title: Friction and solid-solid adhesion on complex metallic alloys.
abstract: The discovery in 1987 of stable quasicrystals in the Al-Cu-Fe system was soon exploited to patent specific coatings that showed reduced friction in ambient air against hard antagonists. Henceforth, it was possible to develop a number of applications, potential or commercially exploited to date, that will be alluded to in this topical review. A deeper understanding of the characteristics of complex metallic alloys (CMAs) may explain why material made of metals like Al, Cu and Fe offers reduced friction; low solid-solid adhesion came later. It is linked to the surface energy being significantly lower on those materials, in which translational symmetry has become a weak property, that is determined by the depth of the pseudo-gap at the Fermi energy. As a result, friction is anisotropic in CMAs that builds up according to the translation symmetry along one direction, but is aperiodic along the other two directions. A review is given in this article of the most salient data found along these lines during the past two decades or so.
authors.affiliation: Institut Jean Lamour, UMR 7198 CNRS Université de Lorraine, Parc de Saurupt, CS 50840, 54011 Nancy, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Dubois
authors.affiliation: Laboratoire de Chimie Physique, Matière et Rayonnement UMR 7614 CNRS Sorbonne Universités UPMC Univ. Paris 06, 11 rue P et M Curie, 75005 Paris, France.
authors.forename: Esther
authors.initials: E
authors.lastname: Belin-Ferré
keywords: adhesion; composites; fretting; friction; surface energy; tribology