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.