Influence of Currents and Electric Fields in YNMO Ceramics

2017 ◽  
Vol 866 ◽  
pp. 256-258
Author(s):  
Naphat Albutt ◽  
Suejit Pechprasarn ◽  
Thanapong Sareein

Development of ceramic materials is critical for new and improved electronic applications. Herein, the J-E response of Y2NiMnO6 (YNMO) ceramics composited by a solid state reaction method was investigated. Sintering temperature and time were found to have significant influence on the ceramics electrical properties. In particular, higher temperatures and longer sintering times resulted in more favourable dielectric properties of the YNMO ceramics. A current of 40 mA/cm2 at 20,000 mV/cm was obtained by sintering at 1300 °C for 12 hours, whereas a current of 9 mA/cm2 at 4000 mV/cm can be achieved by sintering at 1400 °C for 24 hours. These results will be useful for identifying applications for YNMO ceramics. The electrical properties of the YNMO ceramics can be tuned for different electronic components such as dry batteries and capacitors.

2013 ◽  
Vol 675 ◽  
pp. 200-204
Author(s):  
Fei Shi ◽  
Peng Cheng Du ◽  
Jing Xiao Liu ◽  
Ji Wei Wu ◽  
De Qing Chen ◽  
...  

The Mg2SiO4-MgTiO3-CaTiO3 composite dielectric ceramics with different Mg2SiO4 addition amounts were prepared by solid state reaction method. The effects of Mg2SiO4 addition amounts on the microstructure and dielectric properties as well as sintering temperature of xMg2SiO4-(0.95-x)MgTiO3-0.05CaTiO3 (abbreviated as xMSTC, 0.25≦x≦0.75) composite ceramics were investigated. The results indicated that the sintering temperature of MgTiO3-CaTiO3 based ceramics with Mg2SiO4 addition could be lowered effectively to 1320~1340°C, and the dielectric constant decreased and dielectric loss increased gradually with the increase of Mg2SiO4 content. The 0.45MSTC ceramics containing 45 wt% Mg2SiO4 and sintered at 1340°C showed desirable dielectric properties with dielectric constant εr=13.3,dielectric loss tanδ=4.5×10-4 and temperature coefficient of relative permittivity τε =10 ppm/°C.


2016 ◽  
Vol 690 ◽  
pp. 162-166 ◽  
Author(s):  
Uraiwan Intatha ◽  
Krit Sujarittangtham ◽  
Sukum Eitssayeam

A solid-state reaction method is generally used to fabricate ceramics. This work studies the influence of heterogenous nano-crystallites on electrical properties of lead free Na0.47K0.47Li0.06NbO3 (NKLN) ceramics by adding SrTiO3 nano-crystals as the initial phase of reaction. The lead-free piezoelectric ceramics were synthesized by the seed-induced method. The SrTiO3 nano-crystals used as seeds were prepared by molten salt technique. The seed content was varied from 0 to 10.0 mol%. The investigation reports microstructure and electrical properties of ceramics. The XRD showed a mixed tetragonal and orthorhombic phase structure. Tc decreasing with increased SrTiO3nano-crystal concentration.


2012 ◽  
Vol 512-515 ◽  
pp. 1198-1202
Author(s):  
Jia Mao Li ◽  
Tai Qiu

Microstructures and microwave dielectric properties of Ca(Sm0.5Nb0.5)O3 ceramics, prepared by a conventional solid-state reaction method, were systematically investigated by varying calcining temperature, sintering temperature and cooling rate. The XRD result showed that a single Ca(Sm0.5Nb0.5)O3 phase could be synthesized at a calcining temperature of 1200 °C. Optimized combination of microwave dielectric properties of εr = 22.36, Q×f = 18030 GHz and τf = -31.2 ppm/°C was obtained for furnace-cooled Ca(Sm0.5Nb0.5)O3 ceramics sintered at 1550 °C for 4 h. However, some microcracks were found from the microstructures of the furnace-cooled specimens. Further, the Q×f value could be increased by controlling the cooling rate during the sintering process due to the disappearance of microcracks in the final material. With a cooling rate of 2 °C/min, Ca(Sm0.5Nb0.5)O3ceramics exhibited an enhanced Q×f value of 37130 GHz.


