An iron–nickel alloy or nickel–iron alloy, abbreviated FeNi or NiFe, is a group of
alloys consisting primarily of the
nickel (Ni) and
iron (Fe). It is the main constituent of the "iron"
planetary cores and
iron meteorites. The acronym NiFe refers to various
chemical reactions that involve an iron–nickel
catalyst or component, or in
geology, to the general composition of planetary cores (including
Some iron–nickel alloys are called nickel steel and usually contain additional elements, depending on the purpose.