Determination of Mechanical Properties and Physical Characterization of HA-ZnO-\( {\mathbf{Fe}}_{3} {\mathbf{O}}_{4} \) Composites for Implant Applications

The high biocompatibility of Hydroxyapatite (HA) makes it one of the most common ceramics used in bio-implants. However, its inferior mechanical properties can be improved through the formation of composites. In the present work, composites are fabricated by adding ZnO and Fe₃O₄ in HA through compaction and sintering in five different compositions to study their effect on HA. Their structural properties using scanning electron microscopy and x-ray diffraction are studied, while mechanical properties are studied using micro-hardness test and compression test. In experimental results, it was observed that 7.5% ZnO in HA has resulted in improved relative density (~ 99%), increased hardness (6.9 GPa) but with reduced compressive strength (25.6 MPa), hence it can be suitable for hard coatings on bio-implants. 20% porosity was observed in an HA-7.5%ZnO-20%\( Fe_{3} O_{4} \) composite with compressive strength (40 MPa) and hardness (4.1 GPa). Among all, this composition showed a maximum balance between mechanical properties and porosity.