MAGNETOVOLUME AND CHEMICAL BONDING EFFECTS OF NI ATOM IN GAMMA'-(FE1-XNIX)(4)N COMPOUNDS

By X-ray diffraction and high pressure Mossbauer spectroscopy, the str ucture and the hyperfine parameters of Ni substituted gamma-Fe4N were investigated. The results of X-ray diffraction indicate that single ph ase gamma'-(Fe1-xNix)(4)N compounds can be prepared in the composition range of 0 less than or equal to x less than or equal to 0.6, and wit h the increase of Ni content the lattice parameter is fit for the rela tionship a(0)(x)= 3.790 5 - 0.021 57 x - 0.031 67 x(2). By high pressu re Mossbauer spectra, effects of magnetovolume and chemical bonding of Ni atom on hyperfine magnetic field and isomer shift of iron were dis tinguished for the first time, and their composition dependences for d ifferent lattice sites were studied simultaneously. It is found that t he magnetovolume and chemical bonding have different influences on the properties of gamma-(Fe1-xNix)(4)N, and the latter one plays a key ro le in the property changes of gamma'-(Fe1-xNix)(4)N.