Effect of ZrO 2 , TiO 2 , and Al 2 O 3 Additions on Process and Kinetics of Bonelike Apatite Formation on Sintered Natural Hydroxyapatite Surfaces

In this study, the ability to form bone‐like apatite on surface of both pure natural hydroxapatite ( N ‐ HA ) and natural hydroxyapatite containing 5 wt% of ZrO 2 or TiO 2 or Al 2 O 3 , sintered at 1300°C for 2 h and soaked in the simulated body fluid for different times, was studied. It has been found that the presence of β‐tricalcium phosphate in N ‐ HA + 5 wt% ZrO 2 or TiO 2 has promoted the precipitation of bone‐like apatite in the Zr or Ti poorest regions. By contrast, the presence of 5 wt% of Al 2 O 3 did not induce any apatite precipitation on N ‐ HA sample surfaces.