General Tools and Instruments GTi10-20-30-50 - Manual (Page 61)

61
Appendix III
Emissivity of Common Materials
Material Temperature (°C Emissivity
METALS
Aluminum
Polished aluminum 100 0.09
Commercial aluminum foil 100 0.09
Electrolytic chromeplate alumina 25 600 0.55
Mild alumina 25 600 0.10 0.20
Strong alumina 25 600 0.30 0.40
Brass
Brass mirror (highly
polished)
28 0.03
Brass oxide 200 600 0.61 0.59
Chrome
Polished chrome 40 1090 0.08 0.36
Copper
Copper mirror 100 0.05
Strong copper oxide 25 0.078
Cuprous oxide 800 1100 0.66 0.54
Liquid copper 1080 1280 0.16 0.13
Gold
Gold mirror 230 630 0.02
Iron
Polished cast iron 200 0.21
Processed cast iron 20 0.44
Polished tempered iron 40 250 0.28
Polished steel ingot 770 1040 0.52 0.56
Raw welded steel 945 1100 0.52 0.61
Surface ferric oxide 20 0.69
Completely rusty surface 22 0.66
Rolled iron plate 100 0.74
Oxidized steel 198 600 0.64 0.78
Cast iron (Oxidizing at 600°C) 198 600 0.79
Steel (Oxidizing at 600°C ) 125 520 0.78 0.82