Effect of YF3 on hot-pressed hydroxyapatite and monoclinic zirconia composites

Monoclinic zirconia and hydroxyapatite (HA) composites with or without 5 wt% YF3 were synthesized to investigate their mechanical properties and phase stability. HA decomposed to tri-calcium-phosphate and CaZrO3 in the 25 wt% ZrO2-75 wt% HA composite. However, thermal stability of the phases, densification, hardness and fracture toughness were improved when 5 wt% YF3 was added into the system. Five weight percent YF3 increased the transformation of monoclinic-ZrO2 into tetragonal/cubic-ZrO2 by incorporating the Y3+ ions present in YF3 when the hot pressing temperature was increased from 1100 to 1200 degrees C. Moreover, the stability of HA was also improved by incorporating the F- ions from YF3 in the place of OH- ions in HA. Substitution of OH- by F- ions was verified by the change in HA's hexagonal lattice parameters. A fracture toughness of 1.93 MPa root m was calculated for the same composite.


Effect of AlF3, CaF2 and MgF2 on hot-pressed hydroxyapatite-nanophase alpha-alumina composites
Evis, Zafer (2008-10-02)
Nanophase alpha-alumina and hydroxyapatite composites (with and without 5 wt% AlF3, CaF2 or MgF2 added separately) were hot pressed at 1100 degrees C and 1200 degrees C to investigate their mechanical properties and phase stability. Hydroxyapatite slightly decomposed to tri-calciurn-phosphate when there was no F- present. With the addition of AlF3, CaF2 or MgF2 into the composite, it improved its thermal stability and mechanical properties. Substitution of OH- by F- ions in hydroxyapatite was verified by th...
Effect of isomorphic atom substitution on the lattice parameters and the optical absorption edge of TIGaSe2-TllnSe2 mixed crystals
Hasanlı, Nızamı (2006-05-01)
The variation of lattice parameters of TlGaSe2-TlInSe 2 mixed crystals with composition have been investigated by using of X-ray diffraction technique. For the mixed crystals studied, a structural phase transition (monoclinic to tetragonal) due to atom substitution is observed when the sum of the tetrahedral covalent radii of the Ga(In) and the Se atoms in Ga(In)Se4 tetrahedra reaches a critical value of about 0.254 nm. From transmission and reflection measurements, the compositional dependence of the indir...
Effect of Conjugated Core Building Block Dibenzo[a,c]phenazine Unit on pi-Conjugated Electrochromic Polymers: Red-Shifted Absorption
Unver, Elif Kose; Tarkuc, Simge; Udum, Yasemin Arslan; Tanyeli, Cihangir; Toppare, Levent Kamil (2010-04-15)
A comparative investigation was undertaken for the electrosynthesis and electrochemical properties of three different electroactive polymers having a conjugated core building block, dibenzo[a,c]phenazine. A series of monomers has been synthesized as regards to thiophene based units; thiophene, 3-hexyl thiophene, and 3,4-ethylenedioxythiophene. The effects of different donor substituents on the polymers' electrochemical properties were examined by cyclic voltammetry. Introducing highly electron-donating (eth...
Effect of High-Density Nanoparticles on Recrystallization and Texture Evolution in Ferritic Alloys
Aydoğan Güngör, Eda; Carvajal-Nunez, Ursula; Vogel, Sven C.; Li, Meimei; Maloy, Stuart A. (MDPI AG, 2019-03-01)
Ferritic alloys are important for nuclear reactor applications due to their microstructural stability, corrosion resistance, and favorable mechanical properties. Nanostructured ferritic alloys having a high density of Y-Ti-O rich nano-oxides (NOs < 5 nm) are found to be extremely stable at high temperatures up to similar to 1100 degrees C. This study serves to understand the effect of a high density of nano-particles on texture evolution and recrystallization mechanisms in ferritic alloys of 14YWT (14Cr-3W-...
Effects of Fe-TiB2 addition as binder phase on the liquid phase sintering behaviour of tungsten carbide cermets
Tankut, A; Timucin, M (2004-01-01)
The sintering behaviour of tungsten carbide compacts with a eutectic Fe-TiB2 mixture was studied. In order to have a clear view of the mechanisms that occur during liquid phase sintering, the hardness, transverse rupture strength, toughness, and densification values were measured and the micrographs were examined for WC-Fe-TiB2 cermets with varying compositions, sintering times and sintering temperatures. The findings were then with the propeerties known for WC-Fe and WC-Co cermets.
Citation Formats
Z. Evis, “Effect of YF3 on hot-pressed hydroxyapatite and monoclinic zirconia composites,” MATERIALS CHEMISTRY AND PHYSICS, pp. 76–79, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47016.