FORMATION OF FE16N2 IN IRON SHEET BY AN ION-IMPLANTATION METHOD

High purity iron sheets with and without cold rolling are implanted us ing two methods of high dose nitrogen ions: ( I) single-implantation a ccelerated to 150 keV, and (2) multi-implantation accelerated to a ser ies of voltages of 100, 150 and 200 keV. The iron nitride formed at th e iron surface was studied by Auger electron spectroscopy, the grazing incident X-ray diffraction method with incident angles ranging from 1 degrees to 10 degrees and transmission electron microscopy. Fe16N2 wa s formed with high density in the iron sheet by multi-implantation tha n by the single accelerated voltage. Lattice ratio (c/a) of tetragonal crystal of Fe16N2 increased to about 1.1 with an aging treatment at 3 93 K after the implantation. Highly dense Fe16N2 particles were formed at cold rolled and aged Fe sheets. (C) 1998 Elsevier Science S.A. All rights reserved.