INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
New spray deposition technique for hybrid sol-gel coatings for applying onto stainless steel permanent implants
Autor/es:
SHEILA OMAR; JOSEFINA BALLARRE; SERGIO A. PELLICE; SILVIA M. CERÉ
Reunión:
Congreso; 8vo Congreso Latinoamericano de Organos Artificiales, Biomateriales e Ingeniería de Tejidos COLAOB 2014; 2014
Resumen:
The use of AISI 316L stainless steel as permanent implant in orthopedic surgery is conditioned due to its poor corrosion resistance in physiological fluids. This can be overcome by applying a hybrid organic-inorganic sol-gel coating. The traditional way to apply this kind of hybrid coating is by dipping which has the limitation to be used for simple or revolution symmetric shapes. The spray technique provides a way to improve the coating deposition, not only making it easier and able to coat complex geometries, but also being a promising technique for industrial application of the organic-inorganic thin films. The coating acts as a barrier for ion migration and simultaneously can be loaded with different kind of functional particles in order to improve the implant performance, regarding bone attachment and bioactivity. This work presents coatings made by the sol-gel method containing tetraethoxysilane (TEOS), methyl-triethoxysilane (MTES) and in some cases, 10% in mol of silica nanoparticles as precursors. The final silica concentration for both sols was 3.33 mol/L (or 200 g/L). Coatings were deposited on stainless steel AISI 316L sheets used as substrates previously polished, cleaned and degreased. After each layer deposition, a thermal treatment in air atmosphere at 350º for 30 min was carried out. The effect of adding silica nanoparticles can be noticed in the increment of the thickness without cracking. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves were used to evaluate the protectiveness of the coatings during time. A simulated body fluid (SBF) solution was used as electrolyte in all the experiments. The samples were immersed in SBF for 15 or 30 days, and maintained at 37 ºC in a sterilized furnace. Coatings were homogeneous when observed by microscopy and its surface and thickness was evaluated by profilometry, resulting similar before and after immersion in SBF. Moreover, after the immersion time the TEOS-MTES-SiO2 coating system presents lower current densities and higher impedance modulus than the bare substrate showing the protectiveness of the coating