Application of Norbury Rule to Thermal Conductivity in Intermetallic Compounds

1994 ◽  
Vol 364 ◽  
Author(s):  
Yoshihiro Terada ◽  
Tetsuo Mohri ◽  
Tomoo Suzuki
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Laser Flash ◽  
Flash Method ◽  
Horizontal Distance ◽  
Conductivity Data ◽  
Host Metal ◽  
Thermal Conductivity Λ

AbstractThermal conductivity data at room temperature, which are measured by laser-flash method, are presented in B2 aluminides and titanides, and in nickel based L12 compounds. The thermal conductivity λ is changed in the following order of the compounds. λ(NiAl) >λ(CoAl)>λ(FeAl), λ(NiTi)<λ(CoTi)<λ(FeTi), λ(Ni3Al)>λ(Ni3Si) and λ(Ni3Ga)>λ(Ni3Ge). According to Norbury rule originally proposed for the concentration dependence of electrical resistivity, the increasing rate is greater in the solid solution, where the position of solute elements is more remote in horizontal distance from a host metal in the periodic table. It is found that this rule holds for the thermal conductivity measured for the intermetallic compounds with the combination of a series of guest constituents and a fixed host constituent both in the B2 and Ll2 intermetallic compounds.

scholarly journals Determination of the effective thermal conductivity of solid fuels by the laser flash method

2014 ◽  
Vol 35 (3) ◽  
pp. 3-16 ◽  
Author(s):  
Monika Kosowska-Golachowska ◽  
Władysław Gajewski ◽  
Tomasz Musiał
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Laser Flash ◽  
Physical Structure ◽  
Solid Fuels ◽  
Flash Method ◽  
Hard Coal ◽  
Coal Rank ◽  
Dominant Effect

Abstract In this study, a new laser flash system was proposed for the determination of the thermal conductivity of brown coal, hard coal and anthracite. The main objective of the investigation was to determine the effect of coal rank, composition, physical structure and temperature on thermal conductivity. The solid fuels tested were medium conductors of heat whose determined thermal conductivities were in the range of 0.09 to 0.23W/(mK) at room temperature. The thermal conductivity of the solid fuels tested typically increased with the rank of coal and the measurement temperature. The results of this study show that the physical structure of solid fuels and temperature have a dominant effect on the fuels’ thermal conductivity.

Regression Model Describing the Thermal Conductivity of Various Cast Irons

2010 ◽  
Vol 649 ◽  
pp. 499-504 ◽  
Author(s):  
Daniel Holmgren ◽  
Martin Selin
Keyword(s):  
Thermal Conductivity ◽  
Image Analysis ◽  
Regression Analysis ◽  
Silicon Content ◽  
Digital Image Analysis ◽  
Laser Flash ◽  
Flash Method ◽  
Conductivity Data ◽  
Cast Irons ◽  
Etching Technique

The thermal conductivity of various grades of pearlitic cast iron has been modelled with good results by means of regression analysis. The experimental thermal conductivity data, which the modelling is based on, were obtained by the laser flash method. The microstructure was investigated by digital image analysis combined with a colour etching technique. The model developed takes the carbon content, the silicon content, the nodularity as well as the fraction of cementite into consideration. The graphite morphologies of the samples investigated were lamellar, compacted and spheroidal.

scholarly journals Thermal conductivity measurement of infrared optical fibers based on silver halide solid solution crystals

2021 ◽  
Vol 2127 (1) ◽  
pp. 012052
Author(s):  
A Turabi ◽  
B P Zhilkin ◽  
L V Zhukova ◽  
A S Shmygalev ◽  
A V Rudenko ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Optical Fibers ◽  
Thermal Conductivity Coefficient ◽  
Silver Halide ◽  
Conductivity Measurement ◽  
Laser Flash ◽  
Flash Method ◽  
Production Technologies ◽  
Light Guides

