Electrical properties and phase transition behaviors of Sr-doped 0.8PZT_0.2PNN ceramics

Sukum Eitssayeam,Gobwute Rujijanagul 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

Dielectric properties and phase transition behaviors of Sr-doped 0.8PbZr₁/₂Ti₁/₂O₃-0.2PbNi₁/₃Nb₂/₃O₃ ceramics have been investi-gated. The ceramics were prepared by a normal solid-state method. For undoped sample, very high relative permittivity >30,000 (at1 kHz) was observed at the transition temperature of 278℃. With increasing Sr concentration, the degree of diuse phase transitionwas enhanced and a linear reduction in the transition temperature was produced.

Ferroelectric, pyroelectric and dielectric properties of complex perovskite-structured Pb0.84Ba0.16(Zr0.44Ti0.40Fe0.08Nb0.08)O₃ ceramics

Sukum Eitssayeam,Uraiwan Intatha,Kamonpan Pengpat,Gobwute Rujijanagul,Kenneth J.D. MacKenzie,Tawee Tunkasiri 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

Relaxor ferroelectrics with A'A"(B'B")O₃- type perovskite structures have attracted much attention because of their excellent dielec-tric and electromechanical properties. The physical properties or device parameters of PZT can be tailored by improved synthesis andprocessing techniques and by making suitable substitutions into the A and/or B sites. In this study, Pb0.84Ba0.16(Zr0.44Ti0.40-Fe0.08Nb 0.08)O₃ ceramics were prepared by solid state reaction and the eect of the processing parameters on the ferroelectric, dielectricand pyroelectric properties was determined. Optimal dielectric properties were achieved in Pb0.84Ba0.16(Zr0.44Ti0.40Fe0.08Nb 0.08)O₃ ceramics by calcination at 1100.C and sintering at 1250℃. Hysteresis loop measurements of these materials indicated a remanent polarization(Pr) and spontaneous polarization (Ps) of 15.88 μC/cm² and 26.29 μC/cm², respectively. TEM micrographs showed nano-domains in thecalcined powder conrming their ferroelectric properties. The dielectric properties also show ferroelectric behavior, with a Curie temper-ature of approximately 220℃. The values ofpi show a continuous increase with increasing temperature up to a maximum value. 800 nC/cm² K at~120℃.

Impedance study of giant dielectric permittivity in BaFe0.5Nb0.5O3 perovskite ceramice

Uraiwan Intatha,Sukum Eitssayeam,John Wang,Tawee Tunkasiri 한국물리학회 2010 Current Applied Physics Vol.10 No.1

Single-phase BaFe0.5Nb0.5O3 (BFN) ceramics were prepared by solid-state reaction method and were characterized by X-ray Diffraction (XRD) technique. Then, impedance spectroscopy measurements were conducted in a frequency range from 100 Hz to 1 MHz and in a temperature range from 293 to 600 K. Relaxation phenomena of non-Debye type have been observed in the BFN ceramics, as confirmed by the Cole–Cole plots. The higher values of e0 at the lower frequencies are explained on the basis of the Maxwell–Wagner (MW) polarization model. Complex impedance analysis enables us to separate the contributions from grains and grain boundaries of our samples. We found that at higher temperatures grain boundary resistance is higher than grain resistance, irrespective of composition.

Morphology of Potassium Sodium Niobate based Silicate Glass System

Ploypailin Yongsiri,Sukum Eitssayeam,Somnuk Sirisoonthorn,Kamonpan Pengpat 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.6

In this research, the fabrication of lead-free ferroelectric glass-ceramics from the (K0.5Na0.5)NbO3 system via incorporation method was carried out. For the incorporation method, calcined KNN was added into glass batches as a heterogeneous nucleating agent. Glass-ceramics KNNs were prepared from two compositions of KNN-SiO2with a ratio of 75 : 25 (C1) and 80 : 20 (C2) mol.%. Thermal properties resulting from DTA showed samples C1and C2 having glass transition temperatures of 532°C and 520°C and crystallization temperatures of 645°C and 620°C, respectively. The prepared glasses were subsequently subjected to a heat treatment schedule in a temperature range of 500°C - 575°C for crystallization. XRD results showed that the KNN phase occurred in C1. The C2 glass-ceramic samples contained unidentified phases together with the KNN phase. From SEM observation,it was found that bulk crystals with an equiaxed shape of KNN phase dispersed well in all glass-ceramic matrices. Crystal sizes increased with increasing heat treatment temperatures. In C2 glass-ceramics, unidentified phases were found together with the KNN phase.

