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Glass-ceramic materials were developed as a sealant in the solid oxide fuel cell (SOFC) in the temperature range of 800 -850 ℃. The glass materials were based on the glass and glass-ceramic in the BaO-CaO-Al2O3-SiO2-La2O3-B2O3 system. The thermal expansion coefficient (TEC) decreased with lower Ba^2+ content and higher Ca^2+ content, but the glass transition temperature and crystallization temperature increased greatly with an increase in Ca^2+ content and a decrease in Ba^2+ content, when the other components in the sealant were invariable. The TEC of the sealant with Ba^2+ content of 25.4% was 10.8 × 10^-6 K^- 1(temperature range from 25 to 850℃), and its softening temperature was 950 ℃. The TEC of the sealant accorded well with that of La0.9Sr0.1Ga0.5Mg0.2o3- 6(LSGM) with a mismatch of only 3%. The sealant had superior stability and compatibility with the LSGM electrolyte during the process of operation in SOFC. The weight loss of the sealant with Ba^2+ content of 25.4% was approfimately zero after heat-treated at 800℃ for 500 h in H2 and O2 atmosphere, respectively. 相似文献
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La1-xSrxGa1-yMgyO3-δ (LSGM) electrolyte, La1-xSrxCr1-yMnyO3-δ (LSCM) anode and La1-xSrxFe1-yMnyO3-δ (LSFM) cathode materials were all synthesized by glycine-nitrate process (GNP). The microstructure and characteristics of LSGM, LSCM and LSFM were tested via X-ray diffraction(XRD), scanning electron microcopy (SEM), A C impedance and four-probe direct current techniques. XRD shows that pure perovskite phase LSGM electrolyte and electrode (LSCM anode and LSFM cathode) materials were prepared after being sintered at 1400 ℃ for 20 h and at 1000 ℃ for 5 h, respectively. The max conductivities of LSGM (ionic conductivity), LSCM (total conductivity) and LSFM (total conductivity) materials are 0.02, 10, 16 S·cm-1 in the air below 850 ℃, respectively. The conductivity of LSCM becomes smaller when the atmosphere changes from air to pure hydrogen at the same temperature and it decreases with the temperature like metal. The porous and LSGM-based LSCM anode and LSFM cathode films were prepared by screen printing method, and the sintering temperatures for them were 1300 and 1250 ℃, respectively. LSGM and electrode (LSCM and LSFM) materials have good thermal and chemical compatibility. 相似文献
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Solidoxidefuelcells (SOFCs)haveseveraldis tinctadvantages ,e .g .,highenergyconversioneffi ciency ,wideadaptabilitytofuels ,theusageofnon preciousmaterials ,noliquids ,nocorrosions ,modularconstructionandmuchlowerproductionofNOx,SOxandnoise .Therefore ,theyreceiveincreasingatten tion[1,2 ] .AtypicalSOFCwhichutilizesyttria stabi lizedzirconia (YSZ)astheelectrolyterequireshighoperationtemperaturesuchas 10 0 0℃togainhighe noughionicconductivity .Loweringtheoperationtem peratureto 80 0℃wou… 相似文献
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Study on Preparation and Electrical Properties of Ba1.03 Ce0.2O3-α Solid Electrolyte 总被引:1,自引:0,他引:1
Ba1.03Ce0.8Eu0.2O3-α solid electrolyte with nonstoichiometric composition was prepared by high temperature solid-state reaction. Phase composition,surface and fracture morphologies of the specimen were characterized by using XRD and SEM,respectively. Ionic conduction was researched by gas concentration cell,the performance of hydrogen-air fuel cell was measured in the temperature range of 600~1000 ℃,and compared them with those of BaCe0.8Eu0.2O3-α and Ba0.98Ce0.8Eu0.2O3-α. The results indicate that Ba1.03Ce0.8Eu0.2O3-α is a single-phase perovskite-type orthorhombic system. It is a pure proton conductor in the temperature range of 600~1000 ℃ in hydrogen atmosphere,and its proton conduction is superior to that of BaCe0.8Eu0.2O3-α and Ba0.98Ce0.8Eu0.2O3-α. It is a mixed conductor of oxide ion and electron hole in oxygen atmosphere. At 1000 ℃,the performance of the fuel cell in which Ba1.03Ce0.8Eu0.2O3-α as electrolyte is higher than that of BaCe0.8Eu0.2O3-α or Ba0.98Ce0.8Eu0.2O3-α. 相似文献
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Fabrication and Characterization of Glass-Ceramics Doped with Rare Earth Oxide and Heavy Metal Oxide
Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO2) and heavy metal oxide (M2O3) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results show that the additives both heavy metal oxide and rare earth oxide promote the sintering and lower the phase temperature from μ- to α-cordierite as well as affect the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples is as low as 900 ℃. The materials have a low dielectric constant (≈5), a low thermal expansion coefficient ((2.80~3.52)×10-6 ℃-1) and a low dissipation factor (≤0.2%) and can be co-fired with high conductivity metals such as Au, Cu, Ag/Pd paste at low temperature (below 950 ℃), which makes it to be a promising material for low-temperature co-fired ceramic substrates. 相似文献
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高纯单—稀土是新型稀土功能材料的主要原料,为此国家安排了“八五”重点科技攻关项目。本文采用了溶剂萃取、萃淋树脂色层、离子交换、氧化和还原等多种分离提取技术将Sc2O3、Y2O3、La2O3、CeO2、Pr6O11、Nd2O3、Sm2O3、Eu2O3、Gd2O3、Tb4O7、Dy2O3、Ho2O3、Er2O3、Tm2O3、Yb2O3、Lu2O3等十六种单—稀土氧化物分别提纯到5N以上(稀土纯度)。其中大部分纯度大于6N,收率>85%;工艺合理、技术新颖、质量稳定、处理量大、成本低廉。专家评审认为产品填补国内空白,达到国际先进水平。 相似文献
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Development of Doped Lanthanum Gallate Solid Electrolytes 总被引:1,自引:0,他引:1
Development of the doped lanthanum gallate solid electrolytes in the recent years was reviewed. The structure and oxygen ion transference mechanism were discussed. Effects of alkali earths, transition metals, and impurities on electrical conductivity of the doped lanthanum gallates were also discussed. The applications of doped lanthanum gallate were described. The current problems and corresponding strategies were explored. 相似文献
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Ce0.6Zr0.3RE0.1O2(RE=Y, La, Pr, Tb)solid solutions were prepared by co-precipitation technique and characterized by a series of methods. XRD and FT-Raman results show that Ce0.6Zr0.3RE0.1O2 has cubic fluorite structure. The different dopant ion radii bring different effect on the cell parameter of Ce0.6Zr0.3RE0.1O2. The X-ray photoelectron spectroscopy (XPS) results show that the binding energy of Ce3d, Zr3d and O1s for Ce0.6Zr0.3RE0.1O2 rises compared with that for Ce0.6Zr0.4O2, indicating that dopant elements change chemistry environment of solid solutions which is available to improve redox performance. Compared with Pd/Ce0.6Zr0.4O2, doping Y and La does not change air/fuel (A/F) characteristic of TWCs, but doping Pr and Tb widens A/F operating window and makes HC, CO and NO have higher conversion. The light-off temperature of Pd/Ce0.6Zr0.3La0.1O2 is corresponding to that of Pd/Ce0.6Zr0.4O2. However, the light-off temperatures of Pd/Ce0.6Zr0.3M0.1O2 (M=Y, Pr, Tb) are lower than that of Pd/Ce0.6Zr0.4O2, which keep much lower after high temperature treatments. Among Pd/Ce0.6Zr0.3RE0.1O2, Pd/Ce0.6Zr0.3Tb0.1O2 represents wider A/F operating window, higher conversion, lower light-off temperature and better high-temperature resistance. 相似文献
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DeterminationofTraceImpuritiesofRareEarthElementsinHighPurityYttriumOxidebyICPMS¥LiuJinglei;TongYingdong;ZhangXinquan(Centreo... 相似文献
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Diesel oxide catalysts and soot combustion catalysts were reported in this paper.The former was manufactured in mass last year, and enhanced performance is under development now.The later is screened out and further research is under way.The best soot combustion catalyst could ignite soot combustion even at 350 ℃, which is within the range of temperatures reached in diesel exhaust, and shows the catalytic combustion velocity nearly one time faster compared with non-catalytic combustion of soot, which is of benefit to rapid regeneration of diesel particulate filter, thus it might be an excellent practicable catalyst. 相似文献
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XPS Studies on Rare Earth Oxide LSCO/YSZ Electrodes 总被引:6,自引:0,他引:6
The X-ray diffraction spectra and X-my photoelectron spectroscopy were measured for Sr-doped Lal-xSrx CoO3 materials with perovskite structure prepared by the solid-state reaction method. The influence of heat-treatment tempera-ture on the average crystal size of Lal-xSrx CoO3 was studied. The surface chemical states of Lal-xSrxCoO3 cathodes with different Sr-doped content were discussed. The experimental results show that average crystal size of Lal-xSrxCoO3 under the condition of heat-treatment in the range of 900- 1200℃ is larger than that at other temperatures, which is of benefit to forming porous electrodes. When La is replaced by Sr gradually, the oxygen vacancy concentration increases. It is of benefit to enhancing the transport property of oxygen ion. 相似文献
