Mechanical and tribological properties of carbon and nitrogen consecutive ion implantation into aluminium

Mechanical and tribological properties of successive C and N ion implantation into Al were studied in the present work. Ion sequence, substrate temperature and subsequent thermal treatment were performed in order to understand the involved mechanisms on the surface hardening. The results showed that independent of the ion sequence, a higher surface hardness is obtained for room temperature ion implantation (≈ 10 GPa). At high substrate temperature the hardness decreases to 7 GPa. The hardening mechanisms are discussed in terms of: solid solution, hard embedded precipitates in the soft Al matrix and the damage produced by the ion implantation process. Adhesive and abrasive regimes are identified from the friction coefficient profiles and are function of the ion implantation parameters. Wear resistance is improved if subsequent thermal treatment at high temperature is performed. Wear improvement is correlated to the presence of a high concentration of carbon clusters in the Al matrix.