title: Preparation of magnesium-substituted hydroxyapatite powders by the mechanochemical-hydrothermal method.
abstract: Magnesium-substituted hydroxyapatite (Mg-HAp) powders with different crystallinity levels were prepared at room temperature via a heterogeneous reaction between Mg(OH)(2)/Ca(OH)(2) powders and an (NH(4))(2)HPO(4) solution using the mechanochemical-hydrothermal route. The as-prepared products contained unreacted Mg(OH)(2) and therefore had to undergo purification in ammonium citrate aqueous solutions at room temperature. X-ray diffraction, infrared spectroscopy, thermogravimetric and chemical analyses were performed and it was determined that the purified powders were phase-pure Mg-HAp containing 0.24-28.4 wt% of Mg. The concentration of Mg was slightly lower near the surface than in the bulk of the HAp crystals as indicated by X-ray photoelectron spectroscopy. Dynamic light scattering revealed that the median particle size of the room temperature Mg-HAp powders was in the range of 102 nm-1.2 microm with a specific surface area between 91 and 269 m(2)/g. Scanning electron microscopy confirmed that the Mg-HAp powders consisted of submicron agglomerates of nanosized crystals, less than approximately 20 nm.
authors.affiliation: Department of Ceramic and Materials Engineering, Rutgers University, 607 Taylor Rd, Piscataway, NJ 08854-8087, USA. w_suchanek@yahoo.com
authors.forename: Wojciech L
authors.initials: WL
authors.lastname: Suchanek
authors.forename: Kullaiah
authors.initials: K
authors.lastname: Byrappa
authors.forename: Pavel
authors.initials: P
authors.lastname: Shuk
authors.forename: Richard E
authors.initials: RE
authors.lastname: Riman
authors.forename: Victor F
authors.initials: VF
authors.lastname: Janas
authors.forename: Kevor S
authors.initials: KS
authors.lastname: TenHuisen
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry / Q000302:isolation & purification; D011232:Chemical Precipitation; D003460:Crystallization / Q000379:methods*; D017886:Durapatite / Q000737:chemistry*; D006358:Hot Temperature; D008274:Magnesium / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011208:Powders; D013314:Stress, Mechanical; D014867:Water / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011208:Powders; D014867:Water; D017886:Durapatite; D008274:Magnesium