret and predict thermal properties of metallic materials.

Mechano-thermally Activated Solid-state Synthesis of Li4Ti5O12 Spinel from Li2CO3-TiO2 Mixtures

2010 ◽  
Vol 65 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Vittorio Berbenni ◽  
Chiara Milanese ◽  
Giovanna Bruni ◽  
Amedeo Marini
Keyword(s):  
Solid State ◽  
Gas Adsorption ◽  
High Energy ◽  
Solid State Synthesis ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Thermally Activated ◽  
High Energy Milling ◽  
Dsc Measurements ◽  
Good Agreement

Simultaneous TG/DSC measurements performed on mixtures 2Li2CO3-5TiO2 (anatase) subjected to high-energy milling showed that both the temperature and the enthalpy of Li2CO3 decomposition are much lower than in the case of TG/DSC runs performed on a sample of a physical mixture. On the basis of the thermoanalytical evidence a solid-state synthesis of the spinel compound Li4Ti5O12 has been proposed that combines mechanical (by high-energy milling) and thermal activation (8 h annealing at 973 K): the obtained compound shows a lattice constant in very good agreement with that expected for the pure phase Li1+xTi2−xO4 (x = 0.333). The molar heat capacity of Li4Ti5O12 has been determined in the temperature range 323 - 633 K by quasi-isothermal Modulated Differential Scanning Calorimetry (MDSC). The specific surface area of Li4Ti5O12 has been determined by gas adsorption

Powder Diffraction and Dilatometric Study of SrFe12O19

2019 ◽  
Vol 946 ◽  
pp. 336-340
Author(s):  
Svetlana A. Gudkova ◽  
Danil A. Uchaev ◽  
D.A. Vinnik
Keyword(s):  
Thermal Expansion ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Coefficient Of Thermal Expansion ◽  
Strontium Hexaferrite ◽  
X Ray Diffraction ◽  
Spontaneous Crystallization ◽  
X Ray ◽  
Cell Parameters ◽  
Good Agreement

Strontium hexaferrite is a well-known material, due to its application in microelectronics. This paper is devoted to strontium hexaferrite single crystals, obtained by the spontaneous crystallization technique with sodium based flux. SrFe12O19 crystals were grounded, pressed to the tablets, and crystals cell parameters were measured by thermal X-ray diffraction technique. Coefficient of thermal expansion calculated from the X-ray thermal diffraction data is in a good agreement with dilatometric measurements.

Thermal Expansion of Lithium Sulphate

1968 ◽  
Vol 23 (9) ◽  
pp. 1259-1261 ◽  
Author(s):  
Bengt Augustsson ◽  
Alf Ekhed
Keyword(s):  
Thermal Expansion ◽  
Monoclinic Phase ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Temperature Curve ◽  
Cubic Phase ◽  
Linear Coefficient ◽  
Cubic Phases ◽  
Lithium Sulphate ◽  
Good Agreement

The coefficient of linear thermal expansion has been measured for polycrystalline Li2SO4. Between 200 and 550 °C (monoclinic phase) the average linear coefficient of thermal expansion was determined to (22 ± 1) x10-6 degr.-1, and for the range 600—750 °C (cubic phase) the coefficient (43 ±3)x 10-6 degr.-1 was obtained. The quoted errors are standard deviations.The volume change at the transition between the monoclinic and cubic phases was found to be 2.2 cm3/mole, which is in good agreement with Pistorius’ estimation from the pressure-temperature curve of this transition.

A Free Energy Perturbation Approach to Estimate the Intrinsic Solubilities of Drug-like Small Molecules

2019 ◽  
Author(s):  
Sayan Mondal ◽  
Gary Tresadern ◽  
Jeremy Greenwood ◽  
Byungchan Kim ◽  
Joe Kaus ◽  
...  
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Three Dimensional ◽  
Aqueous Solubility ◽  
Computational Approach ◽  
Free Energy Perturbation ◽  
Perturbation Approach ◽  
Energy Perturbation ◽  
State Form ◽  
Good Agreement

<p>Optimizing the solubility of small molecules is important in a wide variety of contexts, including in drug discovery where the optimization of aqueous solubility is often crucial to achieve oral bioavailability. In such a context, solubility optimization cannot be successfully pursued by indiscriminate increases in polarity, which would likely reduce permeability and potency. Moreover, increasing polarity may not even improve solubility itself in many cases, if it stabilizes the solid-state form. Here we present a novel physics-based approach to predict the solubility of small molecules, that takes into account three-dimensional solid-state characteristics in addition to polarity. The calculated solubilities are in good agreement with experimental solubilities taken both from the literature as well as from several active pharmaceutical discovery projects. This computational approach enables strategies to optimize solubility by disrupting the three-dimensional solid-state packing of novel chemical matter, illustrated here for an active medicinal chemistry campaign.</p>

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