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Bonding of Silicon Nitride Ceramic Composite with RE_2O_3Al_2O_3SiO_2 Glass Solders

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Journal of Rare Earths 1999年第3期17卷 194-199页

作者：周飞李志章罗启富 Department of Materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212013 China Department of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

Liquid bonding of Si 3N 4 ceramic composite was carried out with RE 2O 3 Al 2O 3 SiO 2 glass solders. The effect of bonding conditions and interfacial reaction on the joint strength was studied. The joint strength under different bonding conditions was measured by four point bending tests. The interfacial microstructures were observed and analyzed by SEM, EPMA and XRD. It is shown that the liquid glass solders react with Si 3N 4 at interface, forming the Si 3N 4/Si 2N 2O/Y(La) sialon glass/Y(La) sialon glass gradient interface. With the increase of bonding temperature and holding time, the joint strength first increased reaching a peak, and then decreased. According to microanalyses, LaYO 3 precipitated from joint glass improves joint strength at room and high temperature.

关键词： Rare earths Si 3N 4 ceramic composite lanthana Yttria Bonding

Influence of [La(EDTA)]^- on pore structure of activated alumina carrier at high-temperature

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Journal of Rare Earths 2010年第S1期28卷 326-328页

作者：刘晓军徐炳辉吴玉胜张林楠 Shenyang University of Technology School of Science

The activated alumina as a catalyst carrier were widely used in automotive exhaust catalysts under high temperature,such as,petroleum refining catalysts,hydrogenation and hydrodesulfurization catalyst carrier in China and abroad.γ-Al2O3 was the catalyst carrier that was the most widely used and the best carrier of improved specific surface area .However,the activation of the coating consisted of γ-Al2O3 were usually transformed into α-Al2O3 at 800 oC,causing increased density,reduced specific surface area,and the collapse result of pore *** the temperature reached 1200 oC,activation of coating detached from the carrier,the resistance of flowing gas increased,catalytic activity *** of La2O3 stabilized the γ-Al2O3 crystal structure,which would keep the activation stability of coating at a high temperature and inhibit activity *** activated alumina carrier treated with the solid-pore-expanding agent containing [La(EDTA)]-that synthesized using solid and solid-hybrid approach with the thermal stabilizer lanthana and EDTA at the high-temperature had a 10-30 μm large pore porous network-like structure,after alumina was calcined at 1200 oC for 1 *** specific surface area of four specimen were beyond 120 m2/g,while the sample specific surface area of x([La(EDTA )]-)=1% was up to 150.36 m2/g.

关键词： alumina lanthana specific surface area thermal stability pore-expanding agent rare earths

Synthesis of La^(3+) and Nd^(3+) co-doped yttria nanopowder for transparent ceramics by oxalate precipitation method

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Journal of Rare Earths 2010年第2期28卷 232-236页

作者：王能利张希艳邱关明孙海鹰刘全生米晓云王晓春 School of Materials Science and Engineering Changchun University of Science and Technology

Polycrystalline Nd3+ and La3+ co-doped yttria nanopowder Nd3+:Y1.90La0.10O3 for transparent ceramics was synthesized by co-precipitation method using oxalate acid as the precipitant and(NH4)2SO4 as the electrical stabilizer under ultrasonic *** calcined at different temperatures were characterized with thermal gravimetric-differential thermal analysis(TG/DTA),X-ray diffraction(XRD),transmitting electron microscopy(TEM),energy dispersive spectrometry(EDS) and spectral analysis ***...

关键词： yttria nanopowder lanthana oxalate co-precipitation transparent ceramics rare earths

Influence of La_2O_3 on preparation and performance of porous cordierite from rice husk

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Journal of Rare Earths 2010年第4期28卷 614-617页

作者：郭伟陆洪彬冯春霞 Department of Materials Engineering Yancheng Institute of Technology

A porous cordierite was synthesized at 1350 ℃ using rice husk as silica source and pore forming agent, and La2O3 as fluxing agent. The crystal phases of the cordierite were analyzed by X-ray diffraction (XRD) and their microstructures were observed by scanning electronic microscopy (SEM). The flexural strength, porosity and thermal expansion coefficient of the porous cordierite samples were inves- tigated in detail. Results showed that when 5 wt.% La2O3 was added, the flexural strength, porosity and thermal...

