title: Influence of phase separation on the devitrification of 45S5 bioglass.
abstract: The devitrification of the 45S5 variety of bioactive glasses (BGs) in relation to phase separation is studied with scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and positron annihilation lifetime spectroscopy techniques. It is shown that the type of phase separation (such as spinodal vs. droplet-like) has a pronounced effect on the activation energy of viscous flow and crystallization, the onset temperature of crystallization and the void size distribution at the nanoscale. Generally, the Johnson-Mehl-Avrami (JMA) relation does not describe crystallization kinetics in bulk 45S5 BG. However, for powder samples (<300 μm) the difference in crystallization kinetics, which is surface-driven for the two kinds of glasses, becomes much smaller, and can be described with the JMA relation under some circumstances.
authors: Department of Physics and Astronomy, Austin Peay State University, 601 College St, Clarksville, TN 37044, USA; Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195, USA.
authors: R
authors: R
authors: Golovchak
authors: Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195, USA.
authors: P
authors: P
authors: Thapar
authors: Department of Physics of Opole University of Technology, 75, Ozimska str., Opole, PL-45370, Poland.
authors: A
authors: A
authors: Ingram
authors: Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195, USA.
authors: D
authors: D
authors: Savytskii
authors: Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195, USA. Electronic address: h.jain@lehigh.edu.
authors: H
authors: H
authors: Jain
mesh_terms: D002152:Calorimetry, Differential Scanning; D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization; D005898:Glass / Q000737:chemistry*; D044367:Phase Transition; D056951:Photoelectron Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: C425330:bioactive glass 45S5
keywords: Bioactive glass; Bioscaffold; Crystallization; Nanostructure; Phase separation