Material
Condition
Temperature-
Range
Emissivity-
factor (ɛ)
Iron
With red rust
20°C
0.61 ... 0.85
elektrolytic polished 175°C ... 225°C
0.05 ... 0.06
Wrought with
sandpaper
20°C
0.24
oxidized
100°C
125°C ... 525°C
0.74
0.78 ... 0.82
Hot-rolled
20°C
0.77
Hot-rolled
130°C
0.6
Laquer
Bakelite
80°C
0.93
black, matt
40°C ... 100°C
0.96 ... 0.98
black, high-glossed,
sprayed onto iron
20°C
0.87
Heat-resistant
100°C
0.92
white
40°C ... 100°C
0.80 ... 0.95
Lamp
black
-
20°C ... 400°C
0.95 ... 0.97
Application to solid
surfaces
50°C ... 1000°C
0.96
With water glass
20°C ... 200°C
0.96
Paper
black
normal
Temperature
0.90
black, matt
dto.
0.94
green
dto.
0.85
Red
dto.
0.76
White
20°C
0.7 ... 0.9
yellow
normal
Temperature
0.72
-53-
