Abstract
Hydroxyapatite-magnesium titanate composite nanopowders have been developed using a mechanothermal process. Thermal treatment of the milled powders at 700 °C resulted in the formation of HAp/MgTiO3-MgO nanocomposite. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) techniques were utilized to characterize the synthesized powders. The results revealed that the dominant phases after mechanical activation were hydroxyapatite, anatase (TiO2) and periclase (MgO); while after thermal annealing process at 700 °C, hydroxyapatite along with geikielite (MgTiO3) and periclase (MgO) were the major phases. Based on the XRD analysis, the evaluation of structural features of the samples indicated that the average crystallite sizes of hydroxyapatite after 10 h of milling and subsequent thermal treatment at 700 °C were about 21 nm and 34 nm, respectively. Microscopic observations illustrated that the synthesized powders contained large agglomerates which consisted of significantly finer particles with spheroidal morphology. It is concluded that the mechanothermal method can be used to produce hydroxyapatite-based nanocomposite with appropriate structural and morphological features.
Highlights
The current development in bioceramic research is predominantly focused on calcium phosphate-based materials, as they show superior biological and mechanical properties over other materials [1 3]
It is clearly seen that the thermal treatment at 700 °C leads to the formation of MgTiO3 by the following reaction: MgO + TiO2 MgTiO3 ∆G298K = 25.410 kJ, ∆H298K = 26.209 kJ (6) It was reported that the decomposition temperature (600–800 °C) strongly depends on the preparation method of the HAp powders [12]
The calculated amounts of structural features indicated that increasing the annealing temperature might assist grain growth, so all the powders were comprised of nano-sized crystallites
Summary
The current development in bioceramic research is predominantly focused on calcium phosphate-based materials, as they show superior biological and mechanical properties over other materials [1 3]. Hydroxyapatite (HAp, Ca10(PO4)6(OH)2) has been significantly served in biomedical fields for its biocompatibility and osteoconductivity [4]. HAp is the most stable phase in physiological conditions, and its direct chemical boding to bone. Mechanothermal synthesis of hydroxyapatite-based nanocomposites was investigated. It should be noted that nanostructural calcium phosphate-based composite with appropriate stoichiometry, high purity and crystallinity could increase the densification and osseointegrative and bioactive properties [5]. The structural features (crystallite size, lattice strain and crystallinity) as well as morphological characteristics (particle size and shape, particle distribution and agglomeration) of the nanocomposites were investigated by using XRD, SEM/EDX and TEM techniques
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