Structure of ion implanted graphite fibers

¹ Shinshu University, Nagano-shi 380, Japan.
² Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
³ AT & T Bell Laboratories, Murray Hill, NJ 07974, USA.

Abstract

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 ~ 0.7 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 3.36 A even for annealing temperatures of 2800 °C, which is well above the threshold for three-dimensional ordering.

Résumé

L'effet d'implantation d'ions sur la structure de fibres de graphite ex-benzène est examiné par microscopie électronique à haute résolution. Les résultats montrent une diminution de la dimension des cristallites et une agumentation de distance interplanaire lorsque la masse de l'ion augmente.