Measurements Of Expansion Coefficient Research Articles

Design and application testing of imaging probe for strain measurement

To address the challenge of obtaining key device strain parameters within narrow spaces, this paper presents the design of a small-sized optical imaging probe with an independent optical system based on the basic principle of digital image correlation (DIC). To validate the strain measurement accuracy of the probe, a high-temperature heating system was built under in a laboratory setting, and experimental tests involving room temperature strain measurement and high temperature thermal expansion coefficient measurement were conducted. The findings demonstrate the potential of the developed probe for strain measurement in critical components situated in restricted spaces.

Uncertainty Quantification of Thermophysical Property Measurement in Space and on Earth: A Study of Liquid Platinum Using Electrostatic Levitation

A study of uncertainty analysis was conducted on four key thermophysical properties of molten Platinum using a non-contacting levitation technique. More specifically, this work demonstrates a detailed reporting of the uncertainties associated with the density, volumetric thermal expansion coefficient, surface tension and viscosity measurements at higher temperatures for a widely used refractory metal, Platinum using electrostatic levitation (ESL). The microgravity experiments were conducted using JAXA’s Electrostatic Levitation Furnace (ELF) facility on the International Space Station and the terrestrial experiments were conducted using NASA’s Marshal Space Flight Center’s ESL facility. The performance of these two facilities were then quantified based on the measurement precision and accuracy using the metrological International Standards Organization’s Guide to the Expression of Uncertainty Measurement (GUM) principles.

High-Accuracy Thermal Expansion Coefficient Measurement Based on Fiber-Optic EFPIs With Automatic Temperature Compensation

High-Accuracy Thermal Expansion Coefficient Measurement Based on Fiber-Optic EFPIs With Automatic Temperature Compensation

Development of Pyros Alloy as a Certified Reference Material for Thermal Expansion Coefficient Measurements

The push-rod dilatometer is the most widely used and popular commercial apparatus for measuring the thermal expansion coefficient of metals, it should be metrological verified before testing. Certified reference materials are the most applicable and effective means of verifying such equipment. Here, a reference material [termed Pyros (Ni-based) alloy] was developed for measuring the thermal expansion coefficient. The Pyros alloy reference material exhibited a high thermal expansion coefficient: a range of 12.7–16.8 (× 10–6 °C−1). The maximum temperature of the certified value was 1000 °C. This range and value almost span the entire application needs of metals, especially steel alloy or superalloys. Thus, Pyros alloy is suitable as a reference material for validating the push-rod dilatometer based on comparative measurements.

Defect Chemistry Engineering Promotes the Dopability of Cu for an Extraordinary Thermoelectric Performance of Hole-Doped PbSe with Resonant States

Cu substitution for Pb (CuPb) has been theoretically predicted to introduce resonant states near the valence band edge of PbSe. However, experimentally, it has not been verified yet due to the extremely low solubility (∼0.3 atom %) of CuPb. In this study, we demonstrate that the solubility limit of CuPb is extended to at least 1.5 atom % in PbSe by pairing with an identical amount of Cu interstitials (Cui), while excess Cu precipitates out as a Cu2Se phase at grain boundaries. As a result of the increased dopability of CuPb, a significant enhancement of the Seebeck coefficient is realized in hole-doped PbSe because of CuPb-induced resonant states. This is also testified by first-principles calculations. Moreover, the rich point defects (CuPb, Cui), line defects (dislocations), and Cu2Se precipitates remarkably frustrate the phonon propagation of PbSe, leading to ∼45% reduction of lattice thermal conductivity (κlat) at room temperature. At elevated temperatures (>623 K), there is a dynamic migration of Cu atoms from Cu2Se precipitates to tetrahedral interstices of the PbSe matrix as evidenced by the temperature-variant Hall study and thermal expansion coefficient measurement. This diffusion-like process of Cu further drops the κlat to ∼0.27 W m–1 K–1 at 823 K. Consequently, a peak ZT of ∼1.8 at 873 K is achieved in the (Cui)0.01Pb0.97(CuPb)0.01Na0.02Se sample. This work highlights the potential of the defect structure design in innovating new functional materials, particularly high-performance thermoelectrics.

