scholarly journals Thermal Expansion and Other Properties of Sodium Chloride

1965 ◽  
Vol 18 (3) ◽  
pp. 205 ◽  
Author(s):  
DGM Powell ◽  
GC Fletcher
Keyword(s):  
Thermal Expansion ◽  
Sodium Chloride ◽  
Melting Point ◽  
Equation Of State ◽  
Reasonable Agreement ◽  
Room Temperature ◽  
Previous Calculation ◽  
Specific Heats ◽  
Comparison With Experiment ◽  
Rigid Ion Model

A previous calculation by one of the authors of the equation of state of an anharmonic rigid-ion model of sodium chloride has been corrected. The results are valid above room temperature and reasonable agreement with experiment is obtained to within about 200 0 of the melting point. Comparison with experiment is also made for specific heats C v ' Cp and compressibilities I<T' I<s'

Influence of Nitride on Sinterability of the Composite of Lithium Aluminum Silicate and Silicon Carbide

2006 ◽  
Vol 317-318 ◽  
pp. 177-180 ◽  
Author(s):  
Mabito Iguchi ◽  
Motohiro Umezu ◽  
Masako Kataoka ◽  
Hiroaki Nakamura ◽  
Mamoru Ishii
Keyword(s):  
Silicon Carbide ◽  
Thermal Expansion ◽  
Melting Point ◽  
Liquid Phase ◽  
Room Temperature ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Sintering Process ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Ceramics with zero thermal expansion coefficients at room temperature (293K) were investigated. We found the thermal expansion coefficient was controlled by a compounding ratio of lithium aluminum silicate (LAS) and silicon carbide (SiC), which have negative and positive thermal expansion coefficients respectively. Although it was difficult to densify the composite of the LAS and SiC (LAS/SiC) in the sintering process, an addition of nitride improved the sinterability of the LAS/SiC. In order to examine the effect of the nitride additive, at first, the melting point of the LAS with silicon nitride (Si3N4) or aluminum nitride was measured by TG-DTA. The melting point of the LAS decreased with existence of nitride. It is believed that the densification of the LAS/SiC was promoted by the nitride, because the nitride causes the LAS/SiC to form a liquid phase, thereby decreasing the melting point. Next, the lattice constant of the LAS with Si3N4 was measured by XRD and it was verified that the a-axis was longer and the c-axis was shorter than those of the LAS without additive. It is supposed that this phenomenon is due to the substitution of nitrogen for oxygen in the LAS lattice, and the decrease of the melting point of the LAS with nitride seems to be influenced by this substitution of nitrogen.

scholarly journals Thermodynamic Properties of La1-xSmxCoO3

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Rasna Thakur ◽  
N. K. Gaur
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Specific Heats ◽  
Lattice Specific Heat ◽  
Lattice Distortions ◽  
First Time ◽  
Rigid Ion Model

We have investigated the bulk modulus and thermal properties of La1-xSmxCoO3 (0≤x≤0.2) at temperatures 1 K≤T≤300 K probably for the first time by incorporating the effect of lattice distortions using the modified rigid ion model (MRIM). The calculated specific heat, thermal expansion, bulk modulus, and other thermal properties reproduce well with the available experimental data, implying that MRIM represents properly the nature of the pure and doped cobaltate. The specific heats are found to increase with temperature and decrease with concentration (x) for the present. The increase in Debye temperature (θD) indicates an anomalous softening of the lattice specific heat because increase in T3-term in the specific heat occurs with the decrease of concentration (x).

scholarly journals The thermal expansion of bismuth by X-ray measurements

1934 ◽  
Vol 143 (849) ◽  
pp. 465-472 ◽  
Keyword(s):  
Thermal Expansion ◽  
Melting Point ◽  
Single Crystals ◽  
Room Temperature ◽  
The Other ◽  
Optical Methods ◽  
Lattice Expansion ◽  
X Ray ◽  
Expansion Curve ◽  
Methods Of Measurement

X-ray measurements recently carried out by the author on the lattice expansion of silver and quartz showed that the coefficients of thermal expansion, over the ranges investigated, are the same as those observed for the specimen as a whole using optical methods. Goetz and Hergenrother, on the other hand, from X-ray measurements on the coefficients of thermal expansion of single crystals of bismuth, claimed to have found a large difference between values obtained by the two methods of measurement. A possible explanatiion of this that their accuracy is not sufficient to establish definitely the deviation of the X-ray measurements from the optical expansion curve. The author has since made X-ray measurements on the expansion of the bismuth lattice from room temperature to just below the melting point, and finds no evidence of such a discrepancy as Goetz and Hergenrother record.

scholarly journals Anharmonicity and the Thermal Expansion of Solids

1961 ◽  
Vol 14 (3) ◽  
pp. 420 ◽  
Author(s):  
GC Fletcher
Keyword(s):  
Thermal Expansion ◽  
Perturbation Theory ◽  
Sodium Chloride ◽  
Specific Heat ◽  
Series Expansion ◽  
Previous Calculation ◽  
Crystal Potential ◽  
The Poor ◽  
Poor Convergence

Using many-particle perturbation theory an attempt has been made to improve the author's previous calculation of the thermal expansion of sodium chloride and to assess the effect of including anharmonic terms in the crystal potential. The results are disappointing; agreement with experiment is poor except at low and moderate temperatures. One reason for this is the poor convergence of a method based on the series expansion of the crystal potential in terms of particle displacements, 8 point further. illustrated by calculations of specific heat and compressibility.

