title: Ultrastructural observation of single-crystal apatite fibres.
abstract: Hydroxyapatite (HAp) has been widely used as a biomaterial for substituting human hard tissues such as bone. By altering the morphology of HAp crystals, novel properties may be produced by controlling the orientation of the crystal planes. Apatite fibres were successfully synthesized by precipitation from aqueous solutions containing Ca(NO(3))(2), (NH(4))(2)HPO(4), urea and HNO(3). The products were composed of carbonate-containing apatite fibres with preferred orientation along the {h00} planes. Examination of individual fibres using transmission electron microscopy showed that the as-synthesized apatite fibres were highly strained single crystals with the c-axis orientation parallel to the long axis of the fibre. The crushed fibres consisted of domains that were preferentially oriented with the c-axis parallel to the long axis of the fibres. When the apatite fibres were heated to 800, 1000 and 1200 degrees C for 1h, the domains were removed and grain boundaries, dislocations and voids were formed.
authors.affiliation: Department of Industrial Chemistry, School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, 214-8571, Japan. mamorua@isc.meiji.ac.jp
authors.forename: Mamoru
authors.initials: M
authors.lastname: Aizawa
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Porter
authors.forename: Serena M
authors.initials: SM
authors.lastname: Best
authors.forename: William
authors.initials: W
authors.lastname: Bonfield
mesh_terms: D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D003461:Crystallography / Q000379:methods*; D017886:Durapatite / Q000032:analysis / Q000737:chemistry*; D006358:Hot Temperature; D008422:Materials Testing; D043942:Nanotubes / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite