X-RAY-DIFFRACTION AND MOSSBAUER STUDIES OF THE (FE1-XNIX)(4)N COMPOUNDS LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5)

X-ray diffraction and Mossbauer spectroscopy studies on the gamma-Fe4N type (Fe1-xNix)(4)N compounds (0 less than or equal to x less than or equal to 0.5) were performed. The lattice constants decrease with inc reasing x. Compared with Fe1-xNix alloys of the same composition, the average relative expansion of the unit cell (delta V/V) is 16.7% after nitriding. The results of the Mossbauer spectra of the (Fe1-xNix)(4)N are well in agreement with the structure in which the nickel atoms ar e prior to locating at the Fe-c sites, and some of the nickel atoms al so occupy the face center sites in the meantime. The iron atoms at the Fe-c sites are completely occupied by nickel atoms, when x greater th an or equal to 0.5.