scholarly journals The low infrared emissivity of Ce1-xYxO2-x/2 samples at high-temperature contributed by enhanced conductivity

2018 ◽  
Vol 238 ◽  
pp. 03002
Author(s):  
Honghan Bu ◽  
Chuyang Liu ◽  
Guoyue Xu ◽  
Yong Jiang ◽  
Tengchao Guo ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solid State Reaction Method ◽  
Potential Candidate ◽  
Aircraft Engines ◽  
Infrared Emissivity ◽  
Doping Amount ◽  
Reaction Method ◽  
Phase Structures ◽  
Increasing Temperature ◽  
Enhanced Conductivity

The Ce1-xYxO2-x/2 samples were synthesized with different doping amount by solid state reaction method. Phase structures of the samples were analyzed and characterized by XRD. The effects of different doping amount on infrared emissivity properties at 3-5µm wavebands were investigated systematically. It is found that the powder with doping molality of x=0.2 exhibits the lowest infrared emissivity value ca. 0.21 when the test temperature is 600 °C. The mechanism for the low infrared emissivity is explored thoroughly. The reduction of infrared emissivity with increasing temperature is ascribed to the enhancement of electrical conductivity. Our results suggest that Ce1-xYxO2-x/2 powder with x=0.2 is a potential candidate for stealth material of aircraft engines.

TEXTURED STRUCTURE AND ANISOTROPIC THERMOELECTRIC PROPERTIES OF Ca2.7Bi0.3Co4O9 OXIDE PREPARED BY CONVENTIONAL SOLID-STATE REACTION

2009 ◽  
Vol 23 (01) ◽  
pp. 87-95 ◽  
Author(s):  
HAOSHAN HAO ◽  
QINGLIN HE ◽  
CHANGQING CHEN ◽  
HONGWEI SUN ◽  
XING HU
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Bi Doping

Ca 3-x Bi x Co 4 O 9(x = 0.0, 0.3) samples have been prepared at 1223 K by conventional solid-state reaction method. XRD and SEM investigations reveal that c-axis-oriented structure could be formed in Ca 2.7 Bi 0.3 Co 4 O 9 samples, whereas grains in Ca 3 Co 4 O 9 samples distribute randomly. Moreover, Bi doping increases the grain size and relative density of Ca 2.7 Bi 0.3 Co 4 O 9. The electrical conductivity along the ab plane for Ca 2.7 Bi 0.3 Co 4 O 9 is about four times as large as that along the c-axis, but the Seebeck coefficient is almost isotropic, which leads to a remarkable rise of the power factor in ab plane for Ca 2.7 Bi 0.3 Co 4 O 9 compared with untextured Ca 3 Co 4 O 9. The textured structure in Ca 2.7 Bi 0.3 Co 4 O 9 sample should be attributed to the effect of Bi doping.

Study on the Property of Ba0.85Ca0.15Ti0.9Zr0.1O3 Lead-Free Piezoelectric Ceramics Doped with Li2CO3

2012 ◽  
Vol 549 ◽  
pp. 651-654 ◽  
Author(s):  
Zhi Wen Zhu ◽  
Xin You Huang ◽  
Hai Tang Hua ◽  
Yan Li
Keyword(s):  
Grain Size ◽  
Piezoelectric Properties ◽  
Piezoelectric Ceramics ◽  
Solid State Reaction Method ◽  
Lead Free ◽  
Doping Amount ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Mechanical Coupling ◽  
Planar Electron

Ba0.85Ca0.15Ti0.9Zr0.1O3-xLi2CO3 lead-free piezoelectric ceramics (abbreviated as BCZT-xLi) were prepared by conventional solid state reaction method. The microstructure, piezoelectric properties and dielectric properties were studied for BCZT-xLi samples doped with different Li2CO3 content(x= 0, 0.05, 0.1 0.2 0.3, 0.4wt. %). The results show that the piezoelectric constant(d33), planar electron mechanical coupling coefficient(kp) and thickness electron mechanical(kt) of BCZ-T-xLi ceramics increase firstly and decreases subsequently with increasing of Li+ doping amount, the dielectric loss(tanδ) of BCZT-xLi ceramics decreases firstly and then increases at the same time while Li+ doping amount increases. But the r-elative permittivity (εr) of BCZT-xLi ceramics increases all the time. With the in-creasing of the amount of Li2CO3 doped the grain size of BCZT-Li ceramic first increases and then decreases. The BCZT-xLi ceramics display the optimum properties (d33=83, tanδ=0.035, εr=2020, kp=0.41, kt=0.046) while Li2CO3 doped amount is 0.20wt. %.

