Ceramics-Silikáty 50 (3) 153-158 (2006)

THE CALCIUM PHOSPHATE FORMATION ON TI ALLOY BY PRECALCIFICATION PROCESS AT STATIC CONDITIONS

R. Horváthová, D. Rohanová, A. Helebrant

The aim of this paper was to study the influence of precalcification process on the nucleation as well as growth of calcium-phosphates crystals (Ca-P) on the surface of Ti alloy. Ti alloy was precalcified by the calcification solutions (SCS1-3) with different content of Ca²⁺ and (PO4)^3- ions and compared with the non-precalcified sample. The results of Ca²⁺ and (PO4)^3- analysis indicate that precalcification step accelerates the consumption of both Ca²⁺ and (PO4)^3- ions from simulated body fluid (SBF) solution. The deposition of Ca-P phase was completed approximately 6 days earlier when compared it with the non-treated samples. Analytical measurements as well as the surface observation enable to find optimal calcification solution marked as SCS2 containing (mmol/dm³) 4.0 Na⁺, 5.0 Ca²⁺, 10.0 Cl^-, 2.5 H₂PO₄^- and 1.5 HCO₃^-. The influence of S/V ratio (surface area / volume of soaking media) changes on the nucleation and thickness of Ca-P layer formed in the SCS2 solution has been studied in the second part of this work. It was found out that 4 days immersion in SCS2 solution at S/V ratios at 0.1 and 0.5 cm^-1, respectively, is enough time for complete deposition by Ca-P phase on the alloy surface. The changes of the S/V ratio allow adjusting the thickness of Ca-P layer on the surface.

Keywords: Precalcification, Calcium phosphate, Titanium alloy (Ti-6Al-4V), Hydroxyapatite, Biomimetic process