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Journal of rare earths 2010年第S1期28卷 338-342页

作者：段开娇唐晓龙易红宏宁平王文琴 College of Environmental Science and Engineering Kunming University of Science and Technology College of Mechanical and Electrical Engineering Kunming University of Science and Technology

Selective catalytic oxidation(SCO) of ammonia was carried out over Cu-Mn compounds catalysts modified with trivalent rare earth oxide Ce2O3 and La2O3 ***2 was used as support and different ratio of O2 were tested in order to find an appropriate O2 concentration(vol.%),and the results showed that 1%O2(vol.%) was propitious to SCO of *** effects of the two rare earth oxides modified catalysts Ce2O3-Cu-Mn/TiO2 and La2O3-Cu-Mn/TiO2 on the catalytic activity and selectivity of ammonia oxidation were investigated under the reaction condition of 500 ppm ammonia,1%O2(vol.%),at the temperature from 125 to 250 *** results revealed the beneficial role of Ce2O3 and La2O3 in catalytic activity at low temperature and lean oxygen concentration,while the modification with Ce2O3 and La2O3 led to the negative influence on N2 *** the catalysts modified with Ce showed lower NO and N2O selectivity than the catalysts modified with La,then the effects of different Ce loadings on catalytic activity and selectivity were also considered,in combination with catalysts preparation methods,which include incipient wet impregnation,sol-gel method and *** revealed that the catalysts prepared by sol-gel method obtained preferable catalytic activity compared with the others,reaching 99% ammonia at 200 oC,whereas 96% NO was *** also indicated that different catalyst preparation method significantly determined production distribution.

关键词： ammonia selective catalytic oxidation (SCO) rare earth oxide Cu-Mn compounds low temperature

Control of the hydrophobicity of rare earth oxide coatings deposited by solution precursor plasma spray by hydrocarbon adsorption

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Journal of Materials Science & Technology 2021年第3期62卷 107-118页

作者： Pengyun Xu Guohui Meng Larry Pershin Javad Mostaghimi Thomas W.Coyle Centre for Advanced Coating Technologies University of TorontoTorontoON M5S 3G8Canada

The basis of the hydrophobicity of lanthanide rare earth oxides(REOs)has been the subject of considerable *** explore this question,the wetting behaviors and surface compositions of hierarchicallystructured Yb_(2)o_(3)(one of the REOs)coatings and non-REO Al_(2)o_(3)coatings deposited via solution precursor plasma spray process were investigated in this *** Yb_(2)o_(3)coatings were subjected to a number of post-deposition treatments including vacuum(1-15 Pa)treatment,Ar-plasma treatment,heat treatment(400℃),long-time air exposure and ultra-high vacuum(1×10^(-7)Pa)*** characterization showed that different post-deposition treatments resulted in different wetting behavior for the Yb_(2)o_(3)coatings which correlated with the content of hydrocarbon on the ***_(2)o_(3)coatings exhibited reversible transitions between superhydrophobicity after vacuum treatment and superhydrophilicity after Ar-plasma or heat treatment,linked to hydrocarbon adsorption onto and desorption from the ***_(2)o_(3)coatings after long-time air exposure and ultra-high vacuum treatment both remained hydrophilic and showed a smaller hydrocarbon content than coatings after vacuum ***_(2)o_(3)coatings with hierarchical surface structures similar to the Yb_(2)o_(3)coatings showed an increase in WCA to only-170 after the same vacuum treatment,indicating the REO has a much higher affinity for hydrocarbon adsorption than Al_(2)o_(3),and that the content of hydrocarbon adsorbed on the surface of the REO determined the wetting behavior.

关键词： rare earth oxide Hydrophobicity Solution precursor plasma spray Post-deposition treatments

Effects of rare earth oxide on hardfacing metal microstructure of medium carbon steel and its refinement mechanism

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Journal of rare earths 2011年第6期29卷 609-613页

作者：郝飞飞廖波李达刘利刚淡婷任学军杨庆祥 State Key Laboratory of Metastable Materials Science and Technology College of Materials Science and Engineering Yanshan University School of Materials Science and Engineering Southwest Jiaotong University School of Engineering Liverpool John Moores University

The electrodes for hardfacing medium carbon steel with six additions of rare earth oxide were developed in this work. By means of optical microscopy and scanning electron microscopy, the microstructure, inclusion and the fractograph of the hardfacing metal were observed. Then, the effects of rare earth oxide on microstructure and inclusions in hardfacing metal were analyzed. The effectiveness of rare earth oxide as heterogeneous nuclei of δ-Fe was calculated with the misfit theory. The results showed that, the microstructure of hardfacing metal was composed of ferrite and small amount of pearlite. The microstructure was refined at first and then coarsened with the increase of rare earth oxide addition. The fractograph was changed from brittle to equiaxed dimples, then became quasi-cleavage and cleavage gradually. The calculated results showed that, the ferrite grain size could be refined because that LaAlO3 as heterogeneous nuclei of δ-Fe was moderately effective, and the ferrite grain size was coarsened because the misfits between Ce2O3 and δ-Fe, Ce2O2S and δ-Fe were increased with futher increase of rare earth oxide addition.

