INST.No.INE-378-P9CE
- 43 -
8. Reference
The emissivity are values determined by the material of object, profile of its surface, surface roughness,
oxidized or not, measuring temperature, measuring wavelength and other factors.
They are represented by the thermal radiation ratio "
" when a black body furnace at the same
temperature is measured in the same wavelength band.
The emissivity "
" is generally known by a value at the wavelength of 0.65µm when an optical pyrometer
is used. The emissivity changes according to the above factors even in case of the same material. Please
use the following table as a reference.
8.1 Emissivity table
8.1.1 Emissivity table (
= 0.65µm)
Metal
Emissivity
Oxide
Emissivity
Solid
Liquid
Zinc
0.42
―
Alumel
（
*
）
0.87
Alumel
0.37
―
Chromel(*
）
0.87
Aluminum
0.17
0.12
Constantan
（
*
）
0.84
Antimony
0.32
―
Ceramics
0.25 to 0.5
Iridium
0.30
―
Cast iron
（
*
）
0.70
Yttrium
0.35
0.35
55Fe. 37.5Cr. 7.5Al
（
*
）
0.78
Uranium
0.54
0.34
70Fe. 23Cr. 5Al. 2Co
（
*
）
0.75
Gold
0.14
0.22
80Ni. 20Cr
（
*
）
0.90
Silver
0.07
0.07
60Ni. 24Fe. 16Cr
（
*
）
0.83
Chromium
0.34
0.39
Stainless steel
（
*
）
0.85
Chromel P
0.35
―
Aluminum oxide
0.22 to 0.4
Cobalt
0.36
0.37
Yttrium oxide
0.60
Constantan
0.35
―
Uranium oxide
0.30
Zirconium
0.32
0.30
Cobalt oxide
0.75
Mercury
―
0.23
Columbium oxide
0.55 to 0.71
Tin
0.18
―
Zirconium oxide
0.18 to 0.43
Carbon
0.8 to 0.9
―
Tin oxide
0.32 to 0.60
Tungsten
0.43
―
Cerium oxide
0.58 to 0.82
Tantalum
0.49
―
Titanium oxide
0.50
Cast iron
0.37
0.40
Iron oxide
0.63 to 0.98
Titanium
0.63
0.65
Copper oxide
0.60 to 0.80
Iron
0.35
0.37
Thorium oxide
0.20 to 0.57
Copper
0.10
0.15
Vanadium oxide
0.70
Thorium
0.54
0.34
Beryllium oxide
0.07 to 0.37
Nickel
0.36
0.37
Magnesium oxide
0.10 to 0.43
80Ni /20Cr
0.35
―
60Ni / 024Fe / 16Cr
0.36
―
(*) : Oxidized on surfaces
Platinum
0.30
0.38
90Pt / 10Rh
0.27
―
Palladium
0.33
0.38
Vanadium
0.35
0.35
Bismuth
0.29
―
Beryllium
0.61
0.61
Manganese
0.59
0.59
Molybdenum
0.37
0.40
Rhodium
0.24
0.30
