Deutsch | Español | Français | 简体中文

IR Technology Banner
About us >> Emissivity - Metals

Emissivity Values for Metals

Emissivity is the measure of an object's ability to emit infrared energy. Emitted energy indicates the temperature of the object. Emissivity can have a value from 0 (shiny mirror) to 1.0 (blackbody). Most organic, painted, or oxidized surfaces have emissivity values close to 0.95. The majority of our IR sensors have an adjustable emissivity feature to ensure accuracy when measuring other materials, such as shiny metals.

Please note, these values are to be used as a guide only, as emissivity changes depending on the actual material surface and conditions.

Material Emissivity Values
  1.0µm 1.6µm 8-14µm
Aluminum      
  Unoxidized 0.1-0.2 0.02-0.2 n.r.
  Oxidized 0.4 0.4 0.2-0.4
Alloy A3003      
  Oxidized n.r. 0.4 0.3
  Roughened 0.2-0.8 0.2-0.6 0.1-0.3
  Polished 0.1-0.2 0.02-0.1 n.r.
Brass      
  Polished 0.8-0.95 0.01-0.05 n.r.
  Burnished n.r. n.r. 0.3
  Oxidized 0.6 0.6 0.5
Chromium 0.4 0.4 n.r.
Copper      
  Polished n.r. 0.03 n.r.
  Roughened n.r. 0.05-0.2 n.r.
  Oxidized 0.2-0.8 0.2-0.9 0.4-0.8
Electrical Terminal Blocks n.r. n.r. 0.6
Gold 0.3 0.01-0.1 n.r.
Haynes      
  Alloy 0.5-0.9 0.6-0.9 0.3-0.8
Inconel      
  Oxidized 0.4-0.9 0.6-0.9 0.7-.95
  Sandblasted 0.3-0.4 0.3-0.6 0.3-0.6
  Electoropolished 0.2-0.5 0.25 0.15
Iron      
  Oxidized 0.4-0.8 0.5-0.9 0.5-0.9
  Unoxidized 0.35 0.1-0.3 n.r.
  Rusted n.r. 0.6-0.9 0.5-0.7
  Molten 0.35 0.4-0.6 n.r.
Iron, Cast      
  Oxidized 0.7-0.9 0.7-0.9 0.6-0.95
  Unoxidized 0.35 0.3 0.2
  Molten .035 0.3-0.4 0.2-0.3
Iron, Wrought      
  Dull 0.9 0.9 0.9
Lead      
  Polished 0.35 0.05-0.2 n.r.
  Rough 0.65 0.6 0.4
  Oxidized n.r. 0.3-0.7 0.2-0.6
Magnesium 0.3-0.8 0.05-0.3 n.r.
Mercury n.r. 0.05-0.15 n.r.
Molybdenum      
  Oxidized 0.5-0.9 0.4-0.9 0.2-0.6
  Unoxidized 0.25-0.35 0.1-0.35  
Nickel      
  Oxidized 0.8-0.9 0.4-0.7 0.2-0.5
  Electrolytic 0.2-0.04 0.1-0.3 n.r.
Platinum      
  Black n.r. 0.95 0.9
  Silver n.r. 0.02 .n.r
Steel      
  Cold-Rolled 0.8-0.9 0.8-0.9 0.7-0.9
  Ground Sheet n.r. n.r. 0.4-0.6
  Polished Sheet 0.35 0.25 0.1
  Molten 0.35 0.25-0.4 n.r.
  Oxidized 0.8-0.9 0.8-0.9 0.7-0.9
  Stainless 0.35 0.2-0.9 0.1-0.8
Tin (Unoxidized) 0.25 0.1-0.3 n.r.
Titanium      
  Polished 0.5-0.75 0.3-0.5 n.r.
  Oxidized n.r. 0.6-0.8 0.5-0.6
Tungsten (Wolfram) n.r. 0.1-0.6 n.r.
  Polished 0.35-0.4 0.1-0.3 n.r.
Zinc      
  Oxidized 0.6 0.15 0.1
  Polished 0.5 0.05 n.r.

n.r.=not recommended

To optimize surface temperature measurement accuracy:
1. Determine the object emissivity for the spectral range of the instrument to
be used for the measurement.
2. Avoid reflections by shielding object from surrounding high temperature sources.
3. For higher temperature objects, use shorter wavelength instruments, whenever possible.