Nickel-incorporated amorphous carbon film deposited by femtosecond pulsed laser ablation

Metal-containing diamond-like carbon films (Me-DLC), with metallic particles embedded in a DLC matrix, have become good candidates to improve many film properties (including mechanical properties and adhesion) and to enhance the tribological behavior in severe conditions. Previous studies on the properties of Me-DLC coatings have reported lower compressive stresses and higher wear resistance compared to undoped DLC. In many cases, the presence of metal inclusions enhances adhesion on metallic substrates. The present study investigates the composition and nanostructure of DLC coating alloyed with 50 at.% concentration of nickel. The film is deposited by femtosecond pulsed laser ablation (PLD) by ablating sequentially graphite and nickel targets. The chemical composition and the bonding characteristics of this film are determined by X-ray Photoelectron Spectroscopy (XPS), Near Edge X-ray Absorption Spectroscopy (NEXAFS) and Electron Energy Loss Spectroscopy (EELS) imaging. The chemical composition, the carbon hybridization and the morphology of the a-C:Ni film at the microscopic scale are discussed, in relation to the thermodynamic phase diagram of the Ni-C system.