Investigation of the Pore Morphology of the Hydroxyapatite-Based Bicomposites Processed by Two Step Sintering

摘要

The porous hydroxyapatite(HAp)-based biocomposites were prepared through powder metallurgy technology combined with pore forming technique.The current research focuses on the pore morphology characterization of the porous biocomposites based on the submicronic HAp powders.Three types of foaming agents were used for generation of pores in the ceramic matrix: titanium hydride(TiH2),ammonium hydrogen carbonate(NH4HCO3)and calcium carbonate(CaCOa).Besides the foaming agent role,the titanium hydride ensures increasing of the mechanical strength and flexibility of the HAp matrix.The effects of TiH2,NH4HCO3 and CaCO3 on porous biocomposites in terms of porosity and pore connectivity were systematically investigated.The pore characteristics of the HAp-based specimens were characterized by macroscopic analysis and scanning electron microscopy(SEM).The results show that the total porosity of the biocomposites can be tailored successfully by changing the amount of the foaming agents.Varying the amount of TiH2,NH4HCO3 and CaCO3 the total porosity values range between 36 and 40%.Furthermore,this combination of fabrication techniques allowed the formation of interconnected pores with two levels of pore size: micropores with dimensions smaller than 25 μm and macropores with dimensions ranging between 300 μm and 700 μm.