DAMAGE PROCESS IN ELECTRON-IRRADIATED GRAPHITE STUDIED BY TRANSMISSION ELECTRON-MICROSCOPY .1. HIGH-RESOLUTION OBSERVATION OF HIGHLY GRAPHITIZED CARBON-FIBER

Electron irradiation damage of highly graphitized carbon fibre was exa mined by means of transmission electron microscopy in a multibeam latt ice imaging mode together with selected-area electron diffraction. It was found that the (00.2) lattice spacing was homogeneously increased up to about 11% over the whole irradiated area with increasing irradia tion time. The structural order parallel to the basal plane gradually deteriorated, although that perpendicular to the basal planes was comp aratively retained. Computer image simulations based on possible model structures so far proposed, in which interstitial atom clusters are i ncorporated, could not explain the homogeneous dilation of (00.2) latt ice fringes. An unconventional idea must be considered for the damage process in graphite.