The thermal expansion and high temperature transformation of SnS and SnSe*

1979 ◽  
Vol 149 (1-2) ◽  
Author(s):  
Heribert Wiedemeier ◽  
Frank J. Csillag
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Melting Point ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Orthorhombic Modification ◽  
Temperature Transformation ◽  
Increasing Temperature

AbstractThe thermal expansion of SnS and SnSe has been studied above room temperature up to the melting point of 1163 ± 5K and 1135 ± 5K, respectively, by X-ray diffraction techniques using a 190 mm Unicam high temperature camera. The changes of the lattice parameters indicate that the atomic positions in the (010) plane approach a square planar arrangement with increasing temperature. The transformation of SnS and SnSe from orthorhombic to a pseudotetragonal orthorhombic modification with

scholarly journals On the equation of state for solids

1944 ◽  
Vol 183 (992) ◽  
pp. 87-110 ◽  
Keyword(s):  
High Pressure ◽  
Thermal Expansion ◽  
Melting Point ◽  
Equation Of State ◽  
Potential Energy ◽  
Mechanical Instability ◽  
Crystal Lattices ◽  
Cubic Crystal ◽  
Sublimation Energy ◽  
Very High

The problem of the thermodynamics of crystal lattices has been treated by rigorous methods recently in a series of papers by Born and collaborators. In particular, Bradburn succeeded in deriving the equation of state for a solid cubic crystal, consisting of identical atoms, under the assumption that the mutual potential energy of a pair of atoms satisfies a law of the form ɸ = — ar -m + br -n . In the present paper a method is developed which makes it possible to determine the exponents m and n in the force law for a given element from measurements of the sublimation energy, the compressibility, the thermal expansion coefficient, and the dependence of these quantities on pressure and temperature. The method is applied to a large number of elements, and it is shown that the compression and the thermal expansion of these substances, as predicted by the theory, are in satisfactory agreement with the measured values of these quantities up to very high pressure and up to temperatures near the melting-point. The question whether melting is caused by the mechanical instability of the lattice is also investigated, and a certain rule connecting the two phenomena is found which is closely related to Lindemann’s law.

scholarly journals The Thermal Expansion of Solids

1959 ◽  
Vol 12 (3) ◽  
pp. 237 ◽  
Author(s):  
GC Fletcher
Keyword(s):  
Thermal Expansion ◽  
Sodium Chloride ◽  
Equation Of State ◽  
Specific Heat ◽  
High Temperatures ◽  
Isothermal Compressibility ◽  
Constant Volume ◽  
Normal Vibrations ◽  
Ionic Solid ◽  
Theory And Experiment

From the theory of normal vibrations of a lattice, a practical means of obtaining the equation of state of an ionic solid is developed from which the thermal expansion can be derived. Using previous work by Kellermann, application is made to the case of sodium chloride and the results compared with experiment. Possible reasons for the discrepancy between theory and experiment, which is very large at 'high temperatures, are discussed. The variation with temperature of the specific heat at constant volume and the isothermal compressibility are also investigated.

High temperature dielectric constant of KI

1969 ◽  
Vol 47 (9) ◽  
pp. 969-973 ◽  
Author(s):  
Suresh Chandra
Keyword(s):  
Dielectric Constant ◽  
Thermal Expansion ◽  
High Temperature ◽  
Melting Point ◽  
Thermal Expansion Coefficient ◽  
Standing Wave ◽  
Expansion Coefficient ◽  
Room Temperature ◽  
Polarization Effects ◽  
Complex Polarization

The dielectric constant of KI crystal has been measured at 23.6 GHz from room temperature to near the melting point. A K-band microwave standing wave ratio technique was used for this purpose to avoid complex polarization effects. It was found that the dielectric constant of KI increases more rapidly than for KCl and KBr, presumably due to its larger thermal expansion coefficient at high temperatures.

Influence of vacancies on the thermal expansion of lead near the melting point

Physica ◽  
1957 ◽  
Vol 23 (6-10) ◽  
pp. 622-624 ◽  
Author(s):  
J. van Duijn ◽  
J. van Galen
Keyword(s):  
Thermal Expansion ◽  
Melting Point
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