Iron–nickel alloy

An iron–nickel alloy or nickel–iron alloy, abbreviated FeNi or NiFe, is a group of alloys consisting primarily of the elements nickel (Ni) and iron (Fe). It is the main constituent of the "iron" planetary cores and iron meteorites. In chemistry, the acronym NiFe refers to an iron–nickel catalyst or component involved in various chemical reactions, or the reactions themselves; in geology, it refers to the main constituents of telluric planetary cores (including Earth's).

Some manufactured alloys of iron–nickel are called nickel steel or stainless steel. Depending on the intended use of the alloy, these are usually fortified with small amounts of other metals, such as chromium, cobalt, molybdenum, and titanium.