关键词： hard-face-welding metal rare earth oxide microstructure heterogeneous nuclei repair

Catalytic action of rare earth oxide(La_(2)O_(3),CeO_(2),Pr_(6)O_(11))on electrochemical oxidation of activated carbon in molten KOH-NaOH

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Journal of rare earths 2022年第7期40卷 1083-1090页

作者： Xiaofeng Li Yuanxing Dong Xiaohui Liu Lijun Li Yanfang Gao Zhenzhu Cao Jinrong Liu College of Chemical Engineering Inner Mongolia University of TechnologyHohhot 010051China

The oxidation of anode carbon fuel directly affects the electrochemical performance of molten hydroxide direct carbon fuel cell(MHDCFC).In general,the anode carbon fuel can be oxidized at high temperature,thus the direct carbon fuel cell(DCFC)can show great electrochemical *** this study,rare earth oxides(La_(2)O_(3),CeO_(2),Pr_(6)O_(11))were prepared by the method of *** carbon was prepared by pretreatment of *** earth oxides and activated carbon were mixed as anode carbon fuel,and rare earth oxides were used to catalyze the electrochemical oxidation of anode carbon *** results show that CeO_(2)has better electrocatalytic activity compared with La_(2)O_(3)and Pr_(6)O_(11) in the *** electrochemical test results show that the current density(at 0.4 V)increases from 81.02 to 112.90 mA/cm^(2)and the maximum power density increases from 34.78 to 47.05 mW/cm^(2)at 450℃,when the mass fraction of CeO_(2)is increased from 0 to 40%.When the mass fraction of CeO_(2)is 30%,the current density(82.55 mA/cm^(2)at 0.4 V)at 400℃is higher than that(81.02 mA/cm^(2)at 0.4 V)without CeO_(2)at 450℃.The electrochemical oxidation mechanism of CeO_(2)catalyzed anode carbon fuel is discussed.

关键词： rare earth oxide Catalysis Activated carbon Electrochemical oxidation Molten hydroxide direct carbon fuel cell

Effect of doping rare earth oxide on performance of copper-manganese catalysts for water-gas shift reaction

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Journal of rare earths 2014年第4期32卷 298-305页

作者：何润霞姜浩强武芳智科端王娜周晨亮刘全生 School of Chemical Engineering Inner Mongolia University of Technology

rare earth-doped copper-manganese mixed oxide catalysts were prepared by coprecipitation and mechanical mixing using copper sulfate, manganese sulfate, and rare-earth oxides REO （REO indicates La2O3, CeO2, Y2O3, or Pr6O11） as raw materials. The samples were characterized by X-ray diffraction （XRD）, temperature-programmed reduction （TPR）, temperature-programmed reduc-tion of oxidized surfaces （s-TPR）, and temperature-programmed desorption （TPD）. Catalytic activities were tested for a water-gas shift reaction. Doping rare earth oxides did not alter the crystal structure of the original copper-manganese mixed oxides but changed the interplanar spacing, adsorption performance and reaction performance. Doping with La2O3 enhanced the activity and stability of Cu-Mn mixed oxides because of high copper distribution and fine reduction. Doping with CeO2 and Y2O3 also decreased the reduc-tion temperatures of the samples to different degrees while improving the dispersion of Cu on the surface, thus, catalytic activity was better than that of undoped Cu-Mn sample. The Pr6O11-doped sample was difficult to reduce, the dispersion of surface coppers was lowered, resulting in poor activity.

关键词： rare earth oxide copper-manganese catalyst water-gas shift reaction stability

Mechanism of Cracking Resistance of Hardfacing Specimens of Steel 5CrNiMo Improved by rare earth oxide

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Journal of rare earths 2006年第4期24卷 471-478页

作者：杨庆祥任学军刘利刚李达董海峰廖波 Key Laboratory of Metastable Materials Science and Technology College of Materials Science and Engineering Yanshan University Qinhuangdao 066004 China School of Engineering Liverpool John Moores University Liverpool L3 3AF UK

The cracking morphology of the hardfacing specimens taken from steel 5CrNiMo was observed. Meanwhile, the residual stress fields were measured and simulated. Based on experiment mentioned above, the improved structure and modified inclusion in hardfacing metal with rare earth （RE） oxide were analyzed. The results show that, the hardfacing crack is initiated from the coarse dendritic crystal grain boundary, inclusions and coarse austenite grain boundary in the HAZ and propagated by the residual stress existing in the center of the hardfacing metal and HAZ. The primary columnar grain structure can be refined by adding RE oxide in the coating of the electrode. The inclusion in the hardfacing metal can be modified as well. Meanwhile, if the martensite transformation temperature is decreased, the largest value of the residual tensile stress in the dangerous region can be reduced.

