gamma-NiFe2N with the face centered cubic symmetry, rather than the hexagonal symmetric epsilon-NiFe2N in previous reports, was synthesized by treating NiFe2 alloy in an ammonia atmosphere. Compared with the NiFe2 sample, the gamma-NiFe2N exhibited the strong ferromagnetism, giant magnetostriction, high resistivity and good corrosion resistance. The unique properties of gamma-NiFe2N expand its applications. Besides, as a magnetostriction material, gamma-NiFe2N does not contain any resource-critical rare-earth elements and it is over ten times lower cost than the rare-earth doped Galfenol or Terfenol-D alloys because Ga, Tb or Dy is very expensive. (C) 2017 Elsevier Ltd. All rights reserved.