KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Bongkarn, TheerachaiSubject: search.filters.subject.dielectric constant

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Optimum conditions for fabrication high-density KNN-LS-BF ceramics by combustion method
    (2013-12-01)
    Panya, Peerapong
    ;
    Wattanawikkam, Chakkaphan
    ;
    Laowanidwatana, Artid
    ;
    Vittayakorn, Naratip
    ;
    Bongkarn, Theerachai
    The 0.996(0.95K<inf>0.5</inf>Na<inf>0.5</inf>NbO<inf>3</inf>-0.05LiSbO <inf>3</inf>)-0.004BiFeO<inf>3</inf> (KNN-LS-BF) ceramics were prepared by the combustion method using glycine as a fuel. The raw materials were mixed and calcined at various calcination temperatures (650-750°C) with different dwell time (0.5-3 h). Then, the calcined powders were pressed and sintered at various temperatures (1000-1100°C) with 0.5-4 h dwell time. The highest % perovskite orthorhombic phase was found in powder calcined at 700°C for 1 h. For the sintered pellets, the orthorhombic structure was found in ceramic sintered at 1075°C for 2 h using heating and cooling rate of 10°C/min. The SEM photographs showed square or rectangular morphology. The average grain size increased with the increasing of soak time. The highest densisty (4.47 g/cm<sup>3</sup>), maximum dielectric constant (ε<inf>r</inf> = 6180) and lowest dielectric loss (tanδ = 0.1) at T<inf>c</inf> were obtained in the sample sintered at 1075°C for 3 h. The densest sample showed the P <inf>r</inf> = 14.3 μC/cm<sup>3</sup> and E<inf>c</inf> = 20.68 kV/cm at 40 kV/cm. © 2013 Copyright Taylor and Francis Group, LLC.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Influence of sintering temperature on phase formation, microstructure and dielectric properties of calcium and strontium Doped BNT ceramics prepared via combustion technique
    (2013-01-01)
    Sittiketkorn, Panadda
    ;
    Laowanidwatana, Artid
    ;
    Vittayakorn, Naratip
    ;
    Bongkarn, Theerachai
    Influence of sintering temperature on phase formation, microstructure and dielectric properties of calcium and strontium doped BNT ceramics (BNTST20 and BNTCT2) were investigated. The BNTST20 and BNTCT2 ceramics were prepared using the combustion technique. The structural phase of the BNTST20 ceramics indexed in a cubic phase, while the BNTCT2 ceramics indexed in a rhombohedral phase. The average grain size tended to increase with increasing sintering temperature. The density and the dielectric constant at Curie temperatures increased with increasing sintering temperature up to 1200°C and 1150°C, thereafter they decreased for BNTST20 and BNTCT2 ceramics, respectively. Moreover, the highest density (5.59 and 5.57 g/cm<sup>3</sup>) ceramics exhibited the highest dielectric constant at Curie temperatures (∼4733 and ∼3218) for BNTST20 and BNTCT2, respectively. The ferroelectric properties were also investigated. © 2013 Copyright Taylor and Francis Group, LLC.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    The structural phase and microstructures of perovskite Ba(Ti 1-xZr x)O 3 ceramics using the combustion route
    (2009-12-01)
    Phungjitt, Nalinee
    ;
    Panya, Perapong
    ;
    Bongkarn, Theerachai
    ;
    Vittayakorn, Naratip
    Ba(Ti <inf>1-x</inf>Zr <inf>x</inf>)O <inf>3</inf>; BTZ (x = 0.20 and 0.25) ceramics are attractive candidates for dynamic random access memories, tunable microwave devices and capacitors. In this study, the preparation of BTZ powders and ceramics fabricated by the combustion method were studied in detail. The calcination and sintering conditions were performed from 600 to 900°C for 4 h and from 1300 to 1450°C for 2 h, respectively. The highest percentage of the cubic perovskite phase was found in the powders that were calcined at 800°C. A pure cubic perovskite structure was found in all ceramic samples. The average grain size increased with increasing sintering temperatures. Dielectric constant-temperature plots showed a maximum peak value of 7500 and 8300 for x = 0.20 and 0.25. The phase transition temperature of the BTZ ceramics occurred at 30°C and 10°C for x = 20 and 25, respectively. © 2009 World Scientific Publishing Company.