Preparation and Properties of Ce0.8Sm0.16Y0.03Gd0.01O1.9-BaIn0.3Ti0.7O2.85 Composite Electrolyte

Samarium, gadolinium, and yttrium co-doped ceria (Ce0.8Sm0.16Y0.03Gd0.01O1.9, CSYG) and BaIn0.3Ti0.7O2.85 (BIT07) powders were prepared by sol-gel and solid-state reaction methods, respectively. CSYG-BIT07 composite materials were obtained by mechanically mixing the two powders in different ratios and calcining at 1300 °C for 5 h. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as electrical properties and thermal expansion coefficient (TEC) measurements. A series of CSYG-BIT07 composite materials with relative densities higher than 95% were fabricated by sintering at 1300 °C for 5 h. The performance of the CSYG-BIT07 composite electrolyte was found to be related to the content of BIT07. The CSYG-15% BIT07 composite exhibited high oxide ion conductivity (σ800°C = 0.0126 S·cm−1 at 800 °C), moderate thermal expansion (TEC = 9.13 × 10−6/K between room temperature and 800 °C), and low electrical activation energy (Ea = 0.89 eV). These preliminary results indicate that the CSYG-BIT07 material is a promising electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs).

Two-Dimensional Displacement Sensor Based on a Dual-Cavity Fabry-Perot Interferometer

Simultaneously and independently measuring two-dimensional (2D) displacement, one-dimensional (1D) for out-of-plane measurement and 1D for in-plane measurement, is important for practical applications. Although extrinsic fiber Fabry-Perot interferometers (EFPIs) have been reported for highly precise out-of-plane displacement measurements for many years, simultaneous measurement of 2D displacement with sub-micrometer accuracy has not been realized by a monolithic EFPI as far as we know. In this paper, a monolithic dual-cavity EFPI to realize 2D displacement measurement of a target is reported. By quantitatively analyzing and experimentally calibrating the linear dependences of the in-plane displacement sensitivity and interception on the cavity length, the effect of out-of-plane displacement on the in-plane displacement measurement is removed, which is the basis of the 2D displacement detection. 2D random movement detection and the repeatability of the system are investigated experimentally. Within the range of ±7 μm for in-plane displacement, and 352 μm-358 μm for cavity length, demodulation errors better than 96 nm are achieved. The 2D displacement measurement system based on the dual-cavity EFPI with the advantages of noncontact, high accuracy and compact size is promising to be applied in the 2D acceleration measurement, 2D rotor vibration measurement, 2D precise positioning in semiconductor manufacture, thermal expansion coefficient measurement, and so on.

Evaluation of Tensile and Thermal Properties of Alumite Using Al Alloy Specimen Having Anodized Layer

Aluminum alloys used i internal combustion engines have been coated with an alumite layer. Conventionally, the alumite layer has been provided to suppress thermal cracking. Recently, it has been found that the alumite layer is effective in improving the thermal efficiency of internal combustion engines. To evaluate the strength reliability of those anodized parts, it is necessary to understand the tensile and thermal properties of anodized aluminum. In this study, we proposed a method based on the rule of mixtures to evaluate the tensile deformation behavior and the linear coefficient of expansion of the alumite. Al alloy specimens with and without anodized treatment were used to conduct tensile tests at R.T., 473 K, 573 K, 623 K, and linear expansion coefficient measurement tests. By using the stress-strain relations obtained from the tensile tests, the tensile stress-strain relations of the alumite layers were estimated and they were used to discuss the tensile characteristics of the alumite layers. As a result, the stress-strain relation and linear expansion coefficient of the alumite could be estimated. It was also found that the alumite has higher strength than Al alloys at RT., 473 K, 573 K, and 623 K.

