ISO 19618:2017
(Main)Fine ceramics (advanced ceramics, advanced technical ceramics) — Measurement method for normal spectral emissivity using blackbody reference with an FTIR spectrometer
Fine ceramics (advanced ceramics, advanced technical ceramics) — Measurement method for normal spectral emissivity using blackbody reference with an FTIR spectrometer
ISO 19618:2017 specifies a method used for the determination of normal spectral emissivity and normal quasi-total emissivity of fine ceramics using blackbody reference with a Fourier transform infrared spectrometer (FTIR) at elevated temperatures. This method is applicable to fine ceramics, ceramic matrix composites, and continuous fibre-reinforced ceramic matrix composites which are opaque and highly non-reflective at wavelengths between 1,67 μm and 25 μm. The applicable temperature range is approximately 350 K to 1 100 K.
Céramiques techniques — Méthode de mesure de l'émissivité spectrale normale utilisant un corps noir de référence avec un spectromètre FTIR
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 19618
First edition
2017-02
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Measurement method for normal
spectral emissivity using blackbody
reference with an FTIR spectrometer
Céramiques techniques — Méthode de mesure de l’émissivité spectrale
normale utilisant un corps noir de référence avec un spectromètre FTIR
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
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ii © ISO 2017 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
4 Principle . 2
5 Apparatus . 2
5.1 Measurement system. 2
5.2 Fourier transform infrared spectrometer (FTIR) . 2
5.3 Specimen heating device . 2
5.4 Blackbody furnace . 4
5.5 Temperature measuring devices and thermometer . 4
5.6 Mirror . 4
6 Test specimens. 4
7 Measurement preparation . 6
7.1 Position of a blackbody furnace and a specimen . 6
7.2 Wavelength calibration . 6
7.3 Verification of linearity . 6
7.4 Verification of stability . 6
7.5 Validation of measurement system . 6
8 Test condition . 7
9 Test procedure . 7
9.1 Background infrared radiance spectrum measurement . 7
9.2 Specimen installation . 7
9.3 Infrared radiance spectrum measurement . . 7
10 Calculations. 7
10.1 Normal spectral emissivity . 7
10.2 Normal quasi-total emissivity . 8
11 Test report . 9
Annex A (informative) Calculation of theoretical infrared radiance spectrum L(λ,T) using
Planck’s blackbody radiation function .10
Annex B (informative) Christiansen effect .11
Annex C (informative) Validity of normal quasi-total emissivity .12
Bibliography .13
Foreword
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
iv © ISO 2017 – All rights reserved
INTERNATIONAL STANDARD ISO 19618:2017(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Measurement method for normal spectral
emissivity using blackbody reference with an FTIR
spectrometer
1 Scope
This document specifies a method used for the determination of normal spectral emissivity and normal
quasi-total emissivity of fine ceramics using blackbody reference with a Fourier transform infrared
spectrometer (FTIR) at elevated temperatures. This method is applicable to fine ceramics, ceramic
matrix composites, and continuous fibre-reinforced ceramic matrix composites which are opaque and
highly non-reflective at wavelengths between 1,67 μm and 25 μm. The applicable temperature range is
approximately 350 K to 1 100 K.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60584-2, Thermocouples — Part 2: Tolerances
IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms, definitions and symbols
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
emissivity
ε
ratio of the radiant emittance of a substance (specimen) to the radiant emittance of a blackbody (3.2) at
the same temperature
3.2
blackbody
ideal thermal radiator that absorbs all incident radiation completely, whatever the wavelength,
direction of incidence or polarization
3.3
spectral emissivity
ε (λ, T)
s
emissivity (3.1) of a specimen at a defined wavelength λ and temperature T
3.4
normal spectral emissivity
ε (λ, T)
ns
emissivity (3.1) perpendicular to the specimen at a defined wavelength λ and temperature T
3.5
normal total emissivity
ε (T)
n
ratio of the normal component of the total emissive power of a specimen surface to the normal
component of the total emissive power of a blackbody at the same temperature T
3.6
normal quasi-total emissivity
ε (λ , λ , T)
n 1 2
normal emissivity between λ and λ at temperature T
1 2
Note 1 to entry: Calculated as the ratio of the normal component of the emissive intensity of a specimen between
λ and λ to the normal component of the emissive intensity of a blackbody between λ and λ at the same
1 2 1 2
temperature T.
4 Principle
The infrared radiance spectrum data from a specimen surface and from a blackbody furnace are
measured using an FTIR spectrometer. The normal spectrum emissivity of a specimen is determined
by direct comparison to a blackbody reference data at the same temperature.
Integrating the infrared radiance spectrum data in the specified wavelength range numerically, normal
quasi-total emissivity is calculated.
5 Apparatus
5.1 Measurement system
The measurement system consists of a Fourier transform infrared spectrometer (FTIR), specimen
heating device, blackbody furnace, and temperature measuring devices as shown in Figure 1.
5.2 Fourier transform infrared spectrometer (FTIR)
Infrared radiation from a specimen or a blackbody furnace is let into a Mickelson interferometer of
an FTIR through an external optical path. Thereby, an interferogram of infrared radiation is obtained.
The infrared radiance spectrum is obtained numerically by Fourier transformation processing from
the interferogram.
The optical system including a Mickelson interferometer of an FTIR shall be filled with dry N or dry air of
which the dew point is lower than 220 K to reduce the effect of H O and CO in air. Vacuum may be used.
2 2
The measurement spot area at the sample position and at the blackbody furnace positions shall be
measured preliminarily.
5.3 Specimen heating device
A specimen shall be heated using a heating device such as electrical resistance heating elements,
heat-pipes, heat-transfer media, etc. The specimen surface temperature shall be well controlled to
within ± 3 K.
An example of a specimen heating device is depicted in Figures 2 and 3.
2 © ISO 2017 – All rights reserved
Key
1 blackbody furnace
2 specimen heating device
3 specimen
4 FTIR spectrometer
5 switchable mirror
6 external optical path
Figure 1 — Measurement system
Key
1 specimen
2 hot plate (block)
3 resistance heater elements
4 thermal insulator
5 cavity
Figure 2 — Example of a specimen heating device: electrical resistance furnace
Key
1 specimen
2 device body
3 channel for heat transfer media
4 inlet
5 outlet
Figure 3 — Example of a specimen heating device: heat transfer media
5.4 Blackbody furnace
Total emissivity of a black
...
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