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Advanced Ceramics Progress - Volume:1 Issue: 2, 2015 summer

Advanced Ceramics Progress
Volume:1 Issue: 2, 2015 summer

  • تاریخ انتشار: 1394/07/11
  • تعداد عناوین: 8
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  • A. Faeghinia Pages 1-5
    In this work, the structural properties and spectroscopic behavior 80 mol.%TeO2-20mol.%LiF glasses which were doped with 0. 05, 0. 2 mole% Gd2O3 have been studied. It was shown that, by increasing the amount of Gd2O3 the glass stability was decreased. The PL emissions at 431nm and 627nm wavelengths were distinguished by 320nm excitation. The FT-IR analysis showed deformed TeO4 groups in these glasses.
    Keywords: Tellurite glass, FT, IR, UV visible, Luminescence
  • Z. Abadi, P. Sangpour, F. Tajabadi Pages 6-10
    Graphene oxide (GO) thin films were simply deposited on fluorine doped tin oxide (FTO) substrate via a low-voltage electrodeposition. The GO and GO thin films were characterized by Zeta Potential، X-ray diffraction، Ultraviolet-Visible spectroscopy، atomic force microscopy، Fourier transform infrared spectroscopy، field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. The results confirm existence of multi-layered graphene oxide. UV-vis spectra exhibit GO thin films possess 60-80% transmittance in the visible region. Calculating calculating optical band gap from UV-vis spectra either for GO solution and GO thin film suggests a simultaneous reduction occurred during deposition.
    Keywords: Graphene oxide, Graphene Oxide thin film, electrodeposition, GO optical band gap
  • S. Abdolazizi, R. Naghizadeh, S. Baghshahi Pages 11-17
    Alumina-Mullite-Zirconia ceramic composites were prepared by reaction sintering of alumina, zircon mixture and the sintering aids of magnesia and titania at temperatures of 1400 and 1600 C for 2 hours. The development of different phases and microstructures of the composites were analysed to assess the relative influence of the additives on the formation of alumina-zirconia-mullite composite. Bulk density, phase combination, and microstructure of the sintered samples were examined by Archimedes method, X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results of the study revealed the successful formation of the alumina-mullite-zirconia composite by the reaction sintering method at temperature of 1600C. By the same token, the sample containing 6 wt.% of sintering aid shows improvement in density.
    Keywords: Alumina, Zirconia, Mullite, Composite, MgO, TiO2
  • F. Asjadi, E. Salahi, I. Mobasherpour Pages 18-23
    Titanium and fluoride-containing hydroxyl apatite were synthesized through precipitation method following by a hydrothermal stage at 100oC for 6 hours. XRD analysis of the sample scalcinedat650oC for 1 hour revealed that all samples have pure apatite structure. The existence of Fluoride substitution in apatite structure was confirmed by FTIR(Fourier Transform Infrared Spectroscopy) analysis. Surfaces of the samples were studied by zeta potential measurements. Investigating cell parameter and also FWHM (Full Width at Half Maximum) of phosphate v1 peak in Raman spectra showed some different behaviour in samples with titanium and high fluoride concentration attributed to different position of titanium in these samples. Scanning electron microscopy (SEM) was used for investigating the morphology of samples. The Morphology of particles was not affected by adding titanium and fluoride.
    Keywords: Ti containing hydroxyapatite, fluorohydroxyapatite, surface charges, nano structures
  • A. Massoudi, M. E. Azim, Araghi, M. Keihan Asl Pages 24-28
    Nano-porous silicon were simply prepared from p-type single crystalline silicon wafer by electrochemical etching technique via exerting constant current density in two different HF-Ethanol and HF-Ethanol-H2O solutions. The mesoporous silicon layers were characterized by field emission scanning electron microscopy and scanning electron microscopy. The results demonstrate that the width of nano-pores changes from 7 nm to 60 nm by varying current density from 10 mA/Cm 2 to 40 mA/Cm 2, respectively and the depth of nano-pores also alters by applying different values of etching duration. It is concluded that varying current density leads to different width of pores while varying etching duration results in various depth of pores. Such etch tuning process is applicable for fabricating different nano-sized porous silicon for many modern electronic devices.
