Proceedings of SerbiaTrib '13

Serbian TribologySocietySERBIATRIB ‘1313 th International Conference onTribologyKragujevac, Serbia, 15 – 17 May 2013Faculty of Engineeringin KragujevacTHE POTENTIAL OF MAGNESIUM ALLOYS ASBIOABSORBABLE / BIODEGRADABLE IMPLANTS FORBIOMEDICAL APPLICATIONSFatima Zivic 1 , Nenad Grujovic 1 , Geetha Manivasagam 2 , Caroline Richard 3 , Jessem Landoulsi 4 ,Vojislav Petrovic 51 Faculty of Engineering, University of Kragujevac, Serbia, zivic@kg.ac.rs, gruja@kg.ac.rs2 Vellore Institute of Technology, Centre for Materials Engineering, Tamil Nadu, India, geethamanivasagam@vit.ac.in3 François Rabelais University of Tours, Laboratory of Mechanics and Rheology, EA 2640-France, caroline.richard@univ-tours.fr4 Pierre & Marie Curie University of Paris, Laboratory of Surface Reactivity, UMR 7197-France, jessem.landoulsi@upmc.fr5 AIMME - Instituto Tecnológico Metalmecánico, Unidad de Ingeniería de Producto, Valencia, Spain, vpetrovic@aimme.esAbstract: The potential of magnesium alloys as bioabsorbable / biodegradable implants for biomedicalapplications has been extensively studied as emerging direction. This paper gives a review of current topicsin this field. Research activities related to biomedical magnesium alloys have been pursued in two maindirections, orthopedic and cardiovascular implants, by investigating different aspects of alloying systemdesign, novel structures, degradation rate control, and surface modification methods. Magnesium alloys arecurrently considered for applications as load-bearing implant devices such as plates, screws and pins forrepairing bone fracture. Highly important direction of research is degradable coronary stents. Degradablevessel stents promote stable vessel regeneration, unlike permanent stents. Different combinations of alloyingelements have been investigated in order to decrease corrosion rate.Tribological issues are also importantfor understanding of different phenomenon related to prolongation of Mg alloys corrosion degradationtime/rate, such as tribocorrosion, corrosion fatigue, and fatigue crack growth behavior.Keywords: Mg alloys, Bioabsorbable / Biodegradable implants.1. INTRODUCTIONThe beginning of the resorbable implantsconcepts is related to using polymers withcontrolled dissolution rates: polylactides andpolyglycolides, back in 1970s [1]. But the problemassociated with use of polymers is their mechanicalproperties, where metals have better characteristicsand represent the promising field for advancements.The history of biodegradable magnesium (Mg)implants started shortly after the discovery ofelemental magnesium by Sir Humphrey Davy in1808 [2]. It is supposed that the pure magnesiumwires were used as ligatures to stop bleedingvessels of three human patients in 1878 [2]. Theyelaborated corrosion induced degradation propertiesof pure magnesium and concluded that corrosionrate depended on the wire size. From those firstattempts, many other solutions and ideas were tried,because magnesium has been recognised as thepromising material for efficient degradableimplants. Today, in vitro and in vivo study dataexists, as well as some clinical trials data, but not soextensively present as for other biomedical metalmaterials, because degradable materials and Mgalloys are still having many unresolved issues ifcompared to the development of Ti biomedicalalloys. Even today, several important drawbacks ofthe technology and material need to be resolvedbefore its wide application in clinical practice.Magnesium is the seventh most abundantelement in earth’s crust (2% of the total mass) andalso essential and major constituent element ofhuman body, nontoxic and biocompatibleaccordingly [3]. It belongs to the group of alkalineearth metals and cannot be found in elemental formin nature, but only in chemical combinations, sincebeing highly reactive. From aspects of the Mgalloys production, important mineral forms are:magnesite MgCO3 (27% Mg), dolomite92 13 th International Conference on Tribology – Serbiatrib’13