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Structural and proton transport studies on nanocrystalline [Ca 10 (PO 4 ) 6 (OH) 2 ] (HAp), HAp–Nafion® composite, and natural human bone
Author(s) -
Jena H.,
Rao Ch. Venkateswara,
Eddy Fannie Posey,
Dooley Jonathan,
Rambabu B.
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200824429
Subject(s) - nanocrystalline material , materials science , selected area diffraction , nafion , scanning electron microscope , transmission electron microscopy , analytical chemistry (journal) , fourier transform infrared spectroscopy , chemical engineering , nuclear chemistry , crystallography , chemistry , nanotechnology , electrochemistry , organic chemistry , composite material , electrode , engineering
Nanocrystalline hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 (HAp) is synthesized from hydroxide gels at room temperature using sonochemical technique. The as‐synthesized material is characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Fourier transform infrared (FT‐IR), and solid‐ state ( 1 H and 31 P) NMR techniques. Hexagonal structure with space group P6 3 / m is evident from powder XRD. Microscopic analysis with SAED indicates the nanocrystalline nature of the compound. Average particle size of 30 nm with excellent phase purity in good stoichiometric ratios of HAp is observed. The prevalence of protons as hydroxyls in apatitic structure of HAp is evident from FT‐IR and solid‐state NMR. The microstructure and proton conducting properties of the synthesized material are compared with the natural human bone powder having similar constituents. The sonochemically prepared HAp, and HAp‐Nafion® composite exhibited excellent AC conductivities ∼10 −5 S cm −1 at 650 °C and ∼10 −5 S cm −1 at 160 °C, respectively, may find application as an electrolyte for low temperature solid oxide fuel cells (LT‐SOFCs) and high temperature polymer electrolyte fuel cells (HT‐PEFCs) applications.