Preparation and Characterization of Hydroxyapatite – Zirconia Composite

Abstract

In this present study, sintered hydroxylapatite-zirconia composites were processed and characterized. Hydroxylapatite and both undoped and doped zirconia powders were synthesized using precipitation method. To synthesize partially stabilized zirconia (PSZ) and tetragonal stabilized zirconia (TZP) 2.5 mol% and 7.5 mol% of Ca2+ were added to precursor material for zirconia synthesis. Though HA powders showed the presence phase pure hydroxyapatite a mixture of monoclinic and tetragonal zirconia phases were observed in undoped zirconia, PSZ and TZP powders. Zirconia was added to the extent of 5, 10 and 15 wt% to HA powder and consolidated into pellets and sintered at 1250oC to prepare HA-ZA, HA-PSZ and HA-TZP composite. XRD study of sintered composites showed the presence of tricalcium phosphate (TCP) as a result of decomposition of HA at 1250°C in presence of zirconia. HA-5 wt% ZA composition showed the highest bulk density, Vickers hardness and bi axial flexural strength. This study shows that mechanical strength of HA can be improved after addition of both stabilized and unstabilized zirconia and HA-ZrO2 based composite orthopedic implant can be used in moderately load bearing applications where sole hydroxyapatite implant may fail.