Improvement in sinterability and phase stability of hydroxyapatite and partially stabilized zirconia composites

Evis, Zafer
Composites of hydroxyapatite with partially stabilized zirconia with MgO or MgF2 were pressureless sintered between 1000 degrees C and 1300 degrees C. The reactions and transformations of phases were verified by X-ray diffraction. For the hydroxyapatite and zirconia composites with MgO, calcium from the hydroxyapatite diffused into the zirconia phase, and the hydroxyapatite decomposed to tri-calcium phosphate at sintering temperatures higher than 1000 degrees C. Above about 1200 degrees C, CaZrO3 was formed. Composites containing the MgF2 decomposed slower than the composites with MgO, which was verified by the changes in the lattice volume of the hydroxyapatite left in these composites. Fluorine ions in MgF2 diffused into hydroxyapatite, which resulted in thermal stability at high sintering temperatures. Composites with MgF2 had higher hardness than those with MgO. The lowest porosity was found in a composite initially containing 10 wt% partially stabilized zirconia and 5 wt% MgF2. (C) 2008 Elsevier Ltd. All fights reserved.


Activity-corn position relations in MuCr(2)O(4)-CoCr2O4 solid solutions and stabilities of MnCr2O4 and CoCr2O4 at 1300 degrees C
Koc, N; Timucin, M (Wiley, 2005-09-01)
Phase equilibria in the system MnO-CoO-Cr2O3 were investigated at 1300 degrees C under controlled oxygen partial pressures by using the gas equilibration technique. The CoO activities in various phase assemblages of the system were measured by determining the partial pressures of oxygen in the gas phase for coexistence with metallic cobalt. The activity data revealed that at 1300 degrees C, MnO-CoO and MnCr2O4-CoCr2O4 solid solutions exhibit mild positive departures from ideal behavior. The activities in th...
Highly Efficient Room Temperature Synthesis of Silver-Doped Zinc Oxide (ZnO:Ag) Nanoparticles: Structural, Optical, and Photocatalytic Properties
Yildirim, Ozlem Altintas; Ünalan, Hüsnü Emrah; Durucan, Caner (Wiley, 2013-03-01)
Synthesis of silver-doped zinc oxide (ZnO:Ag) nanoparticles through precipitation method has been reported. The synthesis was conducted at room temperature and no subsequent thermal treatment was applied. ZnO nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), fourier transmission infrared spectroscopy (FTIR), and ultraviolet-visible (UVVis) spectroscopy. Detailed crystallographic investigation was accomplished through ...
Thermal degradation of poly(allyl methacrylate) by mass spectroscopy and TGA
Vardareli, Tugba Kantav; Keskin, Selda; Usanmaz, Ali (Informa UK Limited, 2006-10-01)
Allyl methacrylate, AMA was polymerized in CCl4 solution by alpha,alpha'-azoisobutyronitrile at 50 degrees C. The thermal degradation mechanism of PAMA was characterized by MS, TGA-FT-IR and FT-IR-ATR methods. The mass spectrum and TGA thermogram showed two stage degradation. The first stage of degradation was mostly linkage type degradation for the fragmentation of pendant allyl groups at 225 - 350 degrees C. In the second stage, at 395 - 515 degrees C, the degradation is random scission and depolymerizati...
TAS, AC; AKINC, M (Wiley, 1994-11-01)
The high-temperature phase relations in the system Ce2O3-Ce2Si2O7 have been studied in the temperature range 1150 degrees-1970 degrees C in inert and reducing atmospheres by conventional quenching and differential thermal analysis. Three eutectic reactions were found to occur at 1664 degrees C and 27 mol% SiO2 between Ce2O3 and Ce2SiO5, at 1870 degrees C and 54 mol% SiO2 between Ce2SiO5 and Ce-4.67(SiO4)(3)O, and at 1762 degrees C and 65 mol% SiO2 between Ce-4.67(SiO4)(3)O and Ce2Si2O7. Microstructural char...
Material and Elastic Properties of Al-Tobermorite in Ancient Roman Seawater Concrete
Jackson, Marie D; Moon, Juhyuk; Gotti, Emanuele; Taylor, Rae; Chae, Sejung R; Kunz, Martin; Emwas, Abdul-Hamid; Akgül, Çağla; Guttmann, Peter; Levitz, Pierre; Wenk, Hans-Rudolf; Monteiro, Paulo J (Wiley, 2013-08-01)
The material characteristics and elastic properties of aluminum-substituted 11 angstrom tobermorite in the relict lime clasts of 2000-year-old Roman seawater harbor concrete are described with TG-DSC and Si-29 MAS NMR studies, along with nanoscale tomography, X-ray microdiffraction, and high-pressure X-ray diffraction synchrotron radiation applications. The crystals have aluminum substitution for silicon in tetrahedral bridging and branching sites and 11.49(3)angstrom interlayer (002) spacing. With prolonge...
Citation Formats
Z. Evis and I. KUTBAY, “Improvement in sinterability and phase stability of hydroxyapatite and partially stabilized zirconia composites,” JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, pp. 621–628, 2009, Accessed: 00, 2020. [Online]. Available: