CoCrMo biomedical alloys are used in the design of total or partial hip and knee joints due to their biocompatibility and their good mechanical properties such as high corrosion and wear resistance. The biomaterial surface spontaneously reacts with the environment forming a passive film of metallic oxides which protects the alloy from the medium and determines its corrosion behaviour.  The physiological media are one of the most aggressive electrolytes which enhance the corrosion process. This process contributes to metallic ions release into the human body and accelerates the degradation of these prostheses generating clinical problems in the patients. 
In this panorama, the present Doctoral Thesis aims to study the biocorrosion mechanisms of the CoCrMo alloy degradation under physiological conditions.
For this, the electrochemical characterization of the biomaterial under different physico-chemical conditions with biological relevance has been carried out (chemical composition of the simulated body fluid, pH, oxygen content and applied potential) which noticeably influences the electrochemical reactions occurring at the biomaterial/media interface. Subsequently, the influence of the albumin adsorption (model and main protein in the human body) on the electrochemical behaviour of the alloy depending on the protein concentration and temperature of the medium has been studied. This adsorption study has been carried out from the thermodynamic point of view and it was observed that the protein adsorption process onto the CoCrMo alloy surface occurs spontaneously by chemisorption and can be modelled by the Langmuir Isotherm.  Finally, the passivation and the protein adsorption kinetics have been studied by an electrochemical quartz crystal microbalance applied used on a CoCrMo alloy at 37ºC and by ex-situ surface analysis. The complementary use of both techniques allows quantifying the amount of metallic cations released from the material to the physiological medium as well as the properties of the passive film (chemical composition and thickness).
With all these results, it has been observed that the CoCrMo passive dissolution critically depends on the electrochemical potential and the electrolyte properties (temperature and chemical composition). 
The results obtained in the present Doctoral Thesis are the first step to analyse the behaviour of the CoCrMo biomedical alloy under more realistic conditions involving corrosion and wear phenomena (tribocorrosion phenomena).