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PHASE FORMATION AND ELECTRICAL PROPERTIES OF BCLTS CERAMICS SYNTHESIZED VIA THE SOLID-STATE COMBUSTION TECHNIQUE
(2025-01-01)
Somsri, Widchaya
;
Charoenthai, Nipaphat
;
Sutthapintu, Aekkasit
;
Noisak, Jitrawan
;
Vittayakorn, Naratip
Lead-free Ba<inf>0.93</inf>Ca<inf>0.04</inf>La<inf>0.03</inf>Ti<inf>0.90</inf>Sn<inf>0.10</inf>O<inf>3</inf> (BCLTS) ceramics were fabricated via solid-state combustion technique. The BCLTS powders were calcined in a temperature range of 1075-1175°C for 2h and sintered in a temperature range of 1350-1450°C for 2h. The BCLTS powders exhibited a pure perovskite phase when calcined above 1150°C. All BCLTS ceramic samples displayed a perovskite structure with coexisting cubic and tetragonal phases, with a secondary phase observed only at 1450°C. The growth of grain size was increased with increasing sintering temperature (0.42 to 0.65 μm.). The highest dielectric and ferroelectric properties (ε<inf>r</inf>=3047, tan δ<inf>r</inf> = 0.029, P<inf>max</inf> = 9.52 μC/cm2, P<inf>r</inf> = 0.48 μC/cm2, E<inf>c</inf>= 1.04 kV/cm) were obtained at the sintering temperature of 1400°C. The altered phase structure in this research, compared to earlier studies, results in distinct outcomes for the dielectric and ferroelectric properties.
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The role of γ-C2H5NO2 as a new transient liquid phase in cold sintering process of BaTiO3 composites
(2024-07-01)
Noisak, Jitrawan
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Ieamviteevanich, Pimchanok
;
Charoonsuk, Thitirat
;
Pakawanit, Phakkhananan
;
Pinpru, Nattapong
Dielectric materials, such as barium titanate (BT)-based materials, have excellent dielectric properties but require high temperatures (above 1300 °C) for ceramic fabrication, leading to high costs and energy loss. The cold sintering process (CSP) offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route. In this work, we proposed an alternative organic ferroelectric phase, gamma-glycine (γ-GC), which acts as a transient liquid phase to fabricate high-density composites with barium titanate (BT) at low temperatures through CSP. Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6% when it was sintered at 120 °C for 6 h under 10 MPa uniaxial pressure. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) mappings of the composite suggested that γ-GC completely underwent the precipitation–dissolution process and, therefore, filled between BT particles. Moreover, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the preservation of γ-GC without undesired phase transformation. In addition, the ferroelectric and dielectric properties of γ-GC/BT composites have been reported. The high dielectric constant (ε<inf>r</inf>) was 3600, and the low dielectric loss (tanδ) was 1.20 at 200 °C and 100 kHz for the 15γ-GC/85BT composite. The hysteresis loop showed a remanent polarization (P<inf>r</inf>) of 0.55 µC·cm-2 and a coercive field (E<inf>c</inf>) of 7.25 kV·cm-1. Our findings reaffirmed that an organic ferroelectric material (γ-GC) can act as a transient liquid phase in a CSP that can successfully and sustainably fabricate γ-GC/BT composites at low temperatures while delivering outstandingly high performance.
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Towards the preparation of organic ferroelectric composites: fabrication of a gamma-glycine-bacterial cellulose composite via cold sintering process
(2023-07-01)
Noisak, Jitrawan
;
Charoonsuk, Thitirat
;
Pongampai, Satana
;
Pinpru, Nattapong
;
Pakawanit, Phakkhananan
The cold sintering process (CSP) has emerged as a revolutionary technique for low-temperature processing of ceramics and composites, enabling high-density fabrication at low temperatures. In this study, we demonstrated the implementation of CSP in fabricating the γ-glycine (γ-G)-bacterial cellulose (BC) composite and evaluated the effect of sintering temperature and holding time on the microstructure and electrical properties. Our findings revealed that an increase in sintering temperature and holding time leads to grain growth, as the transient solvent (water) facilitates the closely-packed microstructure. Moreover, the addition of BC as a filler into the γ-G matrix leads to a composite with a 10% increase in hardness when BC was uniformly distributed in γ-G. The composite with a relative density of 97% was successfully obtained at 120 °C/24 h, preserving the γ polymorph of glycine without the unwanted transformation commonly observed with traditional sintering. We also reported the dielectric and ferroelectric properties of the γ-G-BC composite, exhibiting a remanent polarization of 0.004 μC/cm2 and a coercive field of 1.201 kV/cm. Our findings suggest that CSP is a promising approach for low-temperature processing and fabrication of ceramics, especially when incorporating structurally sensitive filler such as organic ferroelectric, to achieve high-performance composites.
1
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Silk Fibroin/Amino Acid Hybrid Organic Piezoelectric-Triboelectric Nanogenerator
(2023-01-01)
Suktep, Natdanai
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Pongampai, Satana
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Pakawanit, Phakkhananan
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Noisak, Jitrawan
;
Bongkarn, Theerachai
Triboelectric nanogenerators (TENG) with great performance and biodegradability are desired for the expansion of novel medical devices and wearable electronics. The present study aims at the preparation of natural silk in the form of silk fibroin (SF) film for utilization in TENG and further improving its output efficiency by embedding organic-piezoelectric gamma-glycine (γ-gly) amino acid to be a hybrid-organic piezoelectric/triboelectric nanogenerator (HO-P/TENG). The attenuated total reflectance infrared spectroscopy (ATR-IR) results demonstrated the N-H, C = O, and C-N bonding for SF and SF/γ-gly, confirming its dominant effect with a strong electron-donating tendency from those amino groups. The scanning electron microscope (SEM) and synchrotron radiation X-ray tomographic microscopy (SR-XTM) images show good dispersibility of incorporated γ-gly on the surface and also inside the SF matrix relating to its content to improve the electrical performance homogeneously. By fabricating the device in the vertical contact-separation mode, the present SF/γ-gly HO-P/TENG at 15 wt% provides the maximum output voltage (V<inf>OC</inf>) and current (I<inf>SC</inf>) of 81 V and 121 μA with a maximum output power (P<inf>max</inf>) of 205 μW at the external load resistance of 5 MΩ. This SF-based HO-P/TENG has the advantage of being cost-effective with simple fabrication, demonstrating great promise for practical uses.
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