Comparison between surface properties of F- and HF-implanted glassy carbon

A study has been made on the influence of H-atoms to the surface properties of F- and HF-implanted glassy carbon (GC). F- and HF-ions were implanted with the doses ranging from 5×1014 to 5×1016 ions at the energy of 150 keV at room temperature. The structure, compositions and surface morphology of implanted layers were measured using laser Raman spectroscopy, SIMS and AFM, respectively. Tribological properties were investigated using a ball-on-disk wear tester, and wettability was estimated by means of measurements of contact angles of water. The Raman spectra for high doses indicate the formation of amorphous carbon. The depth profiles of F-atoms for HF implantations show the peak shifts toward the surface as the dose increases. Hydrogen profiles show two peaks near the surface and the average range, and they are expanded with a high dose. The high dose increases the surface roughness for F-implantation, and in contrast, HF-implantation retains the surface smoothness. The implantations of F- and HF- ions caused the friction coefficient to be stable and lower, the wear resistance to improve and the wettability to be unvaried. In conclusion, HF-ion implantation improves the tribological properties of GC, retaining the surface smoothness.