Phase equilibria in the Fe-Nb-Zr system at 1,200 ℃ were determined by X-ray diffraction （XRD） and scanning electron microscope （SEM） coupled with energydispersive X-ray spectroscopy （EDS） techniques. Extensive NbFez domain was proposed in the current work. This compound existed in the composition range from 35 at% to 73 at% Fe, 12 at% to 32 at% Nb, and 0 to 32 at% Zr. In the present work, four three-phase regions （1）-（Nb,Zr） ＋ NbFe ＋ NbFe2, （2） [3-（Nb,Zr） ＋ NbFe2 ＋ Liquid, （3） NbFe2 ＋ Liquid ＋ ZrFe2, and （4） ZrFe2 ＋ Fe ＋ NbFe2, were established.