关键词： porous ceramic cordierite rice husk lanthana

A Novel Catalyst for Liquid Phase Hydrogenation of m-Dinitrobenzene to m-Phenylenediamine

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Chinese Chemical Letters 2005年第4期16卷 531-533页

作者： YingXinLIU ZuoJunWEI JiXiangCHEN JiYanZHANG XinXueLI XiongHuiWEI DepartmentofAppliedChemistry CollegeofChemistryandMolecularEngineeringPekingUniversityBeijing100871 DepartmentofEnvironmentalEngineering ColliegeofEnvironmentalSciencesPekingUniversityBeijing100871 DepartmentofCatalysisScienceandEngineering SchoolofChemicalEngineeringandTechnologyTianjinUniversityTianjin300072

A novel lanthana-promoted nickel catalyst supported on silica for the liquid phase hydrogenation of m-dinitrobenzene to m-phenylenediamine was prepared by an incipient wetness sequential impregnation method. It was found that Ni-La/SiO2 catalyst exhibited high activity and stability for m-dinitrobenzene hydrogenation. Over this catalyst, the conversion of m-dinitrobenzene and the yield of m-phenylenediamine were up to 97.1% and 93.5%, respectively, at 373 K and 2.6 MPa hydrogen pressure after reaction for 1 h.

关键词： Nickel catalyst lanthana hydrogenation m-phenylenediamine m-dinitrobenzene.

Partial hydrogenation of adiponitrile to 6-aminocapronitrile over Ni/α-Al_2O_3 catalyst promoted with K_2O and La_2O_3

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Chinese Chemical Letters 2007年第6期18卷 685-688页

作者： Lei Zhao, Cai Yun Wang, Ji Xiang Chen , Ji Yan Zhang Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China Department of Catalysis Science and Engineering School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

A novel K2O and La2O3 promoted nickel catalyst supported on a-Al2O3 was prepared by co-impregnation method, and it exhibited higher activity and 6-aminocapronitrile selectivity than Ni/a-Al2O3 during the hydrogenation of adiponitrile in the absence of ammonia, i.e., K2O and La2O3 improved the performance of the nickel-based catalyst.

关键词： Nickel catalyst Potassium oxide lanthana Partial hydrogenation Adiponitrile 6-Aminocapronitrile

Methane Decomposition over Ni/α-Al_2O_3 Promoted by La_2O_3 and CeO_2

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Journal of Natural Gas Chemistry 2003年第3期12卷 183-188页

作者： PengboJiang YongchenShang TiexinCheng YingliBi KeyingShi ShuquanWei GuolinXu KaijiZhen CollegeofChemistry JilinUniversityChangchun130023China DepartmentofChemistry HarbinNormalUniversityHarbin150080China

The decomposition of methane on Ni/α-Al_2O_3 modified by La_2O_3 and CeO_2with different contents has been investigated and the ralationship between methane decomposition andremoval of carbon by CO_2 over these catalyst has also been studied by pulse-chromatography. Thecatalysts were characterized by TPR and XRD. It was shown that Ni/α-Al_2O_3 could be promoted byadding La_2O_3, and the carbon species produced over this catalyst was activated and eliminated byCO_2. But CeO_2 would suppress the decomposition of methane over Ni crystallite. Both La_2O_3 andCeO_2 can inhibit aggregation of the Ni particles. Decomposition of methane over the Ni-basedcatalysts is structure sensitive to a certain extent.

关键词： methane carbon dioxide nickel lanthana ceria

Influence of[La（EDTA）]-on pore structure of activated alumina carrier at high-temperature

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Influence of[La（EDTA）]-on pore structure of activated alum...