Experimental Teaching Reform and Practice Based on the Ability Cultivation of Material Undergraduates

Taking the teaching practice of “material thermal expansion coefficient measurement experiment” as an example, focusing on the multi-level experimental teaching objectives of cultivating undergraduates’ rigorous scientific attitude, autonomous learning ability and practical innovation ability of material-major undergraduates, this paper describes how to design and expand experimental teaching content, guide students to control the details of the experimental operation, preset questions to guide students to think actively, refine experimental knowledge points, and so on, and achieve the capability cultivation of talents throughout the whole process of experimental teaching. Furthermore, it is proposed that experimental teachers in colleges and universities should strengthen autonomic learning actively and deepen the construction of experimental courses and improve the quality of talent cultivation under the background of deepening the educational reform.

Lanthanum Strontium Cobaltite-Alumina Fiber Composite Contact Material for Solid Oxide Fuel Cells

Lanthanum strontium cobaltite (LSCo) is considered a good candidate as cathode contact materials for SOFC applications, due to its high electrical conductivity as compared to the standard LSM materials. However, it suffers very poor thermal cycle stability because large mismatch in CTE. To overcome the large residual stress, we proposed to use strong and short alumina fiber to enforcement the LSCo matrix. Alumina in vol% from 2.5 to 20% were formulated and prepared for sintering study, thermal expansion coefficient measurement, phase characterization, bulk strength, and contact strength evaluation before and after 10 deep thermal cycles. Results showed the presence of rigid alumina fiber did retard the densification of LSCo matrix substantially at high alumina content. Bulk strength showed increasing trend at low alumina content but decreased at high alumina v%, likely due to severe retardation in densifications. Contact strength on 1”x1” bilayer showed the strong bonding at low alumina v% while good thermal cycle stability was observed. The candidate composite was further tested in a stack fixture using 2”x2” cell. Results of impedance versus cycling and microstructure and fracture analysis will be discussed to assess the validity of fiber reinforced LSCo as contact material.

EMC 특성이 FOWLP 웨이퍼 변형에 미치는 영향

Wafer was shrunk and expanded during post-mold cure and staging on the room temperature. The primary cause for wafer shrinkage during cure process is related with evaporation of solvent in EMC. Suitable temperature for pre-mold cure is defined as 103 ± 2~3℃ to minimize the wafer shrinkage during this cure process. The die drift variation according to ±5℃ of temperature variation during post-mold cure was very small. From the thermal expansion coefficient measurement, the thermal expansion coefficients taken on EMC A and B samples were 23.9ppm/K and 8.1ppm/K respectively, indicating wafer deformation of sample B was relatively small as compared with sample A.

Space Environment Exposure Effects on Ceramic Coating for Thermal Protection Systems

Carbon/carbon (C/C) structures are widely considered for space thermal protection systems (TPSs), being able to withstand critical reentry conditions thanks to an excellent thermal stability. In low-Earth-orbit long-time missions, however, the TPS effectiveness is significantly lowered due to the surfaces’ prolonged staying within the harsh space environment. In particular, the detrimental oxidation due to thermal cycles and atomic oxygen (AtOx) exposure greatly affects the TPS integrity, thus leaving the spacecraft’s outer surface less protected during reentry. A great effort is thus made for testing solutions based on advanced coatings aimed at preserving TPS materials from oxidation. In the present work, ceramic coatings are evaluated by measurements of the thermal expansion coefficient and AtOx erosion rate. The specimens tested are C/C substrates on which commercial refractory varnishes are applied. Silicon carbide and aluminum and zirconium oxides are the basic ceramic constituents, and the effect of silica nanoparticles’ inclusion on the coating performances is also evaluated. A phenomenological modeling is then introduced to approach the relationship between erosion mechanism due to AtOx impact and surface energy variation induced by thermal cycles; such analysis highlights the importance of considering the combined action of different aging factors, in order to achieve a reliable interpretation of the space environment’s effect on spacecraft structures and subsystems.

