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- Ng, B. S., et al.
(författare)
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Characterisation of a duplex TiO2/CaP coating on Ti6Al4V for hard tissue replacement
- 2005
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 26:10, s. 1087-1095
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Tidskriftsartikel (refereegranskat)abstract
- An initial TiO2 coating was applied on Ti6Al4V by electrochemical anodisation in two dissimilar electrolytes. The secondary calcium phosphate (CaP) coating was subsequently applied by immersing the substrates in a simulated body fluid (SBF) with three times concentration (SBF×3), mimicking biomineralisation of biological bone. Electrochemical impedance spectroscopy and potentiodynamic polarisation assessments in SBF revealed that the anodic TiO2 layer is compact, exhibiting up to four-folds improvement in in vitro corrosion resistance over unanodised Ti6Al4V. X-ray photoelectron spectroscopy analysis indicates that the anodic Ti oxide is thicker than air-formed ones with a mixture of TiO2-x compound between the TiO2/Ti interfaces. The morphology of the dense CaP film formed, when observed using scanning electron microscopy, is made up of linked globules 0.1-0.5ÎŒm in diameter without observable delamination. Fourier transform infrared spectrometry with an attenuated total internal reflection analysis revealed that this film is an amorphous/poorly crystallised calcium-deficient-carbonated CaP system. The calculated Ca:P ratios of all samples (1.14-1.28) are lower than stoichiometric hydroxyapatite (1.67). These results show that a duplex coating consisting of (1) a compact TiO2 with enhanced in vitro corrosion resistance and (2) bone-like apatite coating can be applied on Ti6Al4V by anodisation and subsequent immersion in SBF. © 2004 Elsevier Ltd. All rights reserved.
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