Available online at www.sciencedirect.com Wear 264 (2008) 893–898 Nanomechanical and nanowear properties of Cr 3 C 2 thin films deposited by rf sputtering A. Jellad a,∗ , S. Labdi a , C. Malibert a,b , G. Renou a a Laboratoire d’´ etudes des Milieux Nanom´ etriques, Universit´ e d’Evry Val d’Essonne, bˆ atiment Maupertuis, bd F. Mitterand, 91025 Evry Cedex, France b Laboratoire Structures, Propri´ et´ es et Mod´ elisation des solides, Ecole Centrale de Paris, grande voie des vignes, 92295 Chˆ atenay-Malabry Cedex, France Accepted 13 February 2007 Available online 26 June 2007 Abstract In this investigation, nanoindentation, nanoscratch and nanowear tests were done in order to study the nanomechanical and nanotribological properties of the chromium carbide nanostructured thin films. Chromium carbide films were synthesized by rf sputtering from a Cr 3 C 2 target on magnesium oxide substrate. The samples were characterized by X-ray diffraction and grazing X-ray reflectivity. All the films have a thickness of 300 nm. A pyramidal Berkovich indenter diamond tip was used for nanomechanical testing. The residual wear depth of the samples was examined using an atomic force microscope (AFM). In this study, an experimental method adapted to the nanowear properties was explored. We have studied the influence of the substrate temperature on the structural, mechanical and tribological properties of chromium carbide films. We have shown that Cr 3 C 2 films deposited at a substrate temperature up to 600 ◦ C exhibit a better wear resistance and a hardness value higher than what is measured in the case of the films deposited at room temperature. © 2007 Elsevier B.V. All rights reserved. Keywords: Friction; Nanoscratch; Nanowear; Thin films 1. Introduction During last years, nanostructured thin films have attracted considerable attention in several industrial applications [1]. More precisely, hard protective coatings of chromium car- bide show excellent physical properties such as high hardness, strength, toughness, chemical stability and corrosion resis- tance [2,3]. Because of these properties, they are widely used especially in tribological applications. Chromium carbide (Cr 3 C 2 ) is used as wear resistant and protective surface films in corrosive environments [4]. Therefore, there is a need for studying friction and wear properties of these coatings in the nanometer scale. For this purpose, nanomechanical testing is used in order to develop the understanding of several phys- ical phenomena such as cracking, deformation and adhesion. Nanoindentation and nanoscratch measurements are performed in order to determine mechanical and tribological properties ∗ Corresponding author. Tel.: +33 1 69 47 76 70; fax: +33 1 69 47 76 31. E-mail address: asma.jellad@univ-evry.fr (A. Jellad). of Cr 3 C 2 films. A reciprocating nanowear test is used in order to detect the surface damage during the wear process [5]. The objective of this work was to study the nanotribological and nanowear properties of chromium carbide thin films. We have investigated the influence of directional tip geometry on nanowear measurements. The effect of the deposition substrate temperature on friction and wear properties of chromium carbide thin films was explored. 2. Experimental details 2.1. Samples deposition and characterization Chromium carbide films were deposited on MgO (1 0 0) sub- strate by cathodic rf sputtering technique in argon plasma. A stoichiometry pure Cr 3 C 2 target (99.99% purity) is used during the sputtering process. The total deposition pressure was fixed at 0.27 Pa and the working bias voltage was of about 300 V. The sputtering rate was around 0.023 nm s -1 . The deposition 0043-1648/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2007.02.026