Ta-based multilayer coating on Low Carbon content cobalt alloy for arthroprostheses 1 Tantalum-based multilayer coating on cobalt alloys in total hip and knee replacement C. Balagna a,* , M.G. Faga b , S. Spriano a a Materials Science and Chemical Engineering Department, Politecnico di Torino, Corso Duca degli Abruzzi 24,10129 Torino, Italy b Istituto di Scienza e Tecnologia dei Materiali Ceramici, Consiglio Nazionale delle Ricerche, Strada delle Cacce 73, 10135 Torino, Italy * Corresponding author: Tel.: +39 011 5644668; Fax : +39 011 5644699; E-mail address: [email protected] This is the author post-print version of an article published on Materials Science and Engineering: C, Vol. 32, pp. 887-895, 2012 (ISSN 0928-4931). The final publication is available at http://dx.doi.org/ 10.1016/j.msec.2012.02.007 This version does not contain journal formatting and may contain minor changes with respect to the published edition. The present version is accessible on PORTO, the Open Access Repository of the Politecnico of Torino, in compliance with the publisher’s copyright policy. Copyright owner: Elsevier. 2 Abstract Cobalt-chromium-molybdenum (CoCrMo) alloys are widely used in total hip and knee joint replacement, due to high mechanical properties and resistance to wear and corrosion. They are able to form efficient artificial joints by means of coupling metal-on-polymer or metal-on-metal contacts. However, a high concentration of stress and direct friction between surfaces leads to the formation of polyethylene wear debris and the release of toxic metal ions into the human body, limiting, as a consequence, the lifetime of implants. The aim of this research is a surface modification of CoCrMo alloys in order to improve their biocompatibility and to decrease the release of metal ions and polyethylene debris.