Deposition of Layered Bioceramic HA/TiO<sub>2 </sub>Coatings on Ti-6Al-7Nb Alloys Using Micro-Arc Oxidation

Abstract

Investigation results of HA/TiO2 bioceramics coating on the Ti-6Al-7Nb alloy by MAO process were presented. The voltages of 300-500 V. In the electrolyte solution contain (HA=6g/l, EDTA=3g/l, NaOH=8g/l, and KOH=1g/l) are used. The coating characteristics are identified by using field emission scanning electron microscopy (FESEM), (EDX), atomic force microscopy (AFM) and the resulted phases are identified by X-Ray diffraction (XRD), mechanical test (microhardness, and wear). The electrochemical test in the Ringer’s solution using a potentiodynamic polarization tests. The results of the tests showed the possibility of deposition of a composite nano ceramic layer was obtained from hydroxyapatite (HA) with TiO2 were observed with increased voltage increased thickness layer and concentration of HA and decreased porosity, The identical dependencies of changes of the coating thickness with increase voltage and time. The best results were obtained in terms of hardness (368.1HV) and wear resistance equal to (4.33×10-7) for 400V&15min. Improvement corrosion resistance equals (87.4%).