Evaluation and analysis of the uncertainty measurement linear thermal expansion coefficient of ceramic brick

With the continuous and high-speed growth of economy, people's requirements on product quality are increasing year by year, including ceramic brick products, which, as a typical building materials product, are widely used in all kinds of buildings of different sizes. Quality of brick of pottery and porcelain products mainly in the form of through the examination and evaluation. The uncertainty of measurement as an important part of the test results, is an important parameter characterization of the reliability of the measurement result. Therefore, this paper, the source of uncertainty in linear thermal expansion coefficient measurement of ceramic brick is analyzed, using the measurement results and related data, and concludes that for the linear thermal expansion coefficient average of 0.016%. when the report 2 sample average, the expanded uncertainty U (A) = 1.48%, contains the factor k = 2.

Push-rod dilatometer calibration and thermal expansion coefficient measurement of standard material

The linear thermal expansion coefficient (LTEC) is a very important thermal property in the field of length standard, precision engineering and novel material science. There are several methods in measuring the LTEC of a material and the push-rod type is a one of the frequently used method. In this work, the calibration and the measurement procedures of the SRM 736 which is a certified material provided from NIST are carried out with push-rod type dilatometer (Dil402, NETZSCH) and the results are presented in the temperature range from 300°C to 500°C. The calibration of thermocouple and a linear variable differential transformer (LVDT) sensor have been performed with the melting point of the pure metals and the calibration device consisting of the rod and micrometer provided from the NETZSH.

Rapid suppression of the energy gap and the possibility of a gapless hidden order state in URu2−xRexSi2

ABSTRACTWe investigated the energy gap associated with the hidden order (HO) phase and the Grüneisen ratio in the URuReSi system using a combination of thermal expansion coefficient and specific heat measurements. As the HO phase transition is suppressed to lower temperature, the ratio between the energy gap and the HO transition temperature decreases three-fold. This rapid suppression of the energy gap potentially leads to a scenario of a ‘gapless’ HO state, in which the energy gap of the HO phase vanishes before the HO transition temperature is suppressed to 0 K. We also investigated the Grüneisen ratio in the vicinity of the Re substituent composition where the HO is suppressed. The Grüneisen ratio shows divergent behaviour at x=0.12 and 0.15, providing evidence for the existence of a quantum critical point, which is consistent with our hypothesis of a ‘gapless’ HO state.

Heat-capacity measurements of sandstone at high temperatures

To evaluate geothermal energy generation systems, we must predict the amount of heat present and the rate at which it can be extracted. These two factors—amount of heat and recovery rate—in turn depend on the basic physical properties of the reservoir rocks. The amount of heat present in a reservoir depends on the heat capacity CP of the rocks. The heat capacity of the rocks is needed to evaluate energy storage, Q = (1 − ϕ)ρCP(T)T, where ϕ is the porosity, ρ is the density, CP is the heat capacity, and T is the temperature. For global heat balances, the mean specific heat between two extreme temperatures T1 and T2, can be defined as \(Q = \frac{1}{{T_{2} - T_{1} }}\int\nolimits_{{T_{1} }}^{{T_{2} }} {C_{P} \left( T \right)dT}\), where CP(T) is the temperature-dependence of the heat capacity. For dynamic processes, the value of heat-capacity at each given temperature is needed. The area under a CP(T) curve between any two temperature limits yields an enthalpy change as \(\Delta H = \int\nolimits_{{T_{1} }}^{{T_{2} }} {C_{P} \left( T \right)dT}\). In the present work we have detailed study of the temperature dependence of the heat capacity (CP) of sandstone over the temperature range from 308 to 763 K using a differential scanning calorimeter model of 204 F1. The combined expanded uncertainty of the heat capacity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 1%. A rapid increase (from 1.06 to 1.85 kJ kg−1 K−1) of the measured heat capacities above the classical value (3R) in the high-temperature range above 575 K was observed. This increase at high temperatures can be explained as being due to microstructural changes during heating of the sample (the microstructural effect), which was confirmed by thermal expansion coefficient measurements. The effect of microstructural changes (“thermal cracking”) on the temperature behavior of heat-capacity of sandstone was studied. Theoretically-based correlations for the heat capacity were adopted to accurately represent the measured data. The measured CP(T) data for sandstone were used to check the accuracy, predictive capability, and applicability of various correlation models proposed in the literature. The proposed correlation equations for the heat capacity are based on the present experimental data that have been critically assessed for consistency with other measured properties and for agreement with theory whenever possible.

