57 Fe hyperfine parameters and phase compositions in Fe-Ni-Co alloys from iron, stony-iron and stony meteorites

Basing on Mössbauer studies of various iron, stony-iron and stony meteorites, we considered a possible relationship of the ranges of magnetic hyperfine field ( H eff ), Fe-Ni-Co phases and the ranges of Ni concentration in these phases. We suppose that possible relationship of the ranges of H eff with Fe-Ni-Co phases and with the ranges of Ni concentration can be taken as follows: ~345 kOe ≤ H eff ≤ ~365 kOe for the α 2 -phase (~ 8–25 at% of Ni), ~ 327 kOe < H eff ≤ ~345 kOe for the α-phase (up to 7 at% of Ni), ~ 283 kOe ≤ H eff ≤ ~327 kOe for the γ-phase (~ 26–48 at% of Ni) with the values of ~ 283 kOe ≤ H eff ≤ ~295 kOe which may also be associated with the ordered γ-FeNi(Co) phase (~ 48–52 at% of Ni). The paramagnetic γ-Fe(Ni, Co) phase with ~ 29–33 at% of Ni has the values of isomer shift ( δ ) in the range of ~ − 0.200 mm/s < δ < ~0.150 mm/s.