Abstract The aim of the study is to measure the thermal conductivity of silver halide light guides based on crystals of the AgCl-AgBr system used in PSD production technologies. The conductivity temperature coefficient of the samples under study were determined by the laser flash method using the LFA 467 (Hyper Flash) installation. We studied mono- and polycrystalline samples of solid solutions with the composition AgCl0,25AgBr0,75 in the temperature range 298–523 K. The thermal conductivity of the investigated materials was then calculated using literature data on density and heat capacity. The thermal conductivity coefficient ranges from 0.80±0,04 to 0.53±0,03 (W/mK), depending on the microstructure of the sample.

scholarly journals XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Влияние неидеальности геометрической формы образца на неопределенность измерений теплопроводности методом лазерной вспышки

2019 ◽  
Vol 53 (6) ◽  
pp. 731
Author(s):  
А.В. Асач ◽  
Г.Н. Исаченко ◽  
А.В. Новотельнова ◽  
В.Е. Фомин ◽  
К.Л. Самусевич ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Measurement Uncertainty ◽  
Conductivity Measurement ◽  
Laser Flash ◽  
Comsol Multiphysics ◽  
Flash Method ◽  
Cylindrical Shape ◽  
Plane Parallel ◽  
Coefficient Of Thermal Conductivity ◽  
Truncated Cylinder

The influence of the geometric shape of the samples on the uncertainty of the coefficient of thermal conductivity measurement of materials by the method of a laser flash has been studied. Using a method of mathematical modeling in the Comsol Multiphysics software, a model that simulates the process of measuring the coefficient of thermal conductivity of samples made of graphite, Mg2Si0.4Sn0.6 and bismuth telluride using a laser flash method has been created. Samples of cylindrical shape with plane-parallel sides and samples in the form of a truncated cylinder, as well as samples in the form of a parallelepiped with a square base, were investigated. It is shown that the measurement uncertainty of samples with plane-parallel sides and sizes up to 12.7 mm, does not exceed 2%. For samples in the form of a truncated cylinder with a diameter of 3 mm and at an angle of ϕ= 1.5°, the measurement uncertainty does not exceed 3%. With an increase in the sample diameter and the ϕ angle, the measurement uncertainty increases significantly.

Study on Thermal Conductivity of Polyetheretherketone/Thermally Conductive Filler Composites

2007 ◽  
Vol 124-126 ◽  
pp. 1079-1082 ◽  
Author(s):  
Sung Ryong Kim ◽  
Dae Hoon Kim ◽  
Dong Ju Kim ◽  
Min Hyung Kim ◽  
Joung Man Park
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Carbon Fiber ◽  
Conductive Filler ◽  
Laser Flash ◽  
Flash Method ◽  
Phase System ◽  
Two Phase ◽  
Nielsen Theory ◽  
Thermally Conductive

Thermal properties of PEEK/silicon carbide(SiC) and PEEK/carbon fiber(CF) were investigated from ambient temperature up to 200°C measured by laser flash method. Thermal conductivity was increased from 0.29W/m-K without filler up to 2.4 W/m-K with at 50 volume % SiC and 3.1W/m-K with 40 volume % carbon fiber. Values from Nielsen theory that predicts thermal conductivity of two-phase system were compared to those obtained from experiment.

Laser flash method for measuring thermal conductivity of liquids. Application to molten salts

1981 ◽  
Vol 20 (4) ◽  
pp. 333-336 ◽  
Author(s):  
Yutaka Tada ◽  
Makoto Harada ◽  
Masataka Tanigaki ◽  
Wataru Eguchi
Keyword(s):  
Thermal Conductivity ◽  
Molten Salts ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method

Temperature Dependence of Thermal Conductivity of Electronic Ceramics by an Improved Flash Diffusivity Technique

1989 ◽  
Vol 167 ◽  
Author(s):  
R. C. Enck ◽  
R. D. Harris
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Ceramic Materials ◽  
Laser Flash ◽  
Flow Measurements ◽  
Electronic Ceramics ◽  
Temperature Dependences ◽  
Commercial Sources ◽  
Materials Used ◽  
Flash Diffusivity

