kamaciet

Kamacite, also referred to as kamaciet in some languages, is an iron–nickel alloy found chiefly in iron meteorites. In English, kamacite is the low-nickel phase of the Fe–Ni system, typically containing about 5 to 10 percent nickel. It contrasts with taenite, a higher-nickel phase (roughly 20 to 50 percent Ni) that is usually more nickel-rich. Kamacite is commonly associated with the body-centered solid-solution form that characterizes low-nickel iron alloys, whereas taenite is often face-centered.

Occurrence and identification

Kamacite occurs as a primary constituent of iron meteorites and is frequently intermixed with taenite, producing the characteristic Widmanstätten patterns seen on etched surfaces. These patterns arise from long-term slow cooling in the meteorite parent body, which allows nickel to diffuse and segregate into distinct kamacite and taenite regions. The two phases can appear as elongated blades or blocks within a metallic matrix.

Formation and distribution

Formed during the cooling of metallic iron–nickel melts in space, kamacite represents the earlier-formed, nickel-poor material. Its distribution within a meteorite, and the resulting kamacite–taenite intergrowths, provide information about cooling rates and thermal history of the meteoritic body.

Properties and significance

Kamacite is a metallic, relatively soft and ductile alloy with a density near that of iron. It is primarily of interest to mineralogists and meteoriticists, serving as a key clue to the crystallization and thermal processes in meteorite parent bodies. It has little practical use outside of scientific study and collection.