Normal Spectral Emittance — selected materials

Because emittance is what is actually measured for a sample, this is the term used in the graphs below. As we have said, emissivity is the term in popular usage, and is understood to mean the value the operator needs to enter into the pyrometer. Unfortunately, as will become apparent in the graphs below, there is always a choice of values.

The following graphs are reproduced from the Thermophysical Properties of Matter, Vol. 7: Thermal Radiative Properties, Y.S. Touloukian and D.P. DeWitt, IFI/Plenum, New York, 1970.

aluminum

Aluminum emissivity as a function of wavelength.

copper

Copper emissivity as a function of wavelength.

graphite

Graphite emissivity as a function of temperature.

iridium

Iridium emissivity as a function of wavelength.

iron

Iron emissivity as a function of wavelength.

molybdenum

Molybdenum emissivity as a function of wavelength.

silicon carbide

Silicon carbide emissivity as a function of wavelength.

stainless steel

Stainless steel emissivity as a function of wavelength.

titanium

Titanium emissivity as a function of wavelength.

tungsten

Tungsten emissivity as a function of wavelength.