Linear Thermal Expansion Measurements Research Articles

Synthesise and Characterization of Cordierite and Wollastonite Glass-Ceramics Derived from Industrial Wastes and Natural Raw Materials.

Industrial waste is one of the primary sources that harm the environment, and this topic has occupied many scientists on how to take advantage of these wastes or dispose of them and create a clean environment. By-pass cement dust is considered one of the most dangerous industrial wastes due to its fine granular size and its volatilization in the air, which causes severe environmental damage to human and animal health, and this is the reason for choosing the current research point. In this article, eight samples of glass–ceramics were prepared using by-pass cement dust and natural raw materials known as silica sand, magnesite, and kaolin. Then melted by using an electric furnace which was adjusted at a range of temperatures from 1550 to 1600 °C for 2 to 3 h; the samples were cast and were subjected to heat treatment at 1000 °C for 2 h based on the DTA results in order to produce crystalline materials. Various techniques were used to study the synthesized glass–ceramic samples, including differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscope (SEM), and thermal expansion coefficient (CTE). X-ray analysis showed that the phases formed through investigated glass–ceramic samples consisted mainly of β- wollastonite, parawollastonite, diopside, anorthite, and cordierite. It was noticed that β- the wollastonite phase was formed first and then turned into parawollastonite, and also, the anorthite mineral was formed at low temperatures before the formation of the diopside mineral. SEM showed that the formed microstructure turned from a coarse grain texture to a fine-grained texture, by increasing the percentage of cordierite. It also showed that the increase in time at the endothermic temperature significantly affected the crystalline texture by giving a fine-grained crystalline texture. The linear thermal expansion measurements technique used for the studied glass–ceramic samples gives thermal expansion coefficients ranging from 6.2161 × 10−6 to 2.6181 × 10−6 C−1 (in the range of 20–700 °C), and it decreased by increasing cordierite percent.

Magnetoelastic properties in polycrystalline Fe-Pd based ferromagnetic shape memory alloys

Two series of Mn substituted Fe-Pd ferromagnetic shape memory ribbons were studied by X-ray diffraction, calorimetric and thermo-induced strain measurements. Linking the structural, magnetic and thermal expansion analysis on pristine ribbons and those subjected to different subsequent thermal treatments, highlights the role of substitution and of heat treatment of the martensitic transformation (MT). The melt–spinning technique removes the precipitation of undesirable b.c.t. irreversible phase and the addition of Mn, as a third alloying element, promotes the stabilization of the f.c.t. martensite. The linear thermal expansion measurements with and without static magnetic field provide information on the easy magnetization axis in the martensitic structure. Preliminary in vitro cytotoxicity tests generally indicate no toxicity or a tendency towards cell proliferation induced by the tested materials.

Thermal and hygroscopic expansion characteristics of bamboo

The expansion and contraction of bamboo caused by temperature and moisture variations must be evaluated if bamboo is to be utilised as a building material. However, detailed expansion data, especially data in the ascent and descent processes of temperature and moisture are unexplored. The aim of this study is to investigate the expansion characteristics of Phyllostachys edulis (Moso bamboo) in ascent and descent processes of temperature and moisture. The measurement of linear thermal expansion and hygroexpansion of bamboo specimens were conducted with a dilatometer and a micrometer, respectively. The temperature range of the linear thermal expansion measurement was between 23 and 70°C. In the linear moisture expansion measurement, all specimens were measured at various relative humidity (RH) conditions including oven dry, 27, 54, 76 and 95%RH, and water soaking stages. Major findings include: the swell of bamboo specimens increases with RH, whereas the shrinkage of bamboo specimens decreases with RH. The hygroexpansion is much more significant compared with the linear thermal expansion. Both linear thermal expansion and hygroexpansion of the specimens from the longitudinal directions are smaller than those from the radial direction and tangential direction.

