Yazar "Ovecoglu, Mustafa Lutfi" seçeneğine göre listele

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  • Küçük Resim
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    Mechanochemical synthesis and consolidation of nanostructured cerium hexaboride
    (Univ Novi Sad, Fac Technology, 2019) Agaogullari, Duygu; Balci, Ozge; Akçamlı, Nazlı; Suryanarayana, Challapalli; Duman, Ismail; Ovecoglu, Mustafa Lutfi
    This study reports on the mechanochemical synthesis (MCS) and consolidation of nanostructured CeB6 powders of high purity. CeB6 powders were prepared via MCS by milling CeO2, B2O3 and Mg powders in a high-energy ball mill for different milling times. The effects of milling time on the formation, microstructure and thermal behaviour of the synthesized powders were investigated and the optimum MCS duration was determined. Purified powders were obtained after HCl leaching by removing MgO by-product. The prepared powders were characterized by a number of techniques including X-ray diffraction, stereomicroscopy, scanning and transmission electron microscopy coupled with energy dispersive spectrometry, differential scanning calorimetry, atomic absorption spectrometry, particle size analysis, surface area analysis and vibrating sample magnetometry. The high-purity CeB6 powders having an average particle size of 86 nm were consolidated by cold-pressing followed by pressureless sintering at 1700 degrees C for 5 h. The bulk CeB6 specimen was investigated for its microstructure, density, electrical resistivity, surface roughness and some mechanical properties (microhardness and wear behaviour). The relative density, electrical resistivity, microhardness and wear rate of the bulk CeB6 were determined as 95.2% TD, 57.50 mu W.cm, 11.65 GPa and 1.46 x 10(-4) mm(3)/N.m, respectively.
  • Küçük Resim Yok
    Öğe
    Thermomechanical properties of aluminium titanate (Al2TiO5)-reinforced forsterite (Mg2SiO4) ceramic composites
    (Elsevier Sci Ltd, 2018) Küçük, İsrafil; Boyraz, Tahsin; Gokce, Hasan; Ovecoglu, Mustafa Lutfi
    Aluminium titanate (Al2TiO5)-reinforced forsterite (Mg2SiO4) ceramics were prepared by the powder metallurgy route including sintering the Al2TiO5-reinforced Mg2SiO4 green compacts at 1600 degrees C. Sivas talc (3MgO center dot 4SiO(2)center dot H2O) was used as a precursor for the Mg2SiO4 ceramics due to its excellent mechanical properties like thermal shock and abrasion resistance. In order to investigate thermal shock resistance behaviour, the as prepared samples were quenched in water and assessed. Investigations were carried out to study the effect of Al2TiO5 addition on microstructural, physical, thermal and mechanical properties of Al2TO5-reinforced Mg2SiO4 ceramic composites. The thermal and mechanical properties were examined before and after thermal shock tests. The results showed that the best thermal expansion coefficient (0.76 x 10(-6) (K-1)) and thermal shock resistance (6.82 GPa) of the Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites were obtained after thermal shock test, which were better than those of the other concentrations of the Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites. These findings suggest that 20 wt% Al2TiO5-reinforced forsterite (Mg2SiO4) ceramic composites possess good thermomechanical properties and thus might be suitable for potential applications such as filter material, pharmaceuticals, cosmetic manufacturing, optical, and chemical devices.