ISO 19618:2017

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

General Information

• Status: Published
• Publication Date: 13-Feb-2017
• ICS: 81.060.30 - Advanced ceramics
• Technical Committee: ISO/TC 206 - Fine ceramics
• Drafting Committee: ISO/TC 206/WG 7 - Monolithic ceramics/Physical and thermal properties
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 03-Feb-2023

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 19618:2017(E)
ISO 2017
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ISO 19618:2017(E)
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© ISO 2017, Published in Switzerland

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ii © ISO 2017 – All rights reserved
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ISO 19618:2017(E)
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

© ISO 2017 – All rights reserved iii
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ISO 19618:2017(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

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This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.
iv © ISO 2017 – All rights reserved
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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

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)
emissivity (3.1) of a specimen at a defined wavelength λ and temperature T
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ISO 19618:2017(E)
3.4
normal spectral emissivity
ε (λ, T)

emissivity (3.1) perpendicular to the specimen at a defined wavelength λ and temperature T

3.5
normal total emissivity
ε (T)

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.
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