Structural, electrical and thermal expansion studies of tri-doped ceria electrolyte materials for IT-SOFCs

Nano crystalline tri-doped ceria Ce1–x(Pr1/3Sm1/3Gd1/3)xO2-δ (x = 0.00, 0.06, 0.12, 0.18, 0.24 and 0.30) solid electrolyte materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) were successfully synthesized by sol-gel auto-combustion method. The X-ray diffraction patterns of prepared compositions confirm the sample formation with a single-phase cubic fluorite structure. Reitveld refinement of all the samples carried out by using Fullprof software. The values of lattice parameter and average crystallite size values were calculated from the XRD patterns and were found to vary from 5.4107 Å to 5.4403 Å and from 18 to 32 nm respectively. Relative densities of all the samples were found above 95% after sintering at 1300 °C for 4 h. Microstructure and elemental composition were studied using scanning electron microscope (SEM) with energy dispersive spectrum (EDS). Evaluation of the concentration of oxygen vacancies of all the samples was carried out using Raman spectroscopy. The electrical properties of tri-doped ceria system were carried out by A.C. impedance spectroscopy in the temperature range from 250 to 600 °C. The investigation on total ionic conductivity was carried out with variation in microstructure and relative oxygen vacancies. It was found that among all the compositions, Ce0.76Pr0.08Sm0.08Gd0.08O2−δ exhibits highest total ionic conductivity and minimum activation energy. The linear thermal expansion measurements revealed moderate linear thermal expansion coefficient for this composition in the temperature range of 30 °C and 1000 °C. Therefore, it is concluded that tri-doped ceria material i.e. Ce0.76Pr0.08Sm0.08Gd0.08O2−δ may possible candidate for use as solid electrolyte in IT-SOFCs.

Magnetocaloric effect and negative thermal expansion in hexagonal Fe doped MnNiGe compounds with a magnetoelastic AFM-FM-like transition

We report a detailed study of two successive first-order transitions, including a martensitic transition (MT) and an antiferromagnetic (AFM)-ferromagnetic (FM)-like transition, in Mn1-xFexNiGe (x = 0, 0.06, 0.11) alloys by X-ray diffraction, differential scanning calorimetry, magnetization and linear thermal expansion measurements. Such an AFM-FM-like transition occurring in the martensitic state has seldom been observed in the M(T) curves. The results of Arrott plot and linear relationship of the critical temperature with M2 provide explicit evidence of its first-order magnetoelastic nature. On the other hand, their performances as magnetocaloric and negative thermal expansion materials were characterized. The isothermal entropy change for a field change of 30 kOe reaches an impressive value of −25.8 J/kg K at 203 K for x = 0.11 compared to the other two samples. It demonstrates that the magneto-responsive ability has been significantly promoted since an appropriate amount of Fe doping can break the local Ni-6Mn AFM configuration. Moreover, the Fe-doped samples reveal both the giant negative thermal expansion and near-zero thermal expansion for different temperature ranges. For instance, the average thermal expansion coefficient ā of x = 0.06 reaches −60.7 × 10−6/K over T = 231–338 K and 0.6 × 10−6/K over T = 175–231 K during cooling.

Simultaneous measurement of thermo-optic and thermal expansion coefficients with a single arm double interferometer.

A low-cost single arm double interferometer was developed for the concurrent measurement of linear thermal expansion (α) and thermo-optic (dn/dT) coefficients of transparent samples with plane and parallel surfaces. Owing to its common-path optical arrangement, the device is compact and stable, and allows the simultaneous measurement of interferences arising from a low-finesse Fabry-Perot etalon and from a Mach-Zehnder-type interferometer. The method was demonstrated with measurements of solid (silica, BK7, SF6) and liquid (water, ethanol and acetone) samples.

