Microindentation measurements of glassy carbon implanted with high-energy titanium ions

Changes in the microstructure and mechanical properties of the surface of glassy carbon implanted with 1.15 MeV Ti ions were examined by Rutherford backscattering spectrometry, Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy and ultra-microindentation measurements. It was found that the surface of glassy carbon was changed to an amorphous structure by Ti ion implantation. The thickness of the amorphous layer, as estimated by the transport of ions in matter (TRIM) simulation, was approximately 1 mu m. The glassy carbon surface is composed of many granules which were also increased in size by ion implantation. However, this increase in size was sufficiently small compared with the indenter radius that it had only a minor influence at an early stage of the indentation measurements. The implanted Ti was in the carbide state of TiC. The hardness and elastic modulus were increased by approx. 2.5- and 3.5-fold due to the modification in structure by ion implantation. (C) 1998 Elsevier Science S.A.