Properties of iron-containing nanohydroxyapatite-based composites

The paramagnetic properties of compounds resulting from the synthesis of nanohydroxyapatite in the presence of Fe(III) ions have been studied by electron paramagnetic resonance, Mössbauer spectroscopy, and magnetochemistry. Based on the obtained results on the mechanism of the reaction between an orthophosphoric acid solution and an aqueous calcium hydroxide suspension, we have found conditions for incorporating Fe(III) impurity ions into hydroxyapatite. We have studied samples differing in the sequence in which reagents were mixed and in hydroxyapatite crystallite formation conditions. It has been shown that, in all instances, the composition and properties of the iron-containing phases in the composites depend significantly on both synthesis and heat treatment conditions.