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The European Union's strategy is to promote health in a population with an elevated life expectancy, together with the necessity of reducing healthcare costs, forces the development of titanium alloys and surface treatments that increase the implants life cycle and reduce hospitalization times. Beta titanium alloys with a nanoscale surface treatment are appointed as a viable alternative to improve the current prostheses biocompatibility. The elastic modulus reduction, through the incorporation of a high content of refractory elements, improves bone-prothesis mechanical compatibility and decrease bone resorption effect that causes the prosthesis failure after long implantation periods. The anodic oxidation processes are focusing the interest researchers, in the surface treatment field, because they enable a nanotubular topography on titanium alloys surfaces. This surface treatment increases the specific surface area, modifies the chemical composition and crystalline phase of the oxides present in the surface, these changes has an influence on the corrosion resistance and ions release of titanium alloys. These factors modify cell growth and differentiation rate, accelerating the bone regeneration process and improving, in the short and long term, implant osseointegration rate. In this Doctoral Thesis, the development of the electrochemical anodizing process is proposed to obtain a nanotubular coating in beta titanium alloys. The main objective is the characterization of the surface treatment, which presents a nanotubular topography, in β titanium alloys for biomedical applications. The maximum sintering temperature and the niobium powder particle size influence has been evaluated on the porosity, microstructure and mechanical properties for powder metallurgical Ti35Nb10Ta alloys. The morphology, chemical composition, crystalline structure, roughness, wettability, and corrosion resistance have been studied for the nanotubular surface treatment obtained in powder metallurgical beta alloy. This same study has been replicated for the biomedical Ti6Al4V ELI casting alloy. The objective has been to compare the results obtained in the powder metallurgical alloy with a titanium alloy currently used to manufacture implants. For the microstructural characterization the optical microscopy, scanning electron microscopy, X-ray dispersive energy spectroscopy, X-ray diffraction, and an infrared detection system have been used to determine the residual porosity, phase distribution, chemical homogeneity, identify the phases and quantify the oxygen content present in the Ti35Nb10Ta powder metallurgical alloy. The microstructural study for the surface treatment with nanotubular morphology was carried out using field emission scanning electron microscopy, Xray scattering energy spectroscopy, X-ray diffraction, and electron transmission microscopy. Efecto del anodizado electroquímico en la obtención de nanotubos en la superficie de aleaciones beta de titanio The effect of the electrochemical anodizing process, employed to obtain the nanotubular topography, on the surface roughness was evaluated using a confocal microscope. The wettability for different surface finishes was evaluated using an optical goniometer. The contact angle measurements, for different standard liquids, has allowed the calculation of surface free energy for different surface treatments. The electrochemical characterization, through OCP / EIS / potentiodynamic tests using a 1M NaCl solution, has allowed obtaining the titanium alloys corrosion resistance depending on their surface treatment and their nature. The results show that the particle size reduction on refractory powders and higher maximum sintering temperature reduce the residual porosity and increase the mechanical properties of Ti35Nb10Ta powder metallurgical alloy. The electrochemical anodizing process, using the electrolyte composed of 1M H3PO4 and 0.8% w.t NaF, is capable of obtaining a nanotubular topography in the Ti35Nb10Ta alloy. Heat treatment cycle, after the anodizing process, reduces the fluorine content present in the nanotubular oxide layer and stabilizes the titanium oxide crystalline structure on the powder metallurgy β titanium alloys. The electrochemical anodization process, to obtain a nanotubular layer in Ti35Nb10Ta alloys, increases the surface roughness. Nanotubular topography increases the contact angle and surface free energy of titanium alloys. The ultraviolet light irradiation modifies the nanotubular titanium surfaces behavior from hydrophobic to hydrophilic. The corrosion resistance for nanotubular surfaces, without heat treatment, is lower than the rest of the surface treatments studied due to its increase in relative surface area. The heat treatment carried out on the nanotubular surfaces stabilizes the titanium oxide crystalline phases (anatase and rutile) and increases titanium alloys corrosion resistance. Finally, in order to introduce the powder metallurgy and the nanotubular surface treatment in biomedical applications, it is necessary to continue researching in subprocesses that will improve the chemical/microstructural homogeneity, the mechanical properties, and corrosion resistance, as well as quantify the degree of biocompatibility improvement on this new surface treatments. Efecto del anodizado electroquímico en la obtención de nanotubos en la superficie de aleaciones beta de titanio I Contenido Capítulo 1: Introducción1 1.1 Introducción  3 1.1.1 El envejecimiento de la población y la necesidad de nuevos biomateriales  4 1.1.2 Diseño de prótesis en función de las necesidades del paciente  7 1.1.3 Justificación tratamientos superficiales en los Biomateriales  9 1.1.4 Desarrollo de aleaciones beta de titanio para su empleo como biomateriales  11 1.2 Motivación  13 1.3 Objetivos  14 1.4 Aportaciones de la investigación  15 Capítulo 2: Antecedentes científicos17 2.1 El titanio como biomaterial  19 2.2 Evolución de las aleaciones de titanio  22 2.3 Desarrollo de tratamientos superficiales para incrementar la tasa de osteointegración .... 23 2.3.1 Proyección térmica  25 2.3.2 Arenado  25 2.3.3 Grabado ácido  26 2.3.4 Oxidación electroquímica en electrolitos que presentan iones de flúor  29 2.3.4.1 Oxidación electroquímica: Formación de nanotubos  30 2.3.4.2 Oxidación electroquímica: Control de las dimensiones de los nanotubos  32 2.3.4.3 Oxidación electroquímica: Modificación de la estructura cristalina de los nanotubos  34 2.3.4.4 Oxidación electroquímica: Mejora del grado de biocompatibilidad de los nanotubos  34 2.4 Desarrollo de recubrimientos bioactivos para incrementar la tasa de osteointegración .... 35 2.4.1 Recubrimientos bioactivos de hidroxiopatita y fosfato de calcio realizados en nanotubos  37 2.4.2 Recubrimientos antibacterianos realizados en nanotubos  37 Capítulo 3: Planificación de la investigación40 3. Planificación de la investigación  43 3.1 Fase 1: Diseño y fabricación de las aleaciones pulvimetalúrgicas β de titanio  44 3.1.1 Tecnología de fabricación empleada  44 3.1.2 Selección de los parámetros de fabricación pulvimetalúrgicos  45 Efecto del anodizado electroquímico en la obtención de nanotubos en la superficie de aleaciones beta de titanio II 3.1.3 Formulación de las aleaciones β pulvimetalúrgicas  45 3.1.4 Sinterizado de las aleaciones β pulvimetalúrgicas  46 3.1.5 Sinteribilidad de los polvos  47 Densidad mediante la técnica de Arquímedes 48 3.2 Etapa 1.1: Caracterización mecánica de las aleaciones pulvimetalúrgicas β de titanio 51 3.2.1 Ensayos de Flexión  51 3.2.2 Determinación del módulo elástico por ultrasonidos