Electrical Conductivity and Characterization of CeO2 Doped 8YSZ Electrolyte with 2%wt CuO Doping

2012 ◽  
Vol 512-515 ◽  
pp. 1564-1568
Author(s):  
Jia Song Zhang ◽  
Ye Fan Wu ◽  
Ling Hong Luo ◽  
Guo Yang Shen ◽  
Hui Su
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Electrical Properties ◽  
Solid State Reaction Method ◽  
Testing Temperature ◽  
Reaction Method ◽  
Electrolyte Conductivity ◽  
Densification Temperature ◽  
Powder Characteristics

Nano-sized electrolyte of CeO2 doped 8YSZ with 2%mol CuO (YSZDC)powders were synthesized by solid state reaction method. Powder characteristics and electrical properties was characterized by XRD,SEM and Electrochemical workstation.The results demonstrate that the as-synthesized Y0.08Zr0.72Ce0.2O1.6 (YSZDC) and Y0.08Zr0.72Ce0.18Cu 0.02O1.6-δ(YSZDC-Cu0.02) possessed similar powder characteristics, including cubic fluorite crystalline structure.About 150 °C reduction in densification temperature of Y0.08Zr0.72Ce0.18Cu0.02O1.6-δ was obtained when compared with Y0.08Zr0.72Ce0.2O1.6.The YSZDC-Cu0.02 pellets sintered at 1300 °C and the YSZDC sintered at 1450 °C exhibited relative densities of 95.66% and 94.73%,respectively.Electrolyte matrixs were prepared for electrolyte-supported SOFCs(ES-SOFC) , the suspension of NiO-YSZ anode was sprayed on the electrolyte, after co-sintering at 1300°C,electrolyte matrixs and anode were well adhered each othert, without connecting pores and cracks observed. Moerover, well electricity performance were showed by YSZDC and YSZDC-Cu0.02 at a testing temperature of 750°C,And the electrolyte conductivity didn’t decrease obviously with dopping CuO.

Infrared Emittance and Electrical Properties of Ce4+ Doped Sm0.5Sr0.5CoO3 Ceramics

2019 ◽  
Vol 294 ◽  
pp. 45-50
Author(s):  
Le Chen ◽  
Wang Zhan ◽  
Hui Min Sun ◽  
Zhao Zhan Gu
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Spectral Reflectance ◽  
Initial Phase ◽  
Solid State Reaction Method ◽  
Thermal Conversion ◽  
Reaction Method ◽  
Radiation Properties ◽  
Opening Up ◽  
Conductivity Behavior

A series of Sm0.5Sr0.5CoO3-CeO2 ceramics formed by solid state-reaction method have been systematically investigated. The effects of doping the Sm site of Sm0.5Sr0.5CoO3 with Ce4+ on the structural, spectral reflectance, and thermal radiation properties were also explored. The modification of the initial phase takes place can be ascribed to the dissolution of Ce from initial CeO2 into the perovskite structure. The conductivity behavior depends critically on the Ce doping level, as was demonstrated that the recombination of holes (from Sm0.5Sr0.5CoO3) and electrons (from ceria ion) could decrease electrical conductivity. Sm0.5Sr0.5CoO3-CeO2 ceramics showed continuously adjustable conductivity and infrared emittance, opening up possible applications in solar thermal conversion or thermosensitive conductivity.

Thermoelectric Properties of Cu-Substituted Bi2Ca2Co2Oy Misfit Oxides

2011 ◽  
Vol 284-286 ◽  
pp. 2263-2267 ◽  
Author(s):  
Hao Shan Hao ◽  
Qing Lin He ◽  
Li Min Zhao
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Seebeck Coefficients ◽  
Cu Substitution ◽  
Performance System

Co2-xCuxOy (x=0.0, 0.2, 0.4) Samples were prepared by solid-state reaction method and the effect of Cu substitution on the thermoelectric properties was investigated. The presence of Cu element improved the grain size and electrical conductivity, but Seebeck coefficients were reduced by Cu substitution. It was found Cu substitution is an effective way to improve the thermoelectric performance system at high temperature.

scholarly journals Phase Stability of The Mixed-Conducting Sr-Fe-Co-O System

1997 ◽  
Vol 496 ◽  
Author(s):  
B. Ma ◽  
U. Balachandran ◽  
J. P. Hodges ◽  
J. D. Jorgensen ◽  
D. J. Miller ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Elevated Temperatures ◽  
Cobalt Content ◽  
Ceramic Membranes ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Ceramic Oxides ◽  
Partial Pressures ◽  
Dense Ceramic ◽  
Increasing Temperature

ABSTRACTMixed-conducting ceramic oxides have potential uses in high-temperature electrochemical applications such as solid oxide fuel cells, batteries, sensors, and oxygen-permeable membranes. The Sr-Fe-Co-O system combines high electronic/ionic conductivity with appreciable oxygen permeability at elevated temperatures. Dense ceramic membranes made of this material can be used to separate high-purity oxygen from air without the need for external electrical circuitry, or to partially oxidize methane to produce syngas. Samples of Sr2Fe3-xCoxOy (with x = 0,0.6,1.0, and 1.4) were prepared by solid-state reaction method in atmospheres with various oxygen partial pressures (pO2) and were characterized by X-ray diffraction, scanning electron microscopy, and electrical conductivity testing. Phase components of the sample are dependent on cobalt concentration and pO2. Electrical conductivity increases with increasing temperature and cobalt content in the material.

