The results of experimental investigation of the quasi-binary alloy 60 mas. % GdB6 40 mas. % VB2 are represented. The values of highest thermionic current density, electron work function, and spectral emissivity are determined at the temperature range from 1285 to 1944 K. This composition cathode material not only poisons but also considerably increases of electron emission at the air and oxygen leaking. The stable increase of emission current takes place after stopping of oxygen leaking at Т = 1700…1800 К.