Physico-chemical and thermochemical studies of the hydrolytic conversion of amorphous tricalcium phosphate into apatite
- IPEIT, 2 rue Jawar El Nehri, Monfleury, 1089 Tunis, Tunisie (Tunisia)
- CIRIMAT, Ecole Nationale Swuperieure des Ingenieurs en Arts Chimiques et Technologiques, INPT-ENSIACET, UMR CNRS 5085, 118 route de Narbonne, 31077 Toulouse cedex 4 (France)
- Laboratoire de Thermodynamique Appliquee, Departement de Chimie, Faculte des Sciences, Campus Universitaire, Tunis 1060, Tunisie (Tunisia)
The conversion of amorphous tricalcium phosphate with different hydration ratio into apatite in water at 25 deg. C has been studied by microcalorimetry and several physical-chemical methods. The hydrolytic transformation was dominated by two strong exothermic events. A fast, relatively weak, wetting process and a very slow but strong heat release assigned to a slow internal rehydration and the crystallization of the amorphous phase into an apatite. The exothermic phenomenon related to the rehydration exceeded the crystalline transformation enthalpy. Rehydration occurred before the conversion of the amorphous phase into apatite and determined the advancement of the hydrolytic reaction. The apatitic phases formed evolved slightly with time after their formation. The crystallinity increased whereas the amount of HPO{sub 4}{sup 2-} ion decreased. These data allow a better understanding of the behavior of biomaterials involving amorphous phases such as hydroxyapatite plasma-sprayed coatings.
- OSTI ID:
- 20725907
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 178; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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