Structure of ion implanted graphite fibers.

This paper reports on the effect of ion implantation on the structure of highly ordered benzene-derived graphite fibers (BDGF) using high resolution transmission electron microscopy (TEM). Emphasis is given to the dependence of the in-plane and c-axis crystallite sizes and of the interlayer spacing on ion species and fluence. Our results show a decrease in crystallite size with increasing ion mass and fluence, and an increase in the interlayer spacing with increasing ion mass. Preliminary results on post-ion implantation annealing give activation energies of ~ 0.5 eV/atom for both the in-plane and the c-axis recrystallization processes. Our annealing studies show that the c-axis interplanar spacing is larger than 3.36angstroms even for annealing temperatures of 2800C, which is well above the threshold for three-dimensional ordering.