Effect of Fe2O3 Loading Amount on Catalytic Properties of Monolithic Fe2O3/Ce0.67Zr0.33O2 -Al2O3 Catalyst for Methane Combustion

Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.     

Cu／Fe准周期超晶格的磁性

通过穆斯堡尔谱、振动样品磁强计和提拉样品磁强计对Ｃｕ／Ｆｅ一维准周期金属超晶格（ＤＱＰＭＳＬ）样品的磁性进行了研究。穆斯堡尔谱实验结果表明，居里点高于室温的ＯＱＰＭＳＬ样品在室温下呈现顺磁性而在低温（７７Ｋ）下呈现铁磁性，出现所谓超顺磁现象。进一步分析表明，超顺磁性的存在使得造成磁偶极分裂的磁场数值较小、超精细场减弱。其它实验数据证实了穆斯堡尔谱的分析结果。     

Effects of Cerium on Reduction of Non-Chromium Iron Based CO Shift Catalyst

ＣＯｓｈｉｆｔｐｒｏｃｅｓｓｉｓｏｎｅｅｓｓｅｎｔｉａｌｐｒｏｃｅｓｓｉｎｔｈｅｃｈｅｍｉｃａｌｆｅｒｔｉｌｉｚｅｒｉｎｄｕｓｔｒｙａｓｗｅｌｌａｓｏｔｈｅｒｉｎｄｕｓｔｒｙ .Ｉｎｔｈｅｐｒｅｓｅｎｔｔｉｍｅ ,ｔｈｅｉｒｏｎｃａｔａｌｙｓｔｓｃｏｎｔａｉｎｉｎｇｃｈｒｏｍｉｕｍｉｓｓｔｉｌｌｗｉｄｅｌｙｕｓｅｄｉｎｉｎｄｕｓｔｒｙ .Ａｓｔｈｅｒｅａｓｏｎｐｏｉｎｔｅｄｏｕｔｉｎｔｈｅｐｒｅｖｉｏｕｓａｒｔｉｃｌｅ[1] ,ｔｈｅｒｅｉｓａｇｒｅａｔｉｎｔｅｒｅｓｔｉｎｔｈｅｗｏｒｌｄｔｏｄｅｖｅｌｏ…     

Cu-Mn catalysts modified by rare earth lantnaum for low temperature water-gas shift reaction

The Cu-Mn catalysts doped with different amounts of lanthanum(La) for water-gas shift reaction(WGSR) were prepared, and characterized by X-ray diffraction(XRD), temperature-programmed reduction(TPR), temperature-programmed reduction of oxidized surfaces(s-TPR), temperature-programmed desorption of CO_2(CO_2-TPD), infrared spectrum(FT-IR) and X-ray photoelectron spectroscopy(XPS). Catalytic activities were tested for a water-gas shift reaction. The results showed that the introduction of 0.5 mol.% La could significantly improve the catalyst activity for low-temperature shift reaction compared with the undoped catalyst, which might be from the introduction of La making the Cu and Mn components distribute uniformly and the synergistic effect between Cu and Mn increasing the dispersion of Cu on the surface of the catalyst. The apparent CuO phases besides Cu_(1.5)Mn_(1.5)O_4 were found in the samples with at least 3.0 mol.% La content, and the basic sites increased with the increasing of La contents at a decreased rate. With excessive La doping, La particles would aggregate and cover some active sites, resulting in that Mn could not effectively inhibit the gathering together and growing up of Cu crystalline grain, and decreased the dispersion of Cu on the surface, which resulted in the poor activity of the catalyst for WGSR.     

Sol-Gel Synthesis of LaMO3 (M = Cr, Mn, Fe, Co, Ni) Nanocrystalline Powders

Sol-gel synthesis of LaMO3 ( M = Cr, Mn, Fe, Co, Ni) nanocrystalline Powders was investigated. DSC measurement shows that precursors decomposed at about 403 K and 620 K to bum out of N, C, and H. The calcined samples at 1073 K were determined by XRD to be single phase. SEM observation shows that the prepared samples are nanocrystalline powders in broad sense. The average grain size of LaM'O3 (M'= Cr, Mn, Fe, Ni) is 150 ～700 nm,and the grain size of LaCoO3 is about 30 nm.     

