Native metal of the Chelyabinsk meteorite
V. E. Roshchin, Yu. N. Goikhenberg, D. M. Galimov
Russian Metallurgy (Metally)
May 2014, Volume 2014, Issue 5, pp 419-425
The so-called native metal of the Chelyabinsk meteorite consists of relatively large particles of iron-nickel solid solutions at various ratios of the components in contact with complex iron-nickel sulfides, small (<1 μm) iron particles disseminated in olivine, and copper particles in contact with metal sulfide aggregates based on iron and nickel. The following three phases are detected in the iron-nickel metallic particles: bcc α solid solution with 3.5–5.5 at % Ni, fcc γ solid solution with 35–43 at % Ni, and an ordered iron-nickel phase with a cubic lattice. The metals from the rock that is similar to the oxide part of the meteorite substance are subjected to selective solid-phase reduction under laboratory conditions. As a result, the formed metal is similar to the native metal of the meteorite in particle distribution, particle size, and structure. It is concluded that the native metal of the meteorite can be the product of the decomposition of its thermodynamically unstable compounds with oxygen and sulfur under the action of space vacuum and heating during the passage of the parent asteroid along the segment of its elliptical orbit that is nearest to the Sun.