Thin Solid Films 426 (2003) 271–280 0040-6090/03/$ - see front matter  2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0040-6090(03)00002-6 Fretting maps for anodised aluminium alloys K. Elleuch *, S. Fouvry , Ph. Kapsa a, b b Laboratoire des systemes electromecaniques, Ecole Nationale d’Ingenieurs de Sfax, Sfax, Tunisia a ` ´ ´ ´ Laboratoire de tribologie et dynamique des systemes, Ecole Centrale de Lyon, Ecully, France b ` Received 23 July 2002; received in revised form 21 December 2002; accepted 23 December 2002 Abstract In this work, fretting maps of various surface modifications were established based on sliding transition criteria. Analyses of bulk material fretting maps are performed as a reference. It was found that anodising treatments induce shifts of all sliding domains especially the one relative to the mixed regime. The fretting fatigue resistance of the coatings was analysed according to the features of the fretting maps of the coatings. The results confirm that fretting maps of materials are effective tools to predict the fretting fatigue properties of substrates and surface-modification coatings. In addition, impact of friction coefficient and correlation with sliding transition is discussed.  2003 Elsevier Science B.V. All rights reserved. Keywords: Fretting maps; Aluminium alloy; Anodic oxidation; Tribology 1. Introduction Contacting components submitted to vibrations may be affected by wear or fatigue induced cracking. These phenomena, generally known as fretting, have been studied for many years using various simulation tests. Significant progress was obtained in the study of fretting parameters when fretting maps were introduced. It was Vingsbo and Soderberg w1x who first introduced a new ¨ approach to representing and classifying experimental fretting data: fretting maps—a diagram showing the relevant regimes in two variables (e.g. displacement, amplitude and frequency), with regime boundaries rep- resenting critical values for the transition from one to another. Three fretting regimes will be considered here (Fig. 1): 1. the partial slip regime (PSR) is defined from Q – D cycles remaining closed to a coarse damage initiation characterised by a decrease in the contact stiffness or in the Q – D initial slope. It is a quasi-non-dissipative regime; 2. the gross slip regime (GSR) is characterised by cycles that remain quasi-rectangular but for which possible *Corresponding author. Departement de Genie des Materiaux, ´ ´ ´ Ecole Nationale d’Ingenieurs de Sfax, BP. W, 3038 Sfax, Tunisia. ´ Tel.: q216-74-274-088; fax: q216-74-275-595. E-mail address: khaled.elleuch@ec-lyon.fr (K. Elleuch). strong variation of the maximum tangential force can be obtained at the end of the cycle; 3. a mixed slip regime (MSR) is a fretting regime characterised by a complex shape for the friction log. Closed, quasi-rectangular and very often elliptic cycles generally appear after some time. Later, Vincent et al. w2x established the running conditions fretting map (RCFM) and the material response fretting map (MRFM) to successfully explain the fretting mechanism of different types of fretting damage. The fretting process of materials can be described dynamically according to these fretting maps w3x. Accordingly, the fretting damage behaviour of sev- eral materials, such as aluminium alloy, iron-based alloy and titanium alloy, by using fretting maps have been investigated w4–6x. In general, the PSR, MSR and GSR in the RCFM correspond to the no degradation, cracking and particle detachment domains in the MRFM, respectively. In recent years, surface modification has been suc- cessfully applied as an effective method to improve the wear resistance properties of materials and to enhance the ability of components to resist fretting damage w7– 10x. However, so far, no fretting maps have been established that incorporate surface-modification coat- ings because of the complexity of the fretting behaviour of surface coatings w11x. The fretting maps of various