Synthesis and characterization of sintered hydroxyapatite/lignin coatings on titanium

In order to improve corrosion stability and biocompatibility of titanium surfaces, hydroxyapatite (Ca10(PO4)6(OH)2, HAP) has been used as coating material due to the fact that it possess similar chemical composition as bone tissue. Lignin’s (Lig) usage in medical applications could be interesting because it could lead to thermal stability, hydrophilicity, biocompatibility and biodegradability of different materials. Bioceramic hydroxyapatite/lignin (HAP/Lig) coatings on titanium were obtained from ethanol suspension by electrophoretic deposition method. The uniform and compact HAP/Lig coatings were deposited at constant voltage of 60 V for 45 s and sintered at 900°C in argon atmosphere. The corrosion stability of sintered HAP/Lig coatings in simulated body fluid (SBF) at 37°C was investigated by open circuit potential-time measurements and electrochemical impedance spectroscopy (EIS). The greater values of open circuit potential, as well as EIS results, indicated improved corrosion resistance and good corrosion stability of HAP/Lig coatings in simulated body fluid at 37°C .