STRUCTURAL AND CHEMICAL BONDING INVESTIGATION OF TUNGSTEN IMPLANTED GLASSY-CARBON

Recently it has been shown that in addition to an ion beam induced enhancement in wear resistance, glassy carbon (GC) irradiated with W ions also shows a substantially enhanced resistance to hydrogen plasma erosion. In order to understand the origins of these improvements in the properties of W implanted GC, cross-sectional transmission electron microscopy and Auger profiling spectrometry is used to study GC implanted with 60 keV W ions to doses up to 1.5 x 10(17) ionS/cm2. Transmission electron microscopy images of the implanted region show that W implantation leads to the formation of an amorphous surface layer for doses between 3.8 x 10(14) and 6 x 10(15) ionS/cm2. The density of the implanted layer is shown to increase from 1.55 to 2.3 g/cm3 for W doses up to 6 x 10(15) ions/cm2. The enhancement in wear resistance observed in W implanted GC is most likely due to the formation of a dense amorphous surface layer. Auger profiling measurements indicate that the enhanced resistance to hydrogen plasma erosion is likely to be due to the formation of carbidic bonding within the modified region.