Hydroxyapatite Deposited on Flat and porous Ti

Abstract-Formation of porous Ti layer during electrochemical etching in H₃PO₄ + NH₄F, subsequent deposition of calcium-phosphate and corrosion behavior of the materials was described. Anodic etching results in surface roughening with pits diameter in the range of 7-12 μm. The subsequent cathodic electrochemical treatment, results in hydroxyapatite (HA) deposition. The source of Ca and P were two types of electrolytes: 0.1M HCl + 0.005M HA and 0.042M Ca(NO₃)₂ + 0.025M (NH₄)₂HPO₄ + 0.1M HCl. The formed HA layer has lamellas structure. The deposited calcium-phosphate layer could be useful for the osseointegration and presents excellent corrosion resistance in simulated body fluids. The corrosion current Ic for flat Ti, porous Ti and porous Ti with HA layer is: 3.9·10^-8 A·cm^-2, 2.52·10^-8 A·cm^-2 and 1.07·10^-8 A·cm^-2 respectively. It was found, that anodization and subsequent calcium-phosphate deposition, results in better corrosion resistance of the samples, with comparison to the sample without these treatments.