Fabrication and properties of porous ZnO/hydroxyapatite biocomposites

The porous ZnO/hydroxyapatite (HA) biological composites were prepared by spark plasma sintering (SPS) technology. The effects of different nano ZnO contents on the microstructure, pore characteristics, mechanical properties, mineralization and degradation of the ZnO/HA composites were studied. The results show that the sintered ZnO/HA composites are mainly composed of HA phases and ZnO phases. With increasing of ZnO content, the porosity of the ZnO/HA composites increases slowly, the compressive strength decreases slowly, and the elastic modulus does not change much. The ZnO/HA composites have the porosity>40%, pore diameter of 50-500 μm, compressive strength>148 MPa, elastic modulus about 6.5 GPa, which can meet the requirements of bone repair materials. The mineralization and degradation experiments in simulated artificial body fluids show that a large number of osteoid apatite layers are formed on the surface of the ZnO/HA composite after soaking for 7 days. Furthermore, the apatite formation ability of the ZnO/HA composites is significantly enhanced and the degradation rate of the composites is increased with increasing of ZnO content.