title: A comparative physico-chemical study of chlorapatite and hydroxyapatite: from powders to plasma sprayed thin coatings.
abstract: Due to their bioactivity and osteoconductivity, hydroxyapatite (HA) plasma sprayed coatings have been widely developed for orthopedic uses. However, the thermodynamic instability of HA leads frequently to a mixture of phases which limit the functional durability of the coating. This study investigates the plasma spraying of chlorapatite (ClA) powder, known to melt without decomposition, onto pure titanium substrates using a low energy plasma spray system (LEPS). Pure ClA powder was prepared by a solid gas reaction at 950 °C and thermogravimetric analysis showed the good thermal stability of ClA powder in the range 30-1400 °C compared to that of the HA powder. Characterization of ClA coating showed that ClA had a very high crystalline ratio and no other crystalline phase was detected in the coating. HA and ClA coatings composition, microstructure and in vitro bioactivity potential were studied, compared and discussed. In vitro SBF test on HA and ClA coatings revealed the formation of a poorly crystalline apatite on the coating surface suggesting that we could expect a good osteoconductivity especially for the ClA coating prepared by the LEPS system.
authors.affiliation: Université de Toulouse, CIRIMAT CNRS-INPT-UPS, ENSIACET, Toulouse, France. imane.demnati@ensiacet.fr
authors.forename: I
authors.initials: I
authors.lastname: Demnati
authors.forename: D
authors.initials: D
authors.lastname: Grossin
authors.forename: C
authors.initials: C
authors.lastname: Combes
authors.forename: M
authors.initials: M
authors.lastname: Parco
authors.forename: I
authors.initials: I
authors.lastname: Braceras
authors.forename: C
authors.initials: C
authors.lastname: Rey
mesh_terms: D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry; D055598:Chemical Phenomena; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003460:Crystallization; D004355:Drug Stability; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D033362:Powder Diffraction; D011208:Powders; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D011208:Powders; C051449:chlorapatite; D017886:Durapatite