AbstractThe thermal conductivity of ceramic materials used for IC substrates and packages has increased in importance as chip sizes have decreased and heat loads have risen. AIN which has a room temperature (RT) thermal conductivity (λ) greater than 200 W/m·K and BeO with λ(RT) ∼260 W/m·K are the major candidates for applications demanding high conductivity. Conflicting reports of the temperature dependences of λ for these materials over the range of interest for packaging use (≤200°C) have been published, with some reports suggesting a crossover in λ. These reported differences may be due to the reported problems in measuring λ in AIN using the flash diffusivity method. For the present experiments, we have used a new long wavelength laser flash diffusivity system which has been shown to determine thermal diffusivity to better than ± 3% for AIN with sample thicknesses ranging from 0.3 mm to 5 mm. No absorbinq coatings are required and no correction factors are needed to fit the data to theory. We report λ from room temperature to 400°C for AIN from a number of commercial sources, and for BeO and SiC. At room temperature, BeO has the highest thermal conductivity, but as the temperature is raised, the values for BeO and AIN approach one another, with crossover observed at about 350°C for the highest conductivity AIN sample studied. Recent steady state heat flow measurements agree with our thermal conductivity values rather than with previous literature values.

Thermoelectric Properties of Phase Separated Composite of Ln-Doped SrTiO3 and TiO2 Micro Crystals

2007 ◽  
Vol 1044 ◽  
Author(s):  
Kiyoshi Fuda ◽  
Kenji Murakami ◽  
Shigeaki Sugiyama
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Fine Particles ◽  
Bulk Material ◽  
Laser Flash ◽  
Flash Method ◽  
Helium Atmosphere ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Thermal Diffusivities

AbstractIt seems that no satisfactory TE property has been found in n-type oxide bulk materials even though Al-doped ZnO and La-doped SrTiO3 have high thermoelectric (TE) responses. Difficulty in developing high-performance TE materials seems to lie in finding low thermal conductivity in such oxides. The purpose of this study is to find a possibility to make an n-type TE oxide bulk material having low thermal conductivity and excellent TE properties as well. For this purpose, we fabricated and examined a series of composites constructed of TiO2 and Ln-doped SrTiO3 fine crystals. The composites were prepared via two processing steps: (1) precursor oxide preparation by wet processes; (2) sintering by using spark plasma sintering (SPS) apparatus. The microscopic structure was examined by using scanning electron microscope (SEM; HITACHI S-4500 model) attached with an energy dispersive x-ray spectroscopy. The electrical conductivities and the Seebeck coefficients were measured simultaneously using an ULVAC ZEM-1 instrument in helium atmosphere. The thermal diffusivities were measured by a laser flash method in vacuum. The composites obtained here were found to commonly have a mosaic type texture constructed of TiO2 and SrTiO3 fine particles with a typical size of 500 nm. The thermal conductivity values measured for three samples with different contents are ranged between 3 and 4 Wm-1K-1 in the temperature range from room temperature to 800 C. The values are apparently lower than the value for single crystal SrTiO3 samples presented in literature. Taking account the other TE data, e.g. Seebeck coefficient and electrical conductivity, we calculated dimensionless figure of merit, ZT, to be at maximum 0.15 at 800°C.

scholarly journals The difference in the thermal conductivity of nanofluids measured by different methods and its rationalization

2016 ◽  
Vol 7 ◽  
pp. 2037-2044 ◽  
Author(s):  
Aparna Zagabathuni ◽  
Sudipto Ghosh ◽  
Shyamal Kumar Pabi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Laser Flash ◽  
Flash Method ◽  
Transfer Model ◽  
Measuring Methods ◽  
Order Of Magnitude ◽  
Wire Method ◽  
The Difference ◽  
First Time

A suspension of particles below 100 nm in size, usually termed as nanofluid, often shows a notable enhancement in thermal conductivity, when measured by the transient hot-wire method. In contrast, when the conductivity of the same nanofluid is measured by the laser flash method, the enhancement reported is about one order of magnitude lower. This difference has been quantitatively resolved for the first time on the basis of the collision-mediated heat transfer model for nanofluids proposed earlier by our research group. Based on the continuum simulation coupled with stochastic analysis, the present theoretical prediction agrees well with the experimental observations from different measuring methods reported in the literature, and fully accounts for the different results from the two measuring methods mentioned above. This analysis also gives an indication that the nanofluids are unlikely to be effective for heat transfer in microchannels.

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