EFFECT OF SINTERING TEMPERATURE ON THE MICROSTRUCTURE AND THERMOELECTRIC PROPERTIES OF Ca2.7Bi0.3Co4O9

2009 ◽  
Vol 23 (18) ◽  
pp. 3777-3787 ◽  
Author(s):  
HAOSHAN HAO ◽  
SHAOFENG LI ◽  
LIMIN ZHAO ◽  
XING HU
Keyword(s):  
Solid State ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Cooling Stage ◽  
Oriented Structure

Ca 2.7 Bi 0.3 Co 4 O 9 samples have been sintered in temperature range of 1183–1243 K by conventional solid-state reaction method. XRD and SEM investigations show that c-axis-oriented structure could be formed in these samples and Lotgering factors increase with the increase of sintering temperature when it is below 1223 K, from 52% for the sample sintered at 1183 K to 86% for the sample sintered at 1223 K. Due to decomposition of Ca 2.7 Bi 0.3 Co 4 O 9, however, the c-axis-oriented structure was destroyed in the sample sintered at 1243 K although Ca 2.7 Bi 0.3 Co 4 O 9 phase could be recovered at the cooling stage. The size of grains in all samples increases with the increase of sintering temperature, but the relative densities are almost kept unchanged for the samples sintered at the temperature higher than 1183 K. Due to the highly textured structure, the transport properties of the sample sintered at 1223 K are anisotropic and its ZT values in the ab plane are obviously larger than those along the c-axis.

The Morphologies and Photoluminescence of Ce3+-Doped 0.5La2O3-2SrO-0.5Al2O3 Phosphors with SrF2

2016 ◽  
Vol 680 ◽  
pp. 228-232
Author(s):  
Xi Guang Gu ◽  
Ren Li Fu ◽  
Ye Tang ◽  
Fang Yang
Keyword(s):  
Solid State ◽  
White Light ◽  
Solid State Reaction ◽  
Emission Intensity ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Light Emitting ◽  
Reaction Method ◽  
Reducing Atmosphere ◽  
White Light Emitting Diodes

Ce3+-doped 0.5La2O3-2SrO-0.5Al2O3 (LSA:Ce) phosphors had been successfully synthesized using a conventional solid-state reaction method under reducing atmosphere (H2/N2 =1/5). The phase, morphologies and luminescence properties of the LSA:Ce phosphors were investigated. The emission intensity of LSA:Ce phosphors was improved by the addition of SrF2 as flux, and red shift of PL spectra peak was observed in this phosphors. Research results shown that the LSA:Ce phosphors have the potential to meet the development of white light-emitting diodes.

Influence of R3+ ion sizes on the thermoelectric properties of RBaCo4O7+δ ceramics

2015 ◽  
Vol 29 (26) ◽  
pp. 1550154 ◽  
Author(s):  
F. Gao ◽  
Q. L. He ◽  
F. Wu ◽  
D. L. Yang ◽  
X. Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Oxygen Adsorption ◽  
Reaction Method ◽  
Transition Phenomenon ◽  
Seebeck Coefficients

The influence of [Formula: see text] ion sizes on the electrical resistivity, Seebeck coefficients, thermal conductivity and [Formula: see text] values of [Formula: see text] prepared by the solid-state reaction method was investigated from 373 K to 973 K. The electrical resistivity decreases with decreasing [Formula: see text] ion sizes. Both the electrical resistivity and the Seebeck coefficients have a transition at about 630 K. Especially, the transition phenomenon disappears gradually with decreasing [Formula: see text] ion sizes, and is attributed to the oxygen adsorption of [Formula: see text]. The [Formula: see text] values increase with rising temperature or decreasing [Formula: see text] ion sizes. The [Formula: see text] with the smallest [Formula: see text] size has the maximum [Formula: see text] value that reaches 0.1 at 973 K.

