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Author: search.filters.author.Makcharoen, WorawutSubject: search.filters.subject.Dielectric properties

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    Electrical and dielectric properties of barium titanate–polydimethylsiloxane nanocomposite with 0-3 connectivity modified with carbon nanotube (CNT)
    (2019-01-02)
    Nawanil, Chanisa
    ;
    Makcharoen, Worawut
    ;
    Khaosa-Ard, Krittanat
    ;
    Maluangnont, Tosapol
    ;
    Vittayakorn, Wanwilai
    This study explored the preparation and electrical properties of 0–3 barium titanate/polydimethylsiloxane nanocomposites by dispersing barium titanate nanoparticles (BaTiO<inf>3</inf>; BT) into the polydimethylsiloxane (PDMS) matrix phase. The effect of barium titanate nanoparticles on electrical properties has been investigated systematically, and the relative permittivity of nanocomposites was found to increase significantly with increasing barium titanate content. Different theoretical models were used to predict the dielectric constant of these composites and compare their experimental value with the theoretical value in order to find an appropriate equation. The result indicated that the dielectric properties of composites are influenced not only by relative permittivity of the components but also dependence on interactions between ceramics and polymers. Furthermore, the preparation and dielectric properties of BT/PDMS nanocomposites modified with carbon nanotube (CNT) were also studied. The dielectric results demonstrate that adding CNT can enhance the relative permittivity of the BT/PDMS composite via improvement of dispersion and distribution of the BT nanoparticles in the PDMS matrix phase. Moreover, the electrical outputs from the BT/PDMS/CNT nanocomposites generator were measured under periodic knocking. The nanocomposites innovatively expand the feasibility of self-powered energy systems for smart sensor and energy harvesting applications.
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    Dielectric Relaxation and Microstructures of SnO2 Doped CaCu3Ti4O12 Electroceramics Prepared Via Vibro-milling Method
    (2017-01-01)
    Makcharoen, Worawut
    ;
    Punsawat, Woratat
    High dielectric constant CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) is a compound with a high dielectric constant, but it has a high loss tangent at room temperature. This research aims to study on the dielectric properties and loss tangent of SnO<inf>2</inf> doped CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) ceramics were investigated. The ceramic samples of SnO<inf>2</inf> doping CCTO were prepared by a solid-state reaction method. The characterization of the samples was carried out using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The conventional solid-state reaction was employed. The metal oxide powders were mixed using a vibratory milling for 6 hour and sintered at 1000°C for 4 hour. The phase formation of the calcined powders and sintered ceramics was examined by X-ray diffraction technique (XRD). Microstructure was examined by scanning electron microscopy (SEM). SnO<inf>2</inf> doping produced a notable decrease in grain size. Average values of grain size, as measured by the linear intercept method. The dielectric measurements at room temperature to 130°C, in the frequency range 100 Hz- 500 kHz. The XRD result a CCTO structure does not changes on Sn doped samples. The results show the loss tangent at room temperature and at 100 kHz decreased from 0.14 for the 0 mol% Sn doped CCTO sample to 0.04 for the 2.0 mol% Sn doped sample while at 500 kHz, it was decreased from 0.2 for the undoped CCTO sample to 0.04 for the 2.0 mol% Sn doped sample. However, the lowest loss tangent was 0.02 at 500 kHz and at 65°C and show a stable loss tangent in temperature range 25 - 130°C.
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    Effect of platinum substitution on the microstructures and dielectric relaxation of CaCu3Ti4O12 ceramics
    (2013-10-29)
    Makcharoen, Worawut
    The CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) has the advantage for the various applications especially for capacitive elements in microelectronic devices over the ferroelectric materials including BaTiO<inf>3</inf>. CCTO is a ceramic compound with a high dielectric constant but it has a high loss tangent at room temperature. In this work, the Influences of PtO<inf>2</inf> doping on the dielectric properties of CaCu<inf>3</inf>Ti<inf>4</inf>O<inf>12</inf> (CCTO) ceramics were investigate. The ceramics CCTO and PtO<inf>2</inf> doping CCTO were studied by Xray diffraction, scanning electron microscopy. The dielectric properties have been measured as a function of temperature and frequency range 0.1 - 500 kHz. The XRD shows the CCTO structure does not changes after doping with platinum. The results show that PtO<inf>2</inf> doped can reduce the mean grain sizes of CCTO, but the dielectric constant still remained a height. The samples of 2.0 mol% Pt-doped have exhibited high dielectric constant of about 22,000 and the loss tangent about 0.7 at room temperature and frequency at 10 kHz. The reduced of the loss tangent could be interpreted with the internal barrier layer capacitor model (IBLC) © (2013) Trans Tech Publications, Switzerland.