Electrodeposition of NaHAp coatings on CoNiCrMo alloys (NaHAp/CoNiCrMo) and their electrochemical behavior in simulated body fluids solution
Résumé
Sodium-hydroxyapatite coatings (NaHAp) were electrodeposited on the surface of CoNiCrMo alloys (NaHAp/CoNiCrMo) from an electrolyte solution containing Ca(NO3)2, NH4H2PO4 and NaNO3. The phase structure, composition and morphology of the coatings were studied by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) and Scanning electron microscopy (SEM). The results showed that the obtained coatings were single phase crystals of HAp, with plate shape and that the sodium acts as a doping element in their composition (0.73%). The deposition temperature affected the thickness as well as the phase structure of the coatings. When the deposition temperature increased, the thickness of the coating increased. The XRD results showed that the coating obtained at 50°C was composed of single phase crystals of HAp with the thickness 6.34m. The in vitro test with CoNiCrMo and NaHAp/CoNiCrMo materials in SBF solution was realized with different immersion times. The results showed that the pH of SBF decreased and the mass of materials increased. SEM images prove the formation of apatite on the surface of NaHAp/CoNiCrMo leading to the decrease of the corrosion current density during immersion process in SBF solution.