Characterization of hydroxyapatite-reduced graphene oxide nanocomposites consolidated via high frequency induction heat sintering method

In this study, a solvothermal method at the temperature of 180 °C for 4 h was used for the synthesis of hydroxyapatite-reduced graphene oxide (HA-rGO) nanopowders by employing the nitrogen gas injection. To synthesize the powders, a solvent containing dimethylformamide, anhydrous ethanol, diethylene glycol, and water was used (1:1:1:2, respectively). Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors, respectively. The synthesized powders were consolidated by a high-frequency induction heat sintering method. The powders and sintered samples were then evaluated using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, Vickers indentation technique, and biocompatibility assay. The findings of this study showed that the final powders synthesized by the solvothermal method had calcium to phosphate ratio of about 1.67. The high frequency induction heat sintering method was suitable for consolidating these powders and exhibited a higher relative density than other methods. The mechanical properties of the nanocomposite were higher than those of pure HA. In biological experiments the difference of HA effect in comparison with the nanocomposite was not significant and both were biocompatible.