A high temperature stable piezoelectric strain of KNN-based ceramics

2018 ◽  
Vol 6 (41) ◽  
pp. 19967-19973 ◽  
Author(s):  
Zhenyong Cen ◽  
Yu Huan ◽  
Wei Feng ◽  
Yan Yu ◽  
Peiyao Zhao ◽  
...  
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Solid State Reaction ◽  
Piezoelectric Ceramics ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Piezoelectric Strain

Lead-free (1 − x)(0.96K0.46Na0.54Nb0.98Ta0.02O3–0.04Bi0.5(Na0.82K0.18)0.5ZrO3)–xCaZrO3 ((1 − x)(0.96KNNT–0.04BNKZ)–xCZ) piezoelectric ceramics were prepared by the conventional solid-state reaction method.

scholarly journals Effect of Bi2O3 content on the microstructure and electrical properties of SrBi2Nb2O9 piezoelectric ceramics

RSC Advances ◽  
2018 ◽  
Vol 8 (28) ◽  
pp. 15613-15620 ◽  
Author(s):  
Xiaochun He ◽  
Ruiqing Chu ◽  
Zhijun Xu ◽  
Zhongran Yao ◽  
Jigong Hao
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Molar Ratio ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Lead Free Ceramics ◽  
Bi2o3 Content

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.

Photocatalytic properties of MIn(WO4)2 (M = Li, Na, and K)

2007 ◽  
Vol 22 (4) ◽  
pp. 958-964 ◽  
Author(s):  
Zhaosheng Li ◽  
Jinhua Ye ◽  
Zhigang Zou
Keyword(s):  
Solid State ◽  
Aqueous Solutions ◽  
High Activity ◽  
Solid State Reaction ◽  
Pure Water ◽  
Solid State Reaction Method ◽  
Photocatalytic Properties ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Conduction Bands

MIn(WO4)2 (M = Li, Na, and K) with InO6 and WO6 octahedra were synthesized via a conventional solid-state reaction method. The photophysical and photocatalytic properties were studied. Compared with WO3, which is unable to evolve H2 from an aqueous CH3OH solution under illumination, the three materials can evolve H2 and O2 from aqueous solutions with CH3OH and AgNO3 sacrificial reagents, respectively. The activity order of photocatalytic H2 evolution is NaIn(WO4)2 > LiIn(WO4)2 > KIn(WO4)2 under irradiation (λ > 200 nm). Under irradiation (λ > 300 nm), however, LiIn(WO4)2 has a high activity for photocatalytic H2 evolution over NaIn(WO4)2. It is also noteworthy that LiIn(WO4)2 and NaIn(WO4)2 exhibit the ability to split pure water. The results suggest that the bottoms of the conduction bands in these photocatalysts are raised to meet the potential requirements of photocatalytic H2 evolution.

Dielectric Properties of Ba(Mg0.2/3Zn0.8/3Nb2/3)O3 and Ba1-xSrx(Mg0.2/3Zn0.8/3Nb2/3)O3 Microwave Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 272-274
Author(s):  
S.S. Cheng ◽  
J. Luo ◽  
Zhao Xian Xiong
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Resonant Frequency ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Zero Temperature ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Zn Ions

Microwave ceramics of Ba(Mg0.2/3Zn0.8/3Nb2/3)O3 and Ba1-xSrx(Mg0.2/3Zn0.8/3Nb2/3)O3 were synthesized with conventional solid-state reaction method. Dielectric properties of the samples were studied as functions of compositions and sintering temperatures. Experimental results show that a higher Q×f value is reached by substituting Zn ions with Mg ions and a near-zero temperature coefficient of resonant frequency is obtained by replacing Ba ions with Sr ions.

Effects of Mg2SiO4 Addition on the Microstructure and Dielectric Properties of MgTiO3-CaTiO3 Ceramics

2013 ◽  
Vol 675 ◽  
pp. 200-204
Author(s):  
Fei Shi ◽  
Peng Cheng Du ◽  
Jing Xiao Liu ◽  
Ji Wei Wu ◽  
De Qing Chen ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Dielectric Loss ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Composite Ceramics ◽  
Reaction Method ◽  
Dielectric Ceramics

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.

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