电感耦合等离子体原子发射光谱法测定钒铬钛合金中11种元素

以V₂O₅、Cr₂O₃和TiO₂直接还原熔炼钒铬钛合金的新工艺具有显著降低生产成本优势,但需解决原料、还原剂以及熔炼设备所引入杂质对产品品质的影响,为此,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定V-4Cr-4Ti合金中Al、As、Co、Cu、Fe、Mg、Mn、Ni、P、K、Na等11种微量杂质元素分析方法。方法重点考察了在V、Cr、Ti三元合金组分共存体系下,基体效应、光谱干扰和连续背景叠加等影响因素,归纳了基体及共存组分对待测元素高灵敏分析谱线的光谱干扰情况,优选了待测元素的分析谱线、背景校正区域以及光谱仪工作条件等参数。采用基体匹配和同步背景校正法消除高V、高Cr和高Ti共存基体的影响。结果表明:Al、As、Co、Cu、Fe、Mg、Mn、Ni、P的检测范围为0.001%~0.25%,K、Na的检测范围为0.002%~0.25%;校准曲线线性相关系数不小于0.9995,方法的测定下限为0.0012%(K)、0.0015%(Na)、0.0003%~0.0009%(其余元素)。按照实验方法测定4个V-4Cr-4Ti合金样品中Al、As、Co、Cu、Fe、Mg、Mn、Ni、P、K、Na,0.x%水平测定结果的相对标准偏差(RSD,n=8)小于5%,0.0x%~0.00x%水平测定结果的相对标准偏差(RSD,n=8)小于10%,即使低于方法检测下限0.001%水平测定结果的相对标准偏差(RSD,n=8)也小于15%。按照实验方法对4个V-4Cr-4Ti合金样品中Al、As、Co、Cu、Fe、Mg、Mn、Ni、P、K、Na进行加标回收试验,回收率为90%~114%。实验方法用于测定3个V-4Cr-4Ti合金样品中Al、As、Co、Cu、Fe、Mg、Mn、Ni、P、K、Na,与电感耦合等离子体质谱法(ICP-MS)测定结果相吻合。     

Electrical and Magnetic Properties of Bilayer Manganites La1.4Sr1.6Mn1.96TE0.04O7 （TE = Mn, Fe, Ti, Nb）

The electrical and magnetic properties of bilayer manganites La1.4Sr1.6Mn1.96TE0.04O7（TE = Mn, Fe, Ti, Nb） were investigated. Doping caused obvious changes in electrical and magnetic behaviors such as decrease of insulator-metal transition and magnetic transition temperatures, increase of peak resistivity, and different magnetoresistance effect. These changes had a significant degree of correlation with the valence of doped ions. From Fe, Ti to Nb doping, the effect was doubly stronger. The results could be well understood by considering the different destructions on double-exchange interaction and different influences on lattice distortion caused by Fe, Ti and Nb doping. The temperature dependence of magnetization measured at high field showed that the influence of doping was greatest near three-dimensional magnetic transition temperature of parent phase.     

Flow Stress and Critical Dynamic Recrystallization Behavior of Cu–Fe16Mn0.6C High Manganese TWIP Steel

The true stress–strain curve of Cu–Fe16Mn0.6C twinning induced plasticity (TWIP) steel was studied with a compression test on Thermecmastor‐Z thermal simulator at a temperature range of 850–1150°C and strain rate range of 0.03–30 s^?1. The influence of deformation temperature and strain rate on high‐temperature flow stress and critical recrystallization behavior of the TWIP steel was investigated. It is concluded that the peak flow stress of Cu–Fe16Mn0.6C under high‐temperature deformation decreases as the temperature increases but increases with the strain rate. Meanwhile at strain rate of 0.03 and 30 s^?1 obvious peak stresses are observed which demonstrates the dynamic recrystallization. The constitutive equation of Cu–Fe16Mn0.6C under high temperature deformation is calculated by linear regression method. The activation energy is 505 kJ mol^?1. The relationship between critical strain of dynamic revrystallization and Zener–Hollomon parameter is determined by the curve between strain‐hardening rate and flow stress.     

Effect of Ceria on Structure and Thermostability of Copper-Iron-Oxide Catalyst

Ｃｏｐｐｅｒｏｘｉｄｅａｎｄｉｒｏｎｏｘｉｄｅａｒｅｔｒａｄｉｔｉｏｎ ａｌｏｘｉｄｉｚｉｎｇｃａｔａｌｙｓｔｓ.Ｔｈｅｉｒｍｉｘｔｕｒｅｓａｒｅｇｏｏｄｃａｔａｌｙｓｔｓｆｏｒｔｈｅｐｕｒｉｆｉｃａｔｉｏｎｏｆｗａｓｔｅｇａｓｅｓ,ｅｓ ｐｅｃｉａｌｌｙｅｘｃｅｌｌｅｎｔｆｏｒｃａｔａｌｙｚｉｎｇｔｈｅｒｅｄｕｃｔｉｏｎｏｆｎｉｔｒｏｇｅｎｏｘｉｄｅｂｙｃａｒｂｏｎｏｘｉｄｅａｎｄｔｈｅｏｘｉ ｄａｔｉｏｎｏｆｎｉｔｒｏｇｅｎｏｘｉｄｅｂｙｏｘｙｇｅｎ .Ｒｅｃｅｎｔｒｅ ｓｕｌｔｓａｂｏｕｔｔｈｅｓ…     