关键词： green remanufacture hot forged die medium-high carbon steel hardfacing materials rare earth oxide

Laser cladding in-situ carbide particle reinforced Fe-based composite coatings with rare earth oxide addition

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Journal of rare earths 2009年第6期27卷 997-1002页

作者：吴朝锋马明星刘文今钟敏霖张红军张伟明 Key Laboratory for Advanced Materials Processing Technology Ministry of Education Department of Mechanical Engineering Tsinghua University

Particulate reinforced metal matrix composite(PR-MMC) has excellent properties such as good wear resistance,corrosion resistance and high temperature *** cladding is usually used to form PR-MMC on metal surface with various volume fractions of ceramic *** literatures showed that laser melting of powder mixture containing carbon and carbide-forming elements,was favorable for the formation of in-situ synthesized carbide *** this paper,rare earth oxide(RE2O3) was added into t...

关键词： laser cladding particle reinforced rare earth oxide nucleation rare earth carbide

Effects of rare earth oxide additives on the thermal behaviors of aluminum nitride ceramics

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rare Metals 2009年第6期28卷 596-599页

作者： YAO Yijun WANG Ling LI Chuncheng JIANG Xiaolong QIU Tai School of Mathematics and Physics Nanjing University of Information and Science Technology Nanjing 210044 China College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China

The effects of Y2O3 and Er2O3 on the sintering behaviors, thermal properties and microstructure of A1N ceramics were investigated. The experimental results show that the sintering temperature can be decreased; the relative density and thermal behavior can be improved by adding rare earth oxide in A1N ceramics. For A1N ceramics with 3 wt.% Er2O3 additive, the relative density is 98.8%, and the thermal conductivity reaches 106 W.m^-1.K^-1. The microstructure research found that no obvious aluminum erbium oxide was found in A1N ceramics doped with 3 wt.% Er203, which favored the improvement of the thermal conductivity of A1N ceramics.

关键词： alumina nitride rare earth oxide thermal behavior sintering

Roles of rare earth oxide additives in millimeter-wave sintering of AlN

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Journal of rare earths 2008年第2期26卷 141-145页

作者： Yukio Makino Takashi Yoshioka Hiromi Nakano Toshiyuki Ueno Shoji Miyake Osaka University 11-1 Mihogaoka IbarakiOsaka 567-0047 Japan Shimane Institute for Industrial Technology 1 Hokuryo-cho Matsue Simane 690-0816 Japan Ryukoku University Seta Otsu Shiga 520-2194 Japan Kinki University 3-4-1 Kowakae Higashi-OsakaOsaka 577-8502 Japan

Roles of rare earth oxide （RE2O3） additives in millimeter-wave（MM） sintering of AIN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AIN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE2Oa-Al2O3 binary system. The lowest densification temperature in the millimeter-wave sintering of AIN with Yb2O3 additive was attributed to the largest heating rate of Yb2O3-Al2O3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb2O3 content so as to form the intergranular phase with the eutectic composition in the Yb2O3-Al2O3 binary system. The result showed good agreement with the above mentioned during the sintering of Si3N4 with Yb2O3-Al2O3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb2O3 added AINs.

关键词： millimeter-wave rare earth oxide AIN, Si3N4 rapid densification selective heating heating rate thermal conductivity morphology

Synthesis and characterization of calcium and manganese-doped rare earth oxide La_(1-x)Ca_xFe_(0.9)Mn_(0.1)O_(3-δ) for cathode material in IT-SOFC

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Journal of rare earths 2011年第11期29卷 1066-1069页

作者：赵捷李晨孔令龙吴雪薇马永昌 School of Materials Science & Engineering Tianjin University of Technology Tianjin Key Lab for Photoelectric Materials and Devices Key Laboratory of Display Materials and Photoelectric Devices(Tianjin University of Technology) Ministry of Education

In order to develop novel cathode materials with high performance for intermediate temperature SOFC（IT-SOFC）,Ca and Mn doped rare earth oxides La1-xCaxFe0.9Mn0.1O3-δ（x=0.1,0.3 and 0.5,denoted as LCFM9191,LCFM7391 and LCFM5591） were synthesized by solid state reaction（SSR） *** formation process,phase structure and microstructure of the synthesized samples were characterized using thermogravimetry/differential scanning calorimetry（TG/DSC）,X-ray diffraction（XRD） and scanning electron microscopy（SEM）.The thermal expansion coefficients（TEC） of the samples were analyzed at 100-900 oC by thermal *** electrical conductivities of the samples were measured with direct current（DC） four-terminal method from 300 to 850 *** results indicated that the samples（x=0.1 and 0.3） exhibited a single phase with orthorhombic and cubic perovskite structure,respectively after being sintered at 1200 oC for 3 *** electrical conductivity of the samples increased with temperature up to a maximum value,and then *** small polaron hopping was regarded as the conducting mechanism for synthesized samples at T≤600 *** negative temperature dependence occurring at higher temperature was due to the creation of oxygen vacancies for charge ***7391 had higher mixed conductivity（100 S/cm） at intermediate temperature and could meet the demand of cathode material for *** addition,the average TECs of LCFM9191 and LCFM7391 were 11.9×10-6 and 13.1×10-6 K-1,respectively,which had good thermal match to the common electrolytes.

关键词： rare earth oxide solid state reaction perovskite structure mixed conductivity thermal expansion