2007 ◽  
Vol 280-283 ◽  
pp. 219-222
Author(s):  
Hua Jun Sun ◽  
Wen Chen ◽  
Qing Xu ◽  
Jing Zhou ◽  
Xiao Fang Liu

Using Zr(NO3)4.5H2O as Zr source, PZT powder with a single-phase perovskite structure was synthesized by a sol-autocombustion method at a calcining temperature of 700°C. Compared with a solid-state reaction method, the calcining temperature of PZT can be lowered by 200°C when using the sol-autocombustion method. PMZN ceramic was prepared at a sintering temperature of 1050°C with the resulting PZT powder as a base, which can lower the sintering temperature by 150°C. The microstructure of the PMZN ceramic was investigated by XRD and SEM, and the dielectric and piezoelectric properties were measured. The results showed that the PMZN piezoelectric ceramic has a tetragonal perovskite structure, showing the main electrical properties as follows: Kp = 0.54, Qm = 1073, tgd £ 0.001, e33 T/ e0 = 1236, d33 = 454pC/N, and fs =136.1KHz.


2018 ◽  
Vol 70 (3) ◽  
pp. 560-567 ◽  
Author(s):  
Jian Feng Li ◽  
Qin Shi ◽  
HeJun Zhu ◽  
ChenYu Huang ◽  
Shuai Zhang ◽  
...  

Purpose This paper aims to clarify the size and morphology of transition metal dichalcogenides has an impact on lubrication performance of Cu-based composites. This study is intended to show that Cu-based electrical contact materials containing Nb0.91Ti0.09Se2 have better electrical and tribological properties than those containing NbSe2. The tribological properties of Cu-based with different Ti-dopped NbSe2 content were also discussed. Design/methodology/approach The NbSe2 and Nb0.91Ti0.09Se2 particles were fabricated by thermal solid state reaction method. The powder metallurgy technique was used to fabricate composites with varying Nb0.91Ti0.09Se2 mass fraction. The phase composition of Cu-based composites was identified by X-ray diffraction, and the morphology of NbSe2/Nb0.91Ti0.09Se2 and the worn surface of composites were characterized by scanning electron microscopy and transmission electron microscopy. In addition, the tribological properties of composites were appraised using a ball-on-disk multi-functional tribometer. The data of friction coefficient and resistivity were analyzed and the corresponding conclusion was drawn. Findings In comparison with the pure copper, Cu-based composites containing Nb0.91Ti0.09Se2/NbSe2 had a lower friction coefficient, illustrating the Nb0.91Ti0.09Se2 with nano-size particles prepared in this work is a perfect choice for the fabrication of excellent electrical contact composites. Compared to composites with NbSe2, composites containing Nb0.91Ti0.09Se2 have better tribological and electrical properties. Research limitations/implications Because of the use of thermal solid state reaction method, the size of NbSe2 and Nb0.91Ti0.09Se2 is relatively large. Therefore, the fabrication of finer particles of Nb0.91Ti0.09Se2 is encouraged. Originality/value In this paper, the authors discuss the tribological and electrical properties of Cu-based composites, and the value of optimum obtained as Nb0.91Ti0.09Se2 content is 15 Wt.%.


Author(s):  
A. C. Iyasara ◽  
F. U. Idu ◽  
E. O. Nwabineli ◽  
T. C. Azubuike ◽  
C. V. Arinze

La2Ti2-xNbxO7 (x = 0.00, 0.05, 0.10, 0.15, 0.20, 0.25) powders were synthesised via solid state reaction method, followed by sintering at 1673 K in a reducing atmosphere of 5% H2/N2 gas. The crystal structure, microstructure and thermoelectric (TE) properties of the pure and Nb-doped La2Ti2O7 ceramics were investigated. All compositions were single phase with porous microstructures consistent with their low experimental densities. Thermoelectric results of Nb-doped compositions showed improved properties in comparison to pure La2Ti2O7, suggesting that cation doping has the potential to improve the thermoelectric properties. Generally, the TE results obtained are not suitable for thermoelectric applications. However, the high Seebeck coefficient (≥190 μV/K) and glass-like thermal conductivity ( ≤2.26 w / m.k )  values achieved have opened a new window for exploring the thermoelectric potentials of La2Ti2O7 and other related oxides.


RSC Advances ◽  
2018 ◽  
Vol 8 (28) ◽  
pp. 15613-15620 ◽  
Author(s):  
Xiaochun He ◽  
Ruiqing Chu ◽  
Zhijun Xu ◽  
Zhongran Yao ◽  
Jigong Hao

Lead-free ceramics, SrBi2Nb2O9–xBi2O3 (SBN–xBi), with different Bi contents of which the molar ratio, n(Sr) : n(Bi) : n(Nb), is 1 : 2(1 + x/2) : 2 (x = −0.05, 0.0, 0.05, 0.10), were prepared by conventional solid-state reaction method.


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