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Huang Xiaowei Li Hongwei Xue Xiangxin Zhang Guocheng 《中国稀土学报(英文版)》2006,24(2):154-154
Characteristic and hydrometallurgy processes for Baotou mixed-type rare earth concentrate, bastnasite, and ionic adsorption deposit in China were reviewed. The R & D circumstance and new progresses in extraction and separation of RE element in China were introduced. Moreover, the development trend of RE hydrometallurgy was predicted. The direction and emphasised fields of research and development are also brought forward as: to R & D high efficient green progresses in hydrometallurgy and separation of RE ore, resolve the waste pollution problem of water, slagand gas, reduce the chemical material consumption and improve comprehensive efficiency of resources; to R & D preparation technology for RE compounds with ultra high-purity and special physical property for extending application fields of RE. 相似文献
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This work relates to a new type of ceramic with far infrared rays emitting function for improving fuel efficiency, and more particularly for enhancing the combustion efficiency. According to the far infrared rays absorption properties of fuel, some rare earth is added to the ceramic to radiate some far infrared rays with special wavelength. And the effect of rare earth on the fuel activation of the ceramic was investigated.. It is shown that the rare earth cooperates with the ceramic improving the far infrared rays radiation ability. The radiance can reach 90%. With the device of the invention, the double bonds between carbon atoms in the hydrocarbon fuel are broken down to form smaller hydrocarbon molecules lowering the volatilization point thereby enhancing the combustion efficiency. According to the test results,the fuel consumption rate is improved by 4.4%. At the same time, deleterious gas output is reduced obviously to achieve energy conservation and prevent environmental pollution. 相似文献
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Effects of Rare Earth Oxide on Microstructure of Zinc Varistors 总被引:1,自引:1,他引:0
Zhu Jianfeng Gao Jiqiang Wang Fen Luo Hongjie 《中国稀土学报(英文版)》2006,24(5):542-542
The influence of Pr6O11 on the microstructure of ZnO varistors was researched. The results of experiment indicate that addition of Pr6O11 leads to the change of the formation process of the spinel phase. A lot of pyrochlore phases ( Bi3Zn2Sb3O14 ) produce at about 700℃, and decompose to fine spinel phase (Zn7Sb2O12) when the temperature reaches to 900℃.This type of spinel phase makes ZnO crystal size minor. Also, the phase contained the Pr and different Pr oxides, which makes the whole material crystal size more uniform and compact. The fine structure improves the threshold voltage by about 60%, and modifies nonlinear coefficient of the ZnO material. 相似文献
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Rare earth-based AB5-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the metahydride hydrogen-diffusion electrodes could be charged by hydrogen gas and electrochemically discharged at the same time to retain a stable oxidation potential for a long period. The catalytic activities and stability are almost comparable with a Pt catalyst on the active carbon. Further improvement of performances is expected via reduction of catalyst size into nanometers. 相似文献
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屠海令 《中国稀土学报(英文版)》2004,22(5):571-575
The development of rare earths (RE) applications to semiconductor materials and devices is reviewed. The recent advances in RE doped silicon light emitting diodes (LED) and display materials are described. The various technologies of incorporating RE into semiconductor materials and devices are presented. The RE high dielectric materials, RE silicides and the phase transition of RE materials are also discussed. Finally, the paper describes the prospects of the RE application to semiconductor industry . 相似文献