Processing of a natural hydroxyapatite powder: From powder optimization to porous bodies development

This paper deals with the development of macro-porous components made of a carbonated hydroxyapatite (HAp) nanopowder which was extracted from pig bones. Prior to sintering, the powder was treated at 700 °C for 1 h. During calcination, a partial carbonate decomposition occurred yielding CaO. In order to eliminate this by-product, the calcined HAp was washed in distilled water several times, checking the effect of washings by FT-IR spectroscopy. Then, the thermal stability of the as-calcined and washed powders treated in the range 800–1400 °C was investigated by XRD. After that, macro-porous materials made of washed HAp powder were prepared through a modified gelcasting process, using agar as a natural gelling agent and polyethylene spheres as the pore formers.