Synthesis and Thermal Treatment of Hydroxyapatite Doped with Magnesium, Zinc and Silicon

Pure nano-crystalline hydroxyapatite (Hap) and Hap doped with magnesium, zinc and silicon, namely Hap-0.25wt%Mg: Hap01, Hap-0.25wt%Mg-0.47wt%Si: Hap02, Hap-1.50wt%Mg-0.47wt%Si: Hap03, Hap-0.67wt%Mg-0.2wt%Zn-0.13wt%Si: Hap04, were synthesized using aqueous precipitation method. The pure and doped Hap were calcined individually at 400, 650 and 850 C for 2h, and investigated by Brunauer-Emmett-Teller (BET) specific surface area and porosity measurements, as well as by X-ray powder diffraction (XRD). The morphology and particle size of nano-crystalline powders were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal stability of the obtained nanoceramics from 30 C to 1000 C and the effect of calcination temperatures (400, 650 and 850 C) on their composition and structure were also determined by using TG, DTG, TGA and DTA techniques coupled with SEM-EDX. Results analysis shows a high thermal stability (up to 1000 C) of these nanomaterials, including the triple-substituted Hap with Mg, Zn and Si (Hap04). Simultaneous incorporation of Mg, Zn and Si into Hap lattice represents a novelty and promotes a new generation of synthetic porous nanoceramics with unique Hap structure, and high thermal stability. Due to their chemical composition and structure rather similar to those characteristic for the inorganic component of bone, these nanoceramics can have multiple applications in biomedicine, as bone substitutes, for metal coatings and in drug delivery systems.