In-situ synthesis of AgCu/Cu2O nanocomposite by mechanical alloying: The effect of the processing on the thermal behavior

The influence of the mechanical alloying processing parameters on the elaboration of AgCu-based bimetallic matrix composites reinforced by in-situ synthesized Cu2O has been studied. The milling time (20, 45 and 80h) of the initial 72% mass Ag+28% mass Cu micrometric powders mixture influences the particle size distribution of the obtained composite particles. After 80h of mechanical alloying, AgCu/Cu2O nanoparticles of 60–80nm are obtained and their chemical composition at bulk/surface level has been determined by X-ray diffraction and photoelectron spectroscopy. The effect of milling time on the thermal behavior of the powders samples has been studied by thermogravimetry and differential scanning calorimetry measurements in argon atmosphere. The argon chemosorbtive reaction from the particles surface has been identified and the binding energy (0.9–1.99eV) has been calculated. The isothermal drop calorimetry and the linear thermal expansion measurements were used to evaluate the correlation between thermal stability and thermal expansion properties of the in-situ synthesized AgCu/Cu2O nanocomposite.

Magneto-Structural Properties and Magnetic Behavior of Fe-Pd Ribbons

Ribbons of Fe-Pd ferromagnetic shape memory alloys were prepared by rapid solidification via the melt-spinning technique. The effect of moderate and high temperature heat treatments on the martensitic transformation and the related changes of the magnetic behavior was analyzed by X-ray diffraction, differential scanning calorimetry and temperature, and field-dependent magnetometry. In addition, information about magnetic easy axis and magnetically field-induced strains (MFIS) were achieved from linear thermal expansion measurements performed under cooling at different applied fields. The observed low values of MFIS in the as-prepared ribbons are due, besides to the small size and random orientation of the grains, to the high atomic disorder inside the crystalline grains. The anisotropy field is enhanced by the reduced atomic disorder, as reflected by the increased MFIS values after thermal treatments.

High substitution of Fe3+ for Zr4+ in ZrV1.6P0.4O7 with small amount of FeV0.8P0.2O4 for low thermal expansion

Fe3+-doped ZrV1.6P0.4O7 with Fe:Zr molar ratios of 1:9, 2:8, 3:7 and 4:6 was synthesized to reduce phase transition and obtain low thermal expansion. It is shown that the phase transition temperature of Fe-doped ZrV1.6P0.4O7 is reduced obviously with increasing the content of Fe. Fe3+ ion with lower valence and smaller radius than that of Zr4+ favors to extend the bond angle of V–O–V(P) close to 180° in ZrV1.6P0.4O7, which is considered responsible for the normal structure at room temperature and low thermal expansion. The thermal expansion coefficients of Fe-doped ZrV1.6P0.4O7 for Fe:Zr molar ratios from 1:9 to 4:6 are calculated to be from −4.33×10−6 to 5.2×10−7K−1 by linear thermal expansion measurement. The effect of small amount of FeV0.8P0.2O4 formation with higher content of Fe3+ on thermal expansion coefficients of the samples is discussed.

Dielectric relaxation of 1-hydroxyadamantane

Electric properties were examined on polycrystalline samples of 1-hydroxyadamantane in the temperature range from 289 to 400K and the frequency range from 10 to 1000MHz. The frequency and temperature dependence of electric properties were analyzed using the Cole–Cole model of dielectric relaxation. The activation energy which describes the reorientation of 1-hydroxyadamantane, in the orientationally disordered phases, under electric field has been calculated. TGA and DSC measurements confirmed the presence of phase transitions. The linear thermal expansion measurement evidences that in the orientationally disordered phase (crI) the changes in the shape of the crystal are isotropic.

A study on magnetoelastic properties of Tb3 (Fe28−xCox) V1.0 (x=0, 3, 6) compounds

In this work, The magnetoelastic properties of polycrystalline samples of Tb3 (Fe28−xCox) V1.0 (x=0, 3, 6) intermetallic compounds are investigated by means of linear thermal expansion and magnetostriction measurements in the temperature range of 77–515K under applied magnetic fields up to 1.5T. The linear thermal expansion increases with the Co content. The well-defined anomalies observed in the linear thermal expansion coefficients for Tb3 (Fe28−xCox) V1.0 (x=0, 3, 6) compounds are associated with the magnetic ordering temperature for x=0 and spin reorientation temperatures for x=3, 6. Below transition temperatures, the value of the longitudinal magnetostriction (λPa) at 1.6T increases with Co content.

