In simulated body fluid performance of polymorphic apatite coatings synthesized by pulsed electrodeposition

Surface modification is to modify biological responses through changing surface properties without reducing the mechanical properties of the implant. Specifically bioactive coatings, such as hydroxyapatite, carbonate apatite and dicalcium phosphate dehydrate, have been deposited on carbon/carbon (C/C) composites to change the bio-inert surface state. This work focused on the effects of voltages and electrolyte concentrations of pulsed electrodeposition on apatite layer. The apatite coatings thus synthesized were then structurally, morphologically and chemically characterized using X-ray diffraction, scanning electron microscopy, Transmission electron microscopy and Fourier-transform infrared spectroscopy. Remarkably, the voltages and electrolyte concentrations changed the structure, morphology and crystallinity of the obtained coatings. In vitro bioactivity evaluation of polymorphic apatite coatings was performed by soaking the apatite layer coated C/C composites in simulated body fluid (SBF). The corrosion behavior was investigated via the potentiodynamic polarization test in SBF solution. The results confirmed that the increasing deposition voltage and concentration of electrolyte resulted in promoting bioactivity and corrosion resistance by altering the morphologies and phases.