Understanding phase stability, microstructure development and biocompatibility in calcium phosphate-titania composites, synthesized from hydroxyapatite and titanium powder mix

Some important issues in developing Calcium phosphate (CaP)-based composites are the thermo-chemical compatibility, dissociation and its influence on microstructure development as well as on biocompatibility property. In the present work, a planned set of sintering experiments have been carried out for different Hydroxyapatite (HAp, one of the materials in CaP group)-Titanium(Ti) starting powder mix (10-40 wt.% Ti) in the temperature range of 1000-1400 deg. C under air atmosphere. In all the sintered samples, β-tricalcium phosphate (β-TCP) and rutile (TiO2) are the major crystalline phases irrespective of the sintering temperature; while other reaction products, like, CaTiO3, CaO are also recorded for various HAp-Ti compositions. Based on the combined study of XRD, FT-IR, TGA and thermodynamic analysis, the feasibility of various possible sintering reactions are discussed. Based on SEM-EDS analysis, the microstructure development has been described in terms of matrix constituents of TCP/HAp phase, agglomerated TiO2 grains and the presence of pores. The results of the cell culture experiments involving L929 mouse fibroblast cells reveal excellent bioactivity property and in particular, good cell adhesion as well as cell-cell interaction