RT Journal Article T1 Carbon layers formed on steel and Ti alloys after ion implantation of C+ at very high doses A1 Viviente, J. L. A1 Garcia, A. A1 Loinaz, A. A1 Alonso, F. A1 Oñate, J. I. AB Ion implantation is a useful technique to tailor surface properties of steel and Ti alloys. In particular, very high dose C+ implantation (in the range of 1018 ions cm-2) offers the possibility of forming carbon layers without a sharp interface with the substrate material. In this study, ion implantation of carbon doses up to 8 × 1018 ions cm-2 has been performed on 440C martensitic stainless steel and Ti6A14V substrates under similar conditions and tribological and surface analysis results have been compared. Surface hardening occurred for all ion implantation conditions up to doses of 1018 ions cm-2 [1-3]. Higher doses resulted in a different behaviour for both materials. The stainless steel showed a softening while a twofold hardness increase was maintained in the Ti alloy. Nevertheless, at the higher implanted dose a decrease in hardness was also observed in the Ti alloy. Small area XPS analyses were performed to evaluate the chemical states after ion implantation and establish a relationship with the observed surface hardening. Depth profile XPS analyses showed that for a dose of 4 × 1018 ions cm-2 a carbon layer (with concentration over 85% at. C) was formed in the near surface region for both materials. SN 0042-207X YR 1999 FD 1999 LK https://hdl.handle.net/11556/4489 UL https://hdl.handle.net/11556/4489 LA eng NO Viviente , J L , Garcia , A , Loinaz , A , Alonso , F & Oñate , J I 1999 , ' Carbon layers formed on steel and Ti alloys after ion implantation of C + at very high doses ' , Vacuum , vol. 52 , no. 1-2 , pp. 141-146 . https://doi.org/10.1016/s0042-207x(98)00213-9 NO This work has been carried out with the financial support of the Spanish `Comisión Interministerial de Ciencia y Tecnologı́a' (CICYT) under Project Number MAT95-0980-C02-02. DS TECNALIA Publications RD 30 jul 2024