Fourier transform infrared spectra of technologically modified calcium phosphates

Abstract

Calcium phosphate powders were synthesized by wet-chemical precipitation method using CaCO3 and H3PO4 as starting materials. Influence of technological parameters on chemical composition of as-prepared and thermal treated calcium phosphate samples were investigated. The following technological parameters were varied: temperature of the suspension during the process of synthesis (T, °C), ending pH value, aging time of suspension (τ, h) and thermal processing (T, °C; τ, h). The obtained calcium phosphates powders were identified and characterized using Fourier transform infrared spectroscopy method and X-ray diffraction. FTIR spectra of as-synthesized calcium phosphate powders showed characteristic chemical bands of hydroxyapatite (PO43-, OH-, H2O absorbed, CO32-, HPO42-) at definite wave number ranges. Carbonate and OH- absorbed bands disappear after calcination above 900°C. The experimental results of FTIR spectra X-ray diffraction showed biphasic mixtures containing HAp and β-tricalciumphosphate (β-TCP). The secondary phase (β-TCP) was formed after calcination HAp samples at 1000°C and above. © 2008 Springer-Verlag.