Study of thermoelectric properties of Ca-doped LaCoO3

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540026 ◽  
Author(s):  
Kei-Ichiro Murai ◽  
Ken Nagai ◽  
Masaru Takahashi ◽  
Shosuke Takakusa ◽  
Toshihiro Moriga
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Ca Substitution

The samples of La 1-x Ca x CoO 3 (x = 0, 0.05, 0.10, 0.15) were synthesized by solid state reaction method for studying thermoelectric properties. The properties of electrical conductivity and Seebeck coefficient were measured in the temperature ranging from room temperature to 573 K. The results of electrical conductivity was increasing Ca substitution. The highest value of electrical conductivity is 1574 S/cm. It is concluded that Ca 2+ doping in LaCoO 3 has the effect to inhibit Seebeck coefficient from decreasing.

Thermoelectric Characteristics of Pb- and La-Doped Bi2Ba2Co2OY Ceramics

2011 ◽  
Vol 228-229 ◽  
pp. 804-808 ◽  
Author(s):  
Hao Shan Hao ◽  
Hai Peng Yu ◽  
Li Min Zhao
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Co Doping ◽  
Seebeck Coefficients ◽  
Element Doping ◽  
Pb Doping ◽  
La Doped

Pb- and La-doped (Bi,Pb)2(Ba,La)2Co2Oy ceramics were prepared by solid-state reaction method and the effect of element doping on the thermoelectric characteristics was investigated. Pb and La doping increased the electrical conductivity and transformed the conduction from a metal-like behavior to a semiconducting one. Different from the undoped samples, the values of Seebeck coefficients decreased with the increase of the temperature in the Pb- and La-doped samples. Pb doping in Bi2Ba2Co2Oy system improved the thermoelectric characteristics at high temperature and Pb/La co-doping improved thermoelectric characteristics at low temperature.

Na-Site Doping of NaCo2O4 Thermoelectric Materials

2007 ◽  
Vol 336-338 ◽  
pp. 802-804 ◽  
Author(s):  
Ying Li ◽  
Li Hua Zhang ◽  
Shu Lan Wang ◽  
Gui Ying Xu ◽  
Mao Fa Jiang
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Maximum Power ◽  
Reaction Method

The K, Ca, Sr and Ce doped and non-doped γ-NaxCo2O4 samples were prepared by the solid-state reaction method. Results show that the Na-site doping might lead to an increase in the Seebeck coefficient and a decrease in the electrical conductivity of the samples. The maximum power factors of the K, Ca and Sr doped samples are respectively 2.04, 1.93 and 1.9 W·m-1·K-2, corresponding to an increase by 58%, 50% and 47% compared with that of the non-doped samples. Thus, the Na-site doping can improve the thermoelectric properties of γ-NaxCo2O4 oxides.

A-SITE DEFICIENCY AND STRUCTURAL AND ELECTRICAL CHARACTERISTICS OF (Sr1-xREx)1-yTiO3 PEROVSKITES (RE=La, Nd and Sm)

2012 ◽  
Vol 06 ◽  
pp. 85-90 ◽  
Author(s):  
TOSHIHIRO MORIGA ◽  
SHINTARO YABUI ◽  
YUTA HIGASHI ◽  
KEI-ICHIRO MURAI ◽  
ZHEN-WEI WANG ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Solid State Reaction Method ◽  
Impurity Phase ◽  
Electrical Characteristics ◽  
Conductivity Measurements ◽  
Metallic Behavior ◽  
Reaction Method ◽  
Absolute Value ◽  
A Site

The A-site deficient ( Sr 1- x RE x )1- y TiO 3 perovskites ( RE = La , Nd and Sm , 0≤ x ≤0.5, y =0, 0.05 and 0.10) were studied using samples prepared by solid-state reaction method. The substitution of Sr by the smaller RE seemed to result in the increased x region of TiO 2 appearance as an impurity phase against the larger y compositions. A slope of the tied line of the lattice parameters a as a function of x was steepened with an increase of y . Electrical conductivity measurements of ( Sr 0.9 RE 0.1)1- y TiO 3 revealed that the samples without cationic deficiency in the A-site were semiconducting whereas the A-site deficient samples showed basically metallic behavior. The absolute value of observed conductivities for all the measured samples were also reduced in the order of the size of RE .

Sign in / Sign up

Export Citation Format

Share Document