Thermal expansion coefficient measurement from electron diffraction of amorphous films in a TEM

We measured the linear thermal expansion coefficients of amorphous 5–30 nm thick SiN and 17 nm thick Formvar/Carbon (F/C) films using electron diffraction in a transmission electron microscope. Positive thermal expansion coefficient (TEC) was observed in SiN but negative coefficients in the F/C films. In case of amorphous carbon (aC) films, we could not measure TEC because the diffraction radii required several hours to stabilize at a fixed temperature.

Measurement of cryogenic thermal expansion coefficient and accuracy analysis

In order to realize the high-precision measurement of the thermal expansion coefficient of the infrared material under the cryogenic vacuum environment, a measurement scheme of solid material is proposed. Based on the self-collimation principle, this scheme designs a microstructure, establishes the relationship between structural deformation and angle, and deduces the formula of thermal expansion coefficient measurement. Using the measurement formula, this article analyzes the relationship between the measurement error transfer function of the scheme, and also uses the error sensitivity function to analyze the design accuracy of cryogenic thermal expansion coefficient measuring device for infrared materials, and finally the relative error of the scheme is calculated. The thermal expansion coefficient of the scheme is measured to be only 0.76%, which satisfies the nanometer measurement requirement.

Single-spot two-dimensional displacement measurement based on self-mixing interferometry

The simultaneous and independent measurements of in-plane and out-of-plane displacements are significant issues to be solved in research. Here a novel system to realize single-spot two-dimensional (2D) displacement measurement of a noncooperative target is reported. The performance of the system is tested in the displacement measurement of an aluminum target with a rough surface. 2D random movement and 2D movement with different parameters of Lissajous figures are measured by the system. The ranges of the 2D displacement measurement reach 500 μm and the accuracies reach the submicron scale. The resolutions of the two dimensions are all better than 5 nm. The measurement system is based on laser heterodyne self-mixing interferometry with frequency multiplexing, which has advantages such as noncontact, nondestruction, nanometer-scale resolution and high sensitivity. The method is promising to be applied in 2D deformation tests of materials, 2D rotor vibration measurement, 2D positioning of particles, thermal expansion coefficient measurement, and other applications.

Effect of CuO addition on crystallization and thermal expansion properties of Li2O–ZnO–SiO2 glass-ceramics

A Li2O-ZnO-SiO2 (LZS) glass system was modified with CuO, and its phase development, microstructure evolution, crystallization kinetics and thermal expansion properties were investigated as a function of heat treatment temperature. As a result of the X-ray diffraction study and microstructure observation, lithium zinc silicate formed as the first crystalline phase with increasing heat treatment temperature. Silica polymorph developed as minor crystalline phase at higher temperatures. From the X-ray diffraction patterns, CuO addition led to a decrease in both the crystallization temperature of lithium zinc silicate phase and the volume fraction of quartz phase. According to the crystallization kinetics, the crystallization activation energy for lithium zinc silicates is almost equal to the diffusion activation energy of Zn2+ in glass, it suggests that the diffusion of network modifier Zn2+ dominates the crystallization of lithium zinc silicates. Additionally, CuO addition caused the transition of Zn2+ from network modifiers to network formers. From the thermal expansion coefficient measurements, two abrupt changes in slope of the thermal expansion curves were observed and attributed to the phase transitions of cristobalite and lithium zinc silicate, respectively. Comparison of the thermal expansion coefficient of two types of glass-ceramics revealed that CuO addition in the LZS system can partly inhibit the formation of cristobalite at high temperatures.