Thermophysical properties and normal spectral emittance of Iridium up to 3500 K

"Thermophysical properties and normal spectral emittance of Iridium up to 3500 K",

International Journal of Thermophysics Vol. 28(2), p. 697-710, http://dx.doi.org/10.1007/s10765-007-0188-9, (2007) by C. Cagran, G. Pottlacher

C. Cagran¹ and G. Pottlacher¹ Contact Information
(1) Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Published online: 10 May 2007
"An ohmic pulse-heating experiment together with radiometry and ?s-photopolarimetry is deployed at the Institute of Experimental Physics, Graz University of Technology, to obtain temperature-dependent thermophysical properties of conducting samples in the solid and molten states..."

"This experimental setup has been used within the present work to gather data for solid and liquid iridium. Results for both thermophysical properties, as well as the normal spectral emittance obtained at a wavelength of 684.5 nm up to 3500 K are reported. The newly obtained values for iridium are presented in graphical and tabular form and compared to available literature data. The uncertainties for all reported properties are stated and it follows that, considering these expanded uncertainties, the recent data are in very good agreement with literature sources. Mutually motivated by these good results and by the scarce (if any) data available for the liquid state, the thermal conductivity and thermal diffusivity of liquid iridium are estimated by means of the Wiedemann–Franz law."

Keywords: ellipsometry - iridium - normal spectral emittance - pulse-heating - thermal conductivity - thermal diffusivity - thermophysical properties

Modeling of the thermal radiative behavior of rough coatings

Abstract 675 - Monte Carlo modeling of the thermal radiative behavior of rough coatings

Presented in the session Photothermal Techniques. Theory and Modeling at the 18th European Conference on Thermophysical Properties, Pau, France 31 Aug-4 Sep 2008
By:
Mr Hector Gomarta*+
Dr Benoit Rousseaua
Dr Domingos De Sousa Menesesa
Dr Patrick Echeguta

a CNRS Orléans
CEMHTI
Site Haute Température
1D avenue de la Recherche Scientifique
45071 cedex 02, France

*: Corresponding author
+: Presenting author

ABSTRACT:

Surface roughness plays a crucial role in the thermal radiative properties of industrial systems, such as infrared heaters, plate near blackbody references used to calibrate a pyrometric setup. Nevertheless literature usually reports radiative properties simulations only for several wavelengths. In this study, we focus on modeling emissivity over a wide IR-spectral range for surfaces either measured by profilometry or numerically rebuild.

Handbook of OSML Libraries: Emittance

CRMHT - CNRS Centre de Recherche sur les Matériaux à Haute Température, Orléans, France
Mesure indirecte de l'émittance (Includes sample data for Silicon Dioxide)

Mesure de la réflectivité et de la transmissivité normales spectrales (10 à 40 000 cm-1 soit 1 000 à 0,25 µm).

L'émissivité normale spectrale se déduit indirectement par calcul de ces deux grandeurs par application des lois de Kirchhoff ,

i.e. at each wavelength, Emissivity =1 - Reflectivity - Transmissity

Emittance-WN

Handbook of OSML Libraries

	E - dielectric function N - complex refractive index RT - reflectivity, layer transmissivity WN - wave number
OSML Source : [Emitttance-WN]
Function Group : [Optical Functions]

Emittance-E

Emittance-E (AE) represents the fraction of the incident radiation that is absorbed (Kirchhoff law) by a sample with a plate shape. Its expression take into account for multiple reflections (no interference effects) and depends on the dielectric functions of the incident medium Ei, those of the material Eo and the thickness d of the sample. Function signature : Emittance-E(x,Ei,Eo,Thickness)Units The spectral dependence must be expressed in wave numbers (cm-1) and the thickness in (cm).

Emittance-N

Emittance-N (AN) represents the fraction of the incident radiation that is absorbed (Kirchhoff law) by a sample with a plate shape. Its expression take into account for multiple reflections (no interference effects) and depends on the complex refractive indexes of the incident medium Ni, those of the material No and the thickness d of the sample. Function signature : Emittance-N(x,Ni,No,Thickness)Units The spectral dependence must be expressed in wave numbers (cm-1) and the thickness in (cm).

Emittance-RT

Emittance-RT (ART) represents the fraction of the incident radiation that is absorbed (Kirchhoff law) by a sample with a plate shape. Its expression take into account for multiple reflections (no interference effects and depends on the reflectivity R and the layer transmissivity T of the sample. Function signature : Emittance-RT(R,T)

Planck-WN

Planck-WN (PWN) is the wave number version of the Planck function. Its expression depends on the temperature T. Function signature : Planck-WN(x,T) Constants : C1=1.1910 10-6 (W.m2) C2=1.4388 (cm.K)

See Also : [Optical Functions] [Reflectance-WN] [Transmittance-WN]
Handbook of OSML Libraries

Emissivity Calculator Online

The Pyrometer Instrument Company, manufacturers of the Pyrolaser® and Pyrofiber® products, among others, have a unique, online emissivity calculator that enables one to calculate the temperature measurement effect of: wavelength, emissivity setting and temperature for Infrared measurement wavelength bands ranging from 0.655 micrometer to 10.6 micrometers.

You can access the calculator by CLICKING HERE

(Pyrometer Instrument Company, 92 North Main Street • Bldg 18-D • Windsor, NJ 08561 • USA
Telephone: (609) 443-5522 • Fax: (609) 443-5590 • Email: sales [at] pyrometer.com)

EMISSIVITY EVALUATION OF FIXED POINT BLACKBODIES

A paper by Sergey Mekhontsev, Vladimir Khromchenko, Alexander Prokhorov, Leonard Hanssen
National Institute for Standards and Technology, Gaithersburg, MD, USA

Presented at the 9th International Symposium on Temperature and Thermal Measurements in Industry and Science (TEMPMEKO 2004), June 22-25, 2004, Dubrovnik, Croatia, Proceedings, Vol. 1, ed. by D. Zvizdic (2004), pp. 581-586.

ABSTRACT

A new facility for the characterization of infrared spectral emittance of materials has recently been developed at NIST. The facility operation is based on measurements of a sample’s spectral radiance and surface temperature with help of a set of variable temperature blackbodies and a spectral comparator. For highest accuracy, variable temperature blackbodies are calibrated in spectral radiance against a pair of fixed-point blackbodies with interchangeable crucibles of In, Sn, and Zn, and Al, Ag, and Cu, respectively. The spectral emissivity of the fixed-point blackbodies also needs to be accurately characterized. We employ a multi-prong approach: (1) Monte Carlo ray-trace modeling and calculations, (2) hemispherical reflectance measurements of the crucible cavity material flat sample, as well as the cavity itself, (3) direct spectral emittance measurements of the same samples using the facility, and (4) comparison of the fixed point blackbodies with each other as well as with variable temperature heat pipe blackbodies, using filter radiometers and the facility’s Fourier transform spectrometer. The Monte Carlo code is used to predict the cavity emissivity with input of the cavity shape and the emissivity and specularity of the cavity material. The reflectance measurements provide emissivity data of both the material and the cavity at room temperature. The results are used to compare with and validate the code results. The direct emittance measurements of the material provide the temperature dependence of the material emittance as code input. The code predicted results for the cavities at their operating temperature (freeze points) are then compared with the relative spectral radiance measurements. Use of this complete set of evaluation tools enables us to obtain the spectral emissivity of the blackbodies with reliably determined uncertainties.

It presently can be downloaded in PDF format from the NIST website by CLICKING HERE