Influence of Seed Nano-Crystals on Electrical Properties and Phase Transition Behaviors of Ba0.85Sr0.15Ti0.90Zr0.10O3 Ceramics Prepared by Seed-Induced Method

Krit Sutjarittangtham,Uraiwan Intatha,Sukum Eitssayeam 대한금속·재료학회 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.3

This work studied the effects of seed nano-crystal on the electrical properties and the phase transition behaviors of Ba0.85Sr0.15Ti0.90Zr0.10O3 (BSZT) ceramics. The BSZT ceramics were prepared by the seed-induced method. The seed nano-crystal were prepared by the molten salt technique, and NaCl-KCl (1:1 by mole) eutectic mixtures were used as the flux.[1] The ceramic powders were prepared by using a conventional method which added seed nano-crystals at various ratios. Results indicated that seed nano-crystals enhanced the electrical properties of ceramics. The sample with a 20 wt.% seed nano crystals has excellent value of dielectric constant (εr) of 34698 at maximum temperature. The phase transition temperature was observed at 60°C. The morphology was found that the grain size increasing significantly with an increased of seed nano crystals. The relaxor ferroelectric phase transition behavior was shown by a diffuseness parameter (γ). An increase in the BSZT-seed showed a decreased in g value from 1.61 to 1.44. Thus the ferroelectric of the BSZT ceramics can be confirmed by hysteresis loop.

Effects of NiO Nanoparticles on Electrical and Magnetoelectric Properties of BNT Based Ceramics

Chatchai Kruea-In,Thitima Glansuvarn,Sukum Eitssayeam,Kamonpan Pengpat,Gobwute Rujijanagul 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.6

The properties of 0.94BNT-0.06BT/xNiO lead-free nanocomposites were investigated. The NiO additive influenced dielectric properties as well as the phase transition behavior of the samples. Dielectric properties under applied magnetic fields were also measured. After addition of the additive, the loss tangent could be controlled by an applied magnetic field. Furthermore, the P-E hysteresis loop changed from a normal hysteresis loop for the unmodified sample to a constricted loop for the x = 0.5 and 1.0 vol. % samples, and then became a lossy capacitor hysteresis loop for the x = 2.0 vol. % sample. These results suggest that NiO nanoparticles have a strong influence on the properties of the composites.

Dielectric and impedance measurements on (1-x)Ba(Fe1/2Ta1/2) O3-xBa(Zn1/3Ta2/3)O3 ceramics

Thanatep Phatungthane,Gobwute Rujijanagul,Kamonpan Pengpat,Sukum Eitssayeam,Tawee Tunkasiri,Luiz F. Cotica,Ruyan Guo,Amar S. Bhalla 한국물리학회 2014 Current Applied Physics Vol.14 No.12

In this work, ((1x)Ba(Fe1/2Ta1/2)O3-xBa(Zn1/3Ta2/3)O3), ((1x)BFT-xBZT) ceramics with x ¼ 0.00e0.12 were synthesized by the solidestate reaction method. X-ray diffraction data revealed that both the powders and ceramics were of a pure-phase cubic perovskite structure. All ceramics showed large dielectric constants. For the x ¼ 0.12 sample, a very high dielectric constant (>20,600) was observed. A lowering in the dielectric loss compared to pure BFT ceramics was observed with the BZT addition. The impedance measurements indicated that BZT has a strong effect on the bulk grain and grain boundary resistance of BFT ceramics. These results are in agreement with the measured dielectric properties. Based on dielectric and impedance results, (1x)BFT-xBZT ceramics could be of great interest for high performance dielectric materials applications due their giant dielectric constant behavior.

PVA/PVP K90 Nanofibers Containing Punica granatum Peel Extract for Cosmeceutical Purposes

Nachtharinee Laosirisathian,Chalermpong Saenjum,Jakkapan Sirithunyalug,Sukum Eitssayeam,Wantida Chaiyana,Busaban Sirithunyalug 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1

This study aimed to develop, characterize, and investigate the cosmeceutical activities and irritation properties ofPunica granatum peel extract (PE) loaded nanofibers. Nanofibers from polyvinyl alcohol (PVA) and polyvinylpyrrolidone(PVP K90) were prepared using an electrospinning technique and characterized by scanning electron microscope, Fouriertransform infrared spectroscopy, X-ray diffractometer, differential scanning calorimeter, and tensile tester. The content of PEloaded in nanofibers were investigated using high-performance liquid chromatography. PE loaded nanofibers wereinvestigated for antioxidant activities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay. Anti-tyrosinase was determined by spectrophotometric method. The cytotoxicity and irritationproperties were determined by WST-1-based cell cytotoxicity assay and hen’s egg test chorioallantoic membrane assay,respectively. The results remarked that 2.5 % w/v PE loaded in nanofiber containing 10 % w/v PVA and 2 % w/v PVP K90(N2) were uniform with the mean diameter of 493.9±91.6 nm. The amorphous form of nanofibers was detected and around94 % w/w of PE was entrapped. Additionally, N2 showed the most suitable mechanical properties and possessed thesignificantly highest antioxidant and anti-tyrosinase activities. Notably, it was safe since it had no cytotoxicity and noirritation. Therefore, PE loaded nanofibers were attractive and suggested for cosmeceutical applications.