Electro Optical Industries (EOI) uses one of two high emissivity coatings on the surface of its blackbodies.
The EOI mid-temperature coating is used on both cavity and flat plate blackbodies that have a maximum operating temperatures of up to 210 °C.

Read the rest by visiting their webpage at: www.electro-optical.com/html/bb_rad/emissivity/emis_data.asp