Wirunchit, Supamas

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Wirunchit, Supamas
Alternative Name
Wirunchit, S.
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Email
supamas.wi@kmitl.ac.th

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    Item type:Publication,
    Physical properties and phase transitions in perovskite Pb[Zr 1-x(Ni1/3Nb2/3)x]O3 (0.0 ≤ x ≤ 0.5) ceramics
    (2008-06-21)
    Wirunchit, Supamas
    ;
    Laoratanakul, Pitak
    ;
    Vittayakorn, Naratip
    A solid solution of lead zirconate-lead nickel niobate ceramics, Pb[Zr <inf>1-x</inf>(Ni<inf>1/3</inf>Nb<inf>2/3</inf>)<inf>x</inf>]O<inf>3</inf> (PZNN) with x = 0.0-0.5, was synthesized via the columbite precursor method. The crystal structures as well as the thermal and dielectric properties were investigated in terms of the lead nickel niobate (PNN) concentration. X-ray diffraction indicated that all samples exhibited a single-phase perovskite structure. At room temperature, Pb[Zr<inf>1-x</inf>(Ni<inf>1/3</inf>Nb <inf>2/3</inf>)<inf>x</inf>]O<inf>3</inf> is orthorhombic for a composition where x = 0, rhombohedral for the compositions where x = 0.1, 0.2 and 0.3 and pseudo-cubic for compositions where x = 0.4 and 0.5. The results of the addition of lead nickel niobate to the lead zirconate ceramic showed enhancement of the room-temperature dielectric permittivity. Lead nickel niobate substitution also led to lower transition temperatures. Furthermore, this transition from normal to relaxor FE ceramics was typified by a quasi-linear relationship between the diffuseness parameter δ<inf>γ</inf> and the PNN mole fraction x. © 2008 IOP Publishing Ltd.
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    Item type:Publication,
    Preparation of lead zirconate-lead nickel niobate ceramics by the reaction sintering process
    (2009-12-01)
    Wirunchit, Supamas
    ;
    Muanghlua, Rangson
    ;
    Niemcharoen, Surasak
    ;
    Vittayakorn, Wanwilai C.
    ;
    Laoratanakul, Pitak
    The perovskite structure of lead zirconate - lead nickel niobate ceramics, (1-x) PbZrO3-xPb(Ni1/3Nb2/3)O3 (PZ - PNN) at x between 0.00-0.50, has been prepared by the reaction-sintering process. The specimens were prepared directly from a mixture of their constituent oxide without any calcination step. The PZ - PNN ceramics could be obtained after 6 h sintering at 1,100-1,250°C. Crystal structure and phase transition of PZ-PNN were investigated by x-ray diffraction (XRD). XRD indicated that the structure of PZ-PNN ceramics is orthorhombic for a composition where x = 0.00, rhombohedral for compositions where x = 0.10 ≤ x ≤ 0.40 and pseudo-cubic for a composition where x = 0.50. The dielectric properties of the ceramics were measured as functions of both temperature and frequency. The results indicated that the transition temperature decreases with increasing PNN concentration. Furthermore, morphology and grain size evolution have been determined via a scanning electron microscope (SEM). Copyright © Taylor & Francis Group, LLC.