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 Rut herford backscattering spectrometry, Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy and ultra-microindentatio n measurements. It was found that the surface of glassy carbon was cha nged to an amorphous structure by Ti ion implantation. The thickness o f the amorphous layer, as estimated by the transport of ions in matter (TRIM) simulation, was approximately 1 mu m. The glassy carbon surfac e is composed of many granules which were also increased in size by io n implantation. However, this increase in size was sufficiently small compared with the indenter radius that it had only a minor influence a t an early stage of the indentation measurements. The implanted Ti was in the carbide state of TiC. The hardness and elastic modulus were in creased by approx. 2.5- and 3.5-fold due to the modification in struct ure by ion implantation. (C) 1998 Elsevier Science S.A.