Dielectric relaxation of 1-bromoadamantane

Abstract Electric properties were examined on polycrystalline samples of 1-bromoadamantane in the temperature range from 273 K to 333 K and the frequency range from 10 MHz to 1000 MHz. The frequency and temperature dependence of electric properties were analysed using the Cole–Cole model of dielectric relaxation. The activation energy which describes the reorientation of 1-bromoadamantane, in the orientationally disordered phases, under electric field has been calculated. TGA and DSC measurements confirmed the presence of phase transitions. The linear thermal expansion measurement evidences that in the orientationally disordered phase (crI) the changes in the shape of the crystal are isotropic.

First-order structural transition in the magnetically ordered phase of Fe1.13Te

Specific heat, resistivity, magnetic susceptibility, linear thermal expansion (LTE), and high-resolution synchrotron X-ray powder diffraction investigations of single crystals Fe1+yTe (0.06 < y < 0.15) reveal a splitting of a single, first-order transition for y < 0.11 into two transitions for y > 0.12. Most strikingly, all measurements on identical samples Fe1.13Te consistently indicate that, upon cooling, the magnetic transition at T_N precedes the first-order structural transition at a lower temperature T_s. The structural transition in turn coincides with a change in the character of the magnetic structure. The LTE measurements along the crystallographic c-axis displays a small distortion close to T_N due to a lattice striction as a consequence of magnetic ordering, and a much larger change at T_s. The lattice symmetry changes, however, only below T_s as indicated by powder X-ray diffraction. This behavior is in stark contrast to the sequence in which the phase transitions occur in Fe pnictides.

Magnetic phase transition in MnFeP0.5As0.4Si0.1

We have carried out a detailed investigation of the magnetic phase transition in MnFeP0.5As0.4Si0.1. Temperature hysteresis has been observed in the variable temperature magnetization curves (Bappl = 0.01 T) with TCW ~ 302 K on warming and TCC ~ 292 K on cooling. The first order nature of this transition in MnFeP0.5As0.4Si0.1 is confirmed by the negative slope obtained from isotherms of M2 versus B/M around the critical temperature. Linear thermal expansion measurements reveal a large volume change, ΔV/V~8.7×10−3 at the magnetic phase transition and that this magnetovolume effect is suppressed to ΔV/V ~ 5.5×10−3in an applied field of Bappl = 1.0 T. Analyses of 57Fe Mössbauer spectra (4.5 – 300 K) using a random distribution model and taking nearest-neighbour environments into account, indicate that the paramagnetic and ferromagnetic phases coexist over a temperature range of ~ 45 K around the Curie temperature. The Debye temperature for MnFeP0.5As0.4Si0.1 has been evaluated as θD = 350 ± 20 K from the temperature dependence of the average isomer shift.

Electrical resistivity, high-resolution thermal expansion, and heat capacity measurements of the charge-density wave compoundγ−Mo4O11

Electrical resistivity of $\ensuremath{\gamma}\text{\ensuremath{-}}{\text{Mo}}_{4}{\text{O}}_{11}$ single crystals was measured using the Montgomery method. The results show a much smaller anisotropy than previously reported. High-resolution linear thermal expansion measurements reveal strongly anisotropic behavior. Both electrical resistivity and thermal expansion measurements suggest that this material should be classified as quasi-two dimensional. The thermal expansion coefficients exhibit an anomaly due to the charge-density wave transition along the $b$ and $c$ axes at $\ensuremath{\sim}100\text{ }\text{K}$.

