Browsing by Author "Pojprapai, Soodkhet"

Now showing 1 - 5 of 5
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    CNTs-added PMNT/PDMS flexible piezoelectric nanocomposite for energy harvesting application
    (Taylor and Francis, 2018-04-05) Promsawat, Napatporn; Promsawat, Methee; Janphuang, Phatthanapong; Beeby, Steve; Rojviriya, Catleya; Pakawanit, Phakkhananan; Pojprapai, Soodkhet; Luo, Zhenhua
    The flexible piezoelectric nanocomposites based on lead magnesium niobate titanate [Pb(Mg1/3Nb2/3)0.65Ti0.35O3; PMNT] particles in polydimethylsiloxane (PDMS) matrix were fabricated and characterized. PMNT powders are synthesized using the columbite precursor method. PMNT/PDMS flexible nanocomposites are then prepared by spin casting technique, where a small amount of carbon nanotubes (CNTs) is added into the PMNT/PDMS composite to enhance cross-links between PMNT particles and PDMS matrix. The phase and microstructure of the nanocomposite are investigated by using X-ray diffraction and scanning electron microscope (SEM). The electromechanical behavior is evaluated by using an autonomous pneumatic actuator. The flexible composite, occupying approximately 300 mm2, is capable of generating an open-circuit voltage (Voc) of 2.83 ± 0.24 V and a short-circuit current (Isc) signal of 0.33 ± 0.01 µA across 10 Ω resistor under mechanical load of 300 N. The generated electrical charges are 29026 pC. The relative dielectric constant is measured at 10 kHz and found to be 6.76 ± 1.15. The piezoelectric PMNT/PDMS composite can potentially be used in a variety of applications such as wearable sensors, actuators, and energy harvesting for converting kinetic energy into useful electrical energy.
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    Effects of frequency on electrical fatigue behavior of ZnO-modified Pb(Mg1/3Nb2/3)0.65Ti0.35O3 ceramics
    (Elsevier, 2017-07-08) Promsawat, Methee; Promsawat, Napatporn; Wong, Jenny W.; Luo, Zhenhua; Pojprapai, Soodkhet; Jiansirisomboon, Sukanda
    This work aims to study the effects of frequency on the electrical fatigue behavior of ZnO-modified Pb(Mg1/3Nb2/3)0.65Ti0.35O3 (PMNT) ceramics. Changes in microstructures, ferroelectric and piezoelectric properties of the ceramics at bipolar electrical fatigue frequencies of 5, 10, 50 and 100 Hz were observed. The thickness of damaged surface of the ceramics decreased with increasing frequency. The degradation of properties of the ceramics fatigued at low frequency was greater than those fatigued at high frequency. The degradation by electrical fatigue at lower frequencies, 5 and 10 Hz, could be caused by the effects of both field screening and domain pinning, while at higher frequencies the fatigue was mainly a result of the field screening effect. The fatigue properties of ZnO-modified PMNT ceramics was compared to Pb-based and Pb-free ferroelectric ceramics. It was found that the fatigue endurance of ZnO-modified PMNT ceramic was greater than that of hard PZT ceramic but less than that of Pb-free ferroelectric ceramic.
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    Effects of temperature on aging degradation of soft and hard lead zirconate titanate ceramics
    (Elsevier, 2017-04-26) Promsawat, Methee; Marungsri, Boonruang; Promsawat, Napatporn; Janphuang, Pattanaphong; Luo, Zhenhua; Pojprapai, Soodkhet
    This paper aims to study the effects of heat treatment temperatures on the aging degradation of piezoelectric properties, i.e. piezoelectric coefficient (d33) and planar electromechanical coupling factor (kp), in soft and hard PZT ceramics. Aging degradations of d33 and kp of the samples were measured for 192 h prior to heat treatments. The samples were then treated at various temperatures equivalent to 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 times of the materials' Curie temperatures. Aging degradations of d33 and kp of the heat-treated samples were observed continuously for 1128 h. The piezoelectric properties of the un-treated samples gradually decreased with aging time. Attenuation of d33 and kp in the samples immediately after heat treatment increased with increasing heat treatment temperature. Moreover, aging degradation rate and relaxation time of the samples measured after heat treatments increased with increasing heat treatment temperature. Comparing to hard PZT ceramics, soft PZT demonstrated greater change of d33 and kp immediately after heat treatments. Soft PZT also showed greater aging rate and aging time than those of hard PZT. From the overall results, it can be concluded that both material type and heat treatment temperature have effects on aging behaviors of PZT materials. Aging degradation was more pronounced in soft PZT and the samples treated at high temperatures. The observed aging behaviors of PZT materials were explained by the interaction between domains and defects of oxygen vacancies that leads to volume, domain and grain boundary effects.
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    Investigation of the effect of temperature on aging behavior of Fe-doped lead zirconate titanate
    (World Scientific Publishing, 2017-03-29) Promsawat, Napatporn; Promsawat, Methee; Janphuang, Pattanaphong; Marungsri, Boonruang; Luo, Zhenhua; Pojprapai, Soodkhet
    The aging degradation behavior of Fe-doped Lead zirconate titanate (PZT) subjected to different heat-treated temperatures was investigated over 1000 h. The aging degradation in the piezoelectric properties of PZT was indicated by the decrease in piezoelectric charge coefficient, electric field-induced strain and remanent polarization. It was found that the aging degradation became more pronounced at temperature above 50% of the PZT’s Curie temperature. A mathematical model based on the linear logarithmic stretched exponential function was applied to explain the aging behavior. A qualitative aging model based on polar macrodomain switchability was proposed.
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    A study of the electrical fatigue behavior of lead zirconate titanate for micro-actuator application in hard disk drives
    (Taylor and Francis, 2021-03-16) Luo, Zhenhua; Kampoosiri, Sirirat; Sonklin, Thita; Jongpinit, Watcharin; Marungsri, Boonruang; Pojprapai, Soodkhet
    This research work reports the effect of electric field amplitude on fatigue behavior of lead zirconate titanate ceramics (PZT) for micro-actuator hard disk drive application. The soft PZT samples were subjected to bipolar electrical cyclic loads to study the fatigue behavior. The amplitudes of electric fields of 1.00, 1.25, and 1.50 kV/mm at 10 Hz of frequency were applied. Polarization-electric field (PE) loops representing fatigue degradation were demonstrated. The fatigue behavior was indicated by the alternation of the size and shape of PE loops and remanent polarization (Pr). It was found that the remanent polarization decreased significantly with the number of loading cycles. Fatigue degradation was more pronounced in greater applied field. A mathematical model for fatigue degradation was proposed in this work.