High resolution transmission electron microscopic study of the formation of Fe16N2 in bulk iron by ion implantation

High purity iron sheets were implanted with high-dose nitrogen ions accelerated to 150 keV. The implanted surfaces were examined by thin-film X-ray diffraction method and high resolution transmission electron microscopy (HRTEM). The implanted surfaces contain the metastable Fe 16 N 2 phase in addition to ϵ-nitride. HRTEM reveals that Fe 16 N 2 domains have lattice fringes of double spacing along the [121] direction of the matrix and spherical morphologies with coherent interfaces.