Structural investigation of helium ion-beam-irradiated glassy carbon

Raman spectroscopy, high-resolution transmission electron microscopy, energy filtered electron diffraction, and electron energy loss spectroscopy were used to investigate the microstructural changes accompanying the observed ion-beam-induced enhancement of the abrasive wear properties of glassy carbon (GC). The Raman results suggested that doses of about 1×1016 He+ cm−2 at 600 keV were sufficient to seriously disrupt the structure. However, the electron-beam-based diagnostics failed to reveal any significant differences between the as-grown and irradiated material. It is suggested that the defect concentrations created by the ion beam are sufficient to disrupt the medium to short-range order in the material but insufficient to alter the overall structure. However, ion-beam thinning glassy carbon with 5-keV Ar ions was found to partially graphitize the material.