    Keywords: Nano, porous Silicon, mesopore, Electrochemical Etch Tuning, HF, Ethanol, HF, Ethanol, H2O
  • A. Amirimehr, E. Ghasemi, A. Fazlali Pages 29-33
    In this work، a stable NiFe2O4 paraffin based ferrofluid was prepared via high energy milling. The rheological properties of ferrofluid were studied. Bingham plastic، HerschelBulkley and Casson models were used to evaluate the shear stress-shear rate dependency. The ferrofluid exhibited a shear thinning behaviour for all studied magnetic field. The magneto-viscous effect and thixotropy of ferrofluid were studied and the role of formation and destruction of magnetically induced structures and the interactions of nanoparticles and aggregates were discussed.
    Keywords: Nickel ferrite, Magnetic nanoparticle, Ferrofluid, Rheological property, Magnetoviscous effect, thixotropy
  • Wear Behavior in Micro and Nano-Structured WC-9Co-0.7VC Cemented Carbide Produced by Rapid Hot Press Sintering
    H. Sedaghati, M. Tamizifar Pages 34-39
    The effect of CaO on the formation of β- and γ-zirconia nanoparticles from α-zirconia was investigated and their stability evaluated via mechanical activation. α-ZrO2+8. 5wt%CaO powder was milled for 2-150 hours with ball-to-powder weight ratios (BPWR) of 40:1 and 60:1. Structural evaluations were conducted using X-Ray diffraction and scanning electron microscope (SEM). Thermal analysis was carried out using Differential Scanning Calorimetry (DSC). Results showed that، γ-zirconia (with a cubic structure) was obtained by ball milling of α-ZrO2+8. 5wt%CaO at room temperature. It was found that α to γ phase transformation began after two hours of milling and completed after 48 hours with a BPWR of 40:1. Moreover، the Williamson-Hall equation indicated that the particle size of α-ZrO2+8. 5wt%CaO was reduced to 50 nanometers and reached its equilibrium point after 24 hours of milling and was unchanged after that. In addition، DSC analysis showed that β-zirconia and γ-zirconia were unstable in pure ZrO2 powder، while CaO addition led to the stabilization of ZrO2 as β-zirconia and γ-zirconia after ball milling.
    Keywords: WC–Co, Cemented carbide, Nano, structured hard, metal, Hot pressing, Wear
  • M. Golzar Shahri, A. Shafyei, A. Saidi, K. Abtahi Pages 40-44
    The effect of CaO on the formation of β- and γ-zirconia nanoparticles from α-zirconia was investigated and their stability evaluated via mechanical activation. α-ZrO2+8. 5wt%CaO powder was milled for 2-150 hours with ball-to-powder weight ratios (BPWR) of 40:1 and 60:1. Structural evaluations were conducted using X-Ray diffraction and scanning electron microscope (SEM). Thermal analysis was carried out using Differential Scanning Calorimetry (DSC). Results showed that، γ-zirconia (with a cubic structure) was obtained by ball milling of α-ZrO2+8. 5wt%CaO at room temperature. It was found that α to γ phase transformation began after two hours of milling and completed after 48 hours with a BPWR of 40:1. Moreover، the Williamson-Hall equation indicated that the particle size of α-ZrO2+8. 5wt%CaO was reduced to 50 nanometers and reached its equilibrium point after 24 hours of milling and was unchanged after that. In addition، DSC analysis showed that β-zirconia and γ-zirconia were unstable in pure ZrO2 powder، while CaO addition led to the stabilization of ZrO2 as β-zirconia and γ-zirconia after ball milling.
    Keywords: Ball milling, Zirconia nanoparticles, Phase transformation phase stability, DSC analysis