Novel Quantum Criticality inCeRu2Si2near Absolute Zero Observed by Thermal Expansion and Magnetostriction

We report linear thermal expansion and magnetostriction measurements for CeRu2Si2 in magnetic fields up to 52.6 mT and at temperatures down to 1 mK. At high temperatures, this compound showed Landau-Fermi-liquid behavior: The linear thermal expansion coefficient and the magnetostriction coefficient were proportional to the temperature and magnetic field, respectively. In contrast, a pronounced non-Fermi-liquid effect was found below 50 mK. The negative contribution of thermal expansion and magnetostriction suggests the existence of an additional quantum critical point.

Analysis of the development of microscopic residual stresses on quartz particles in porcelain tile

This paper examines the development of microscopic residual stresses on quartz particles in porcelain tile using the XRD technique. The study was conducted with a typical porcelain tile composition consisting of sodium feldspar, kaolin, and quartz, using quartzes with different particle sizes. The methodology used, based on determining the volume strain of the quartz unit cell, allowed a residual stress value equivalent to the entire particle and not just to a given crystalline plane to be obtained. The linear thermal expansion measurements indicated that, for all test compositions, the quartz in the mixture contributes to a thermal expansion coefficient comparable to the expansion of its c-lattice parameter. When this information was taken into account in the theoretical estimation of microscopic residual stress, the results were verified to be consistent with the experimental measurements.

Magnetovolume effects in Dy 2Fe 17−xMn x

We have investigated the structural and magnetic properties of Dy 2Fe 17− x Mn x compounds ( x = 0 – 5.0 ) by X-ray diffraction, linear thermal expansion (LTE) and magnetization measurements. Compared with Dy 2Co 17− x Mn x compounds for which a linear increase of the unit cell volume with increasing Mn fraction is found, the composition dependence of the unit cell volume in the Dy 2Fe 17− x Mn x series exhibits a relative maximum around x∼0.5 before increasing monotonically for x⩾2; this behaviour can be ascribed to the existence of spontaneous volume magnetostriction as confirmed by LTE measurements. The Curie temperature ( T c) remains essentially constant (around 370 K) for Mn content up to x = 1 before decreasing steadily with increasing x, down to T C=232 K for Dy 2Fe 12Mn 5. The 3d-sublattice magnetization decreases monotonically with increasing Mn content.

The linear thermal expansion and the thermal diffusivity measurements for near-stoichiometric (U, Ce)O 2 solid solutions

The thermal diffusivities of near-stoichiometric (U, Ce)O 2 solid solutions containing CeO 2 up to 22 mol% were investigated in the temperature range of 298–1273 K using the laser flash method. Also, linear thermal expansion measurements were performed in the temperature range of 298–1673 K using a thermomechanical analysis. The thermal conductivities were determined by a calculation of the thermal diffusivity, the density and the specific heat. The thermal conductivities of the tested samples could be expressed as a function of the temperature by the phonon conduction equation k = ( A + BT) −1. The thermal conductivity decreased gradually with an increasing Ce content. This was attributable to the increasing lattice defect thermal resistance caused by the U 4+, Ce 4+ and O 2− ions as phonon scattering centers.

Specific Heat, Electrical Resistivity, and Linear Thermal Expansion of the Magnesium Alloy AE42 Measured by Subsecond Pulse Heating

Magnesium alloy AE42 (Mg with 4% Al and 2% rare earths) is used for the production of high-temperature creep-resistant castings. Its thermophysical properties are used as input parameters for the numerical simulation of the casting process by finite methods. Measurements of specific heat capacity, electrical resistivity, and linear thermal expansion of the magnesium alloy AE42 in the temperature range from 550 to 840 K by a transient technique are presented and discussed. Tubular specimens were Joule-heated from room temperature up to melting within 500 ms by a large current pulse. The current and the voltage drop along a defined portion of the specimen were measured by a fast precision data acquisition system. Temperature measurements were made with a high-speed broad-band infrared pyrometer. Thermal expansion was measured by a polarized-beam Michelson-type interferometer.