Title of article :
Degradation characteristics of hydroxyapatite coatings on orthopaedic TiAlV in simulated physiological media investigated by electrochemical impedance spectroscopy
Author/Authors :
Ricardo M. Souto، نويسنده , , Mar?a M. Laz، نويسنده , , Rui L. Reis، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2003
Abstract :
This paper concentrates on the degradation characteristics of hydroxyapatite (HA) coatings on orthopaedic Ti–6Al–4V alloy while immersed in Ringerʹs salt solution, which were investigated by electrochemical impedance spectroscopy. Electrochemical impedance spectroscopy measurements were used to in situ characterize the electrochemical behavior of the passivated alloy covered with HA during aging in Ringerʹs solution. Comparison of the electrochemical data for the coated material with that for the uncoated metal substrate was also performed. The characteristic feature that describes the electrochemical behavior of the coated material is the coexistence of large areas of the coating itself with pores where the substrate is exposed to the aggressive media. The interpretation of results was thus performed in terms of a two-layer model of the film, in which the precipitation of hydrated oxide or phosphate compounds seals the pores left by the ceramic coating. The blocking effect due to salt precipitation inside the pores produces an enhancement of the resistance values, thus effectively diminishing the metal ion release in the system.
Keywords :
Biomaterials , Corrosion resistance , Ti–6Al–4V , Hydroxyapatite , electrochemical impedance spectroscopy , Plasma-sprayed coatings
Journal title :
Biomaterials
Journal title :
Biomaterials