The addition of nanomaterials, such as graphene and graphene oxide, can improve the mechanical properties of hydroxyapatite (HA) nanocomposites (NCPs). However, both the dispersive state of the starting materials and the sintering process play central roles in improving the mechanical properties of the final HA NCPs. Herein, we studied the mechanical properties of a reduced graphene oxide (r-GO)/HA NCP, for which an ultra-high shear force was used to achieve a nano-sized mixture through the dispersion of r-GO. A low-temperature, short-duration spark plasma sintering (SPS) process was used to realize high-density, non-decomposing r-GO/HA NCPs with an improved fracture toughness of 97.8% via the addition of 0.5 wt.% r-GO. Greater quantities of r-GO improve the hardness and the fracture strength. The improved mechanical properties of r-GO/HA NCPs suggest their future applicability in biomedical engineering, including use as sintered bodies in dentistry, plasma spray-coatings for metal surfaces, and materials for 3D printing in orthopedics.
Keywords: graphene oxide; hydroxyapatite; mechanical property; nanocomposite; spark plasma sintering; ultra-high shear force.