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Author: search.filters.author.Pulphol, Nattakarn

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    Fine Grain BaTiO3-Co0.5Ni0.5Fe2O4 Ceramics Prepared by the Two-Stage Sintering Technique
    (2015-10-30)
    Pulphol, Nattakarn
    ;
    Muanghlua, Rangson
    ;
    Niemcharoen, Surasak
    ;
    Vittayakorn, Naratip
    ;
    Vittayakorn, Wanwilai
    This work investigated the improvement of density and controllable grain size of multiferroic ceramics by using the system of (0.8)BaTiO<inf>3</inf>-(0.2)Co<inf>0.5</inf>Ni<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> nanocomposites via the two-stage sintering technique. The sintering process was divided into two steps. Firstly, samples were fired at the optimized temperature of T<inf>1</inf> to activate grain boundary migration in order to obtain an initial high density. Secondly, the samples were cooled immediately to the temperature of T<inf>2</inf> and soaked at various times to enable dense ceramics without grain growth. All of the samples were characterized by an X-ray diffractometer, and the results confirmed that all samples were composite ceramics. Scanning electron microscopy showed the grain size of all the samples and proved that the two-stage sintering technique achieved fine grain ceramics when compared with traditional sintering. Electrical properties of all the samples were investigated using an LCR meter at room temperature to 200°C with various frequencies, and magnetic properties were characterized by a vibrating sample magnetometer.
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    Fabrication and properties of BaTiO3-CoFe2O 4 nanocomposites
    (2013-12-01)
    Vittayakorn, Wanwilai C.
    ;
    Pulphol, Nattakarn
    ;
    Muanghlua, Rangson
    ;
    Vittayakorn, Naratip
    In this work, BaTiO<inf>3</inf>-xCoFe<inf>2</inf>O<inf>4</inf>, where x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5, nanocomposites were prepared by conventional mixing method and followed by normal sintering in air. The effect of processing condition on phase formation, microstructure, magnetic and electrical properties of the BaTiO<inf>3</inf>-CoFe<inf>2</inf>O<inf>4</inf> nanocomposites was investigated. The phase development and microstructural evolution of this system have been determined via X-ray diffractometer and scanning electron microscope. From the results, it concludes that phase formation, microstructure, electrical and magnetic properties of the BaTiO<inf>3</inf>-xCoFe<inf>2</inf>O<inf>4</inf> nanocomposites strongly depend on chemical composition. © 2013 Copyright Taylor and Francis Group, LLC.
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    Magnetoelectric properties of BaTiO3 - Co0.5Ni0.5Fe2o4 composites prepared by the conventional mixed oxide method
    (2013-10-29)
    Pulphol, Nattakarn
    ;
    Muanglua, Rangson
    ;
    Niemcharoen, Surasak
    ;
    Pecharapa, Wisanu
    ;
    Vittayakorn, Wanwilai C.
    Multiferroics, which display simultaneous ferrimagnetic and ferroelectric properties, have been interesting recently because of their potentially significant applications in multifunctional devices such as magnetic resonance, drug delivery, high-density data storage, ferrofluid technology, etc. Composites combining BaTiO<inf>3</inf> with Co<inf>0.5</inf>Ni<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> have influenced the interest of many researchers, due to their outstanding and distinguished character called magnetoelectric (ME). In this work, ferrimagnetic-ferroelectric composites of BaTiO<inf>3</inf> nanopowder and Co<inf>0.5</inf>Ni<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> nanopowders were prepared by a conventional mixed oxide method. The multiferroic ceramics were compounded with the formula, (1-x)BaTiO<inf>3-</inf>(x) Co<inf>0.5</inf>Ni<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf>, in which x = 0, 0.05, 0.10, 0.20 and 0.35. All of the compositions were analyzed by an X-ray diffractometer (XRD) in order to reveal the phase of perovskite and spinal structure. Scanning electron microscopy (SEM) was used to examine the variation of morphology and grain size of the composited ceramics. The magnetism of all the ceramics was measured using a vibrating sample magnetometer (VSM). The results showed that microstructure and the amount of ferrite are related strongly with magnetization. © (2013) Trans Tech Publications, Switzerland.
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    The influence of BMN addition on the phase formation, microstructure and dielectric property of BaTiO3 ceramic
    (2013-01-01)
    Vittayakorn, Wanwilai C.
    ;
    Pulphol, Nattakarn
    ;
    Roongtao, Rachanusorn
    ;
    Muanghlua, Rangson
    ;
    Vittayakorn, Naratip
    Solid solutions of the (1-x)BT-xBMN system were prepared successfully by the solid state reaction method followed by normal sintering in air. The phase formation, microstructure and dielectric property of BT-BMN ceramics were investigated as a function of compositions. XRD results showed a single perovskite phase for all compositions. Cubic-tetragonal transformation was found after adding BMN into the system. SEM micrographs revealed two very different grain sizes in the ceramics, with compositions of x = 0.02, 0.03, 0.04 and 0.05. Fine grains indicated a cubic structure, whereas large ones indicated a tetragonal structure. Regarding the dielectric property, Curie temperature decreased with increasing BMN content, whereas the er value increased until the BMN content reached 3 mol% before dropping to a lower value. Copyright © 2013 Taylor & Francis Group, LLC.