Atom-probe tomography and transmission electron microscopy of the kamacite–taenite interface in the fast-cooled Bristol IVA iron meteorite

Surya S. Rout*, Philipp R. Heck, Dieter Isheim, Thomas Stephan, Nestor J. Zaluzec, Dean J. Miller, Andrew M. Davis, David N. Seidman

*Corresponding author for this work

Research output: Contribution to journalArticle

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Abstract

We report the first combined atom-probe tomography (APT) and transmission electron microscopy (TEM) study of a kamacite–tetrataenite (K–T) interface region within an iron meteorite, Bristol (IVA). Ten APT nanotips were prepared from the K–T interface with focused ion beam scanning electron microscopy (FIB-SEM) and then studied using TEM followed by APT. Near the K-T interface, we found 3.8 ± 0.5 wt% Ni in kamacite and 53.4 ± 0.5 wt% Ni in tetrataenite. High-Ni precipitate regions of the cloudy zone (CZ) have 50.4 ± 0.8 wt% Ni. A region near the CZ and martensite interface has <10 nm sized Ni-rich precipitates with 38.4 ± 0.7 wt% Ni present within a low-Ni matrix having 25.5 ± 0.6 wt% Ni. We found that Cu is predominantly concentrated in tetrataenite, whereas Co, P, and Cr are concentrated in kamacite. Phosphorus is preferentially concentrated along the K-T interface. This study is the first precise measurement of the phase composition at high spatial resolution and in 3-D of the K-T interface region in a IVA iron meteorite and furthers our knowledge of the phase composition changes in a fast-cooled iron meteorite below 400 °C. We demonstrate that APT in conjunction with TEM is a useful approach to study the major, minor, and trace elemental composition of nanoscale features within fast-cooled iron meteorites.

Original languageEnglish (US)
Pages (from-to)2707-2729
Number of pages23
JournalMeteoritics and Planetary Science
Volume52
Issue number12
DOIs
StatePublished - Dec 2017

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ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science

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