Electrical Behaviors of (1-x)BZT07-xBNWT Lead Free Solid Solution Binary System

Gobwute Rujijanagul,Chatchai Kruea-In 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.4

Solid solutions of the (1-x)Ba(Zr0.07Ti0.93)O3-xBa((Ni0.5W0.5)0.1Ti0.9)O3 system with 0.05 ≤ x ≤ 0.2, were fabricated via a solid-state reaction technique. All samples exhibited a pure phase perovskite structure. The x = 0.05samples exhibited very high dielectric constants (>60,000) for temperatures over 400°C, while the x = 2.0samples had a higher degree of dielectric constant stability over a wide temperature range. The ceramics also showed a dielectric relaxor behavior. The frequency dependence of the loss tangent peak was observed to follow an Arrhenius law where the activation energies increased with increasing Ba((Ni0.5W0.5)0.1Ti0.9)O3content. The result suggests that the addition of Ba((Ni0.5W0.5)0.1Ti0.9)O3 has strong effects on the properties this ceramic system.

Influence of graphite particle size on electrical properties of modified PZT-polymer composites

Gobwute Rujijanagul,Saowakhon Jompruan,Arnon Chaipanich 한국물리학회 2008 Current Applied Physics Vol.8 No.3,4

Piezoceramicspolymer composites using modied lead zirconate titanate (Pb0.88Sr0.12Zr0.54Ti0.44Sb0.02O₃) and polyethylene (PE)were prepared by a calendaring method. The modied ceramic powder was prepared by a conventional solid-state method. Graphitepowder of various particle sizes was also added into the composites. Properties of the composites as a function of particle sizes of the ceramics and graphite were studied. The relative permittivity and piezoelectric coefficient (d₃₃) of the composites were found toincrease with increasing the particle size of the modied ceramics. Composites contained ner graphite particle also found to give higherd₃₃ values.

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.

Dielectric Properties of (1-x)SrFe1/2Nb1/2O3-xBaZn1/3Ta2/3O3 Ceramics

Thanatep Phatungthane,Gobwute Rujijanagul 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.4

In this work, (1-x)SrFe1/2Nb1/2O3-xBaZn1/3Ta2/3O3 ((1-x)SFN-xBZT) ceramics with 0.02 ≤ x ≤ 0.11 were synthesized via a solid state reaction method. A phase formation analysis using the x-ray diffraction technique (XRD) showed that the ceramic samples exhibited a pure phase perovskite for x ≤ 0.10 compositions, indicating that the solubility limit of BZT in SFN is very low. Adding BZT enhanced the dielectric constant and reduced the dielectric loss. Very high dielectric constants (>40,000) were observed for the x = 0.10 samples. The dielectric property investigation also revealed that all samples exhibited dielectric relaxor behavior.

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.

The improvement in dielectric and ferroelectric performance of PZT??PZN ceramics by thermal treatment

Naratip Vittayakorn,Gobwute Rujijanagul,David P. Cann 한국물리학회 2007 Current Applied Physics Vol.7 No.5

Pyrochlore-free lead zirconate titanate lead zinc niobate ceramics have been systematically investigated in the as-sintered conditionas well as after annealing. The ceramics were characterized by dielectric spectroscopy and SawyerTower polarization (PE) measure-ments. The powders of Pb[(Zr1/2Ti1/2)(1. x)(Zn1/3Nb 2/3)x]O3, wherex = 0.1, 0.3 and 0.5 were prepared using the columbite(wolframite)precursor method. The general trend seems to indicate that the annealed samples become more normal-ferroelectric-like behavior asopposed to the relaxor-ferroelectric-like behavior observed in the as-sintered state. The as-sintered 0.9PZT0.1PZN ceramic exhibitedweak relaxor-ferroelectric behavior, with a relatively low dielectric constant maximum of 14,000 measured at 1 kHz. Annealing resultedin a transition to normal-ferroelectric-like behavior, a shift in the dielectric maximum temperature from 360.C to 350.C, and a dramaticincrease in the dielectric constant at 1 kHz to a maximum value of 35,000 for the longer anneal. After thermal annealing at 900.week a strong enhancement of remanent polarization (Pr) was observed.

Enhanced piezoelectric properties near the morphotropic phase boundary in lead-free (1-x)(Bi0.5K0.5)TiO3-xBi(Ni0.5Ti0.5)O3 ceramics

Parkpoom Jarupoom,Pharatree Jaita,Rattikorn Yimnirun,Gobwute Rujijanagul,David P. Cann 한국물리학회 2015 Current Applied Physics Vol.15 No.11

Lead-free piezoelectric ceramics of the composition (1-x)(Bi0.5K0.50)TiO3-xBi(Ni0.50Ti0.50)O3 or (1-x)BKTxBNiT (when x = 0-0.20 mol fraction) were prepared by a conventional mixed-oxide method and sintered at 1050 ℃ for 4 h. The effects of BNiT content on the phase equilibria, and the dielectric, ferroelectric and piezoelectric properties were systematically investigated. High density sintered specimens (5.71-6.12 g/cm3) were obtained for all compositions. X-ray diffraction patterns showed that all BKTBNiT samples exhibited a single perovskite phase which confirms that BNiT and BKT formed a solid solution up to x = 0.20. A morphotropic phase boundary (MPB) separating a BKT-rich tetragonal phase and a BNiT pseudo-cubic phase was identified over the compositional range 0.05 < x < 0.10, where enhanced electrical properties were observed. The optimum dielectric properties (εr = 1710, tand = 0.036), ferroelectric properties (Pr = 16.6 mC/cm2, Ec = 22.5 kV/cm and Rsq = 0.86) and piezoelectric properties (d33 = 288 pC/N, Smax = 0.22% and d* 33 = 313 pm/V) were observed with a relatively high Tm ~ 304 ℃ within this MPB region. Overall, these results indicate that the BKT-BNiT ceramic system is a promising lead-free piezoelectric candidate for further development for actuator applications.

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℃.

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.

Development of perovskite and phase transition in lead cobalt niobate modified lead zirconate titanate system

Naratip Vittayakorn,Supamas Wirunchit,Sakda Traisak,Rattikorn Yimnirun,Gobwut Rujijanagul 한국물리학회 2008 Current Applied Physics Vol.8 No.2

Ferroelectric lead zirconate titanatelead cobalt niobate ceramics with the formula (1. x)Pb(Zr1/2Ti1/2)O3xPb(Co1/3Nb 2/3)O3 wherex = 0.00.5 were fabricated using a high temperature solid-state reaction method. The formation process, the structure and homogeneityof the obtained powders have been investigated by X-ray diraction method as well as the simultaneous thermal analysis of both dier-ential thermal analysis (DTA) and thermogravimetry analysis (TGA). It was observed that for the binary system (1. x)Pb(Zr1/2-Ti1/2)O3xPb(Co1/3Nb 2/3)O3, the change in the calcination temperature is approximately linear with respect to the PCoN content inthe rangex = 0.00.5. In addition, X-ray diraction indicated a phase transformation from a tetragonal to a pseudo-cubic phase whenthe fraction of PCoN was increased. The dielectric permittivity is remarkably increased by increasing PCoN concentration. The maxi-mum value of remnant polarizationPr (25.3l C/cm2) was obtained for the 0.5PZT0.5PCoN ceramic.