The spectral emittance of nickel- and oxide-coated nickel cathodes
S L Martin et al 1950 Br. J. Appl. Phys. 1 318-324

Abstract. The spectral emittance values at a wavelength ? = 0.66 ? have been measured for various types of oxide-coated cathode, and for nickel cores, using a cylindrical diffuse reflectometer…”