Activity and diffusivity measurements of copper in γ and δ Fe by equilibration between solid Fe and liquid Ag

The activities of Cu in solid Fe for 1323 <=T <= 1773 K have been determined by equilibrating the surface of initially pure Fe plates with liquid Ag-Cu alloys and by using the literature values of the Cu activity in Ag-Cu alloys. The equilibrations have been confirmed by the agreement of surface compositions between an initially pure Fe plate and an Fe-Cu alloy plate having more content of Cu than the surface concentration. The equilibrated Fe plates were essentially binary Fe-Cu alloys, because no Ag was detected by an electron probe analyzer in the Fe plates. Interdiffusivities in solid Fe-Cu alloys for the same temperature range have also been determined from penetration profiles of Cu in the plates. The ternary phase diagram for the Ag-Cu-Fe system at 1480 K has been determined from solubility measurements of Fe in liquid Ag-Cu alloys. M. Tanaka, formerly at Tokyo Institute of Technology, is now with Clinap Industries, Tokyo, Japan.     

Fe2O3、Cr2O3掺杂对4YSZ导电性能的影响

用柠檬酸溶胶-凝胶法制备了分别掺Fe2O3和Cr2O3的4YSZ前驱体凝胶,凝胶在500℃预烧,压制成圆片状后在1 300℃煅烧2 h得到所需试样;分别研究Fe2O3、Cr2O3的不同掺量对试样的烧结性能、电导率的影响。结果表明掺Fe2O3可提高试样的电导率和烧结性能;掺Cr2O3可提高试样的低温电导率,但使试样的烧结性能下降。     

Study of Physicochemical Properties and Active Oxygen in Structures of Layered Mixed La_4BaCu_5-_xM_xO_(13 λ)(M=Mn,Co)

ＴｈｅｒｅｉｓｐｒｏｆｕｓｅｒｅｓｏｕｒｃｅｏｆｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｉｎＣｈｉｎａ,ｓｏｉｔｉｓｖｅｒｙｉｍｐｏｒｔａｎｔｔｏｓｔｕｄｙｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｒａｒｅｅａｒｔｈｃｏｍｐｏｕｎｄｓ［１］．Ｔｈｅｐｅｒｏｖｓ...     

纳米晶Fe3Al材料的抗腐蚀性能和高温抗氧化性能

通过铝热反应熔化法制备纯纳米晶Fe3Al材料以及添加质量分数分别为10％Ni,10％Cr,10％ Mn,15％ Mo,5％ Cu和10％Cu合金元素的6种块体纳米晶Fe3Al材料;对含10％ Ni的纳米晶Fe3Al材料分别进行600 ℃、1000℃,8h的等温处理.采用质量损耗法测定不同纳米晶Fe3Al材料在质量分数为5％ H2SO4溶液中的均匀腐蚀速率;并研究各纳米晶Fe3Al材料在1200℃空气中的高温氧化性能.结果表明:添加15％Mo和添加10％Cu的纳米晶Fe3Al材料较纯纳米晶Fe3Al材料抗腐蚀性能提高明显;含10％ Ni的纳米晶Fe3Al材料经过600℃ 等温处理后的腐蚀速率略高于未等温处理的材料,而经1000℃等温处理后腐蚀速率明显下降;随着合金元素Ni、Mn、Cr、Cu的加入,纳米晶Fe3Al材料的氧化速度增大,抗氧化性能降低.     

ICP-AES法连续测定土壤样品中的铜、铅、锌、铁、锰

采用混酸溶解土壤样品,用ICP - AES法连续测定铜、铅、锌、铁、锰五种元素,对比了三种消解体系,优化了盐酸复溶体系,优化了仪器的使用条件,方法检出限为Cu 3.31 μg·g-1、Pb 8.95μg·g-1、Zn 4.22 μg·g-1、Fe 3.85μg·g-1、Mn4.15 μg·g-1.在加标回收实验中,相对标准偏差为2.81％ ～3.92％ (n=10),方法回收率为96.2％ ～ 104.0％.用于分析矿石样品,分析结果与推荐值相符,可用于地质实验室对大量矿石样品的检测.     

原子吸收法连续测定钛粉中微量Fe,Sb,Mn,Cu,Ca和Mg

用HCl-H2 O2 溶解试样 ,在几个相同量的试液中 ,分别加入浓度依次递增的 6种元素的标准溶液 ,用空气 -乙炔火焰原子吸收法连续测定Fe,Sb ,Mn ,Cu ,Ca和Mg的含量。建立了优化的仪器测定条件 ,并对可能存在的元素进行了干扰试验。铁等 6种元素的回收率为 97.8%～ 10 3. 7% ,相对标准偏差为 1.9%～ 3.5 %。     

Calculation of phase diagrams of systems Al-Cu-Zn-Mg and Al-Cu-Zn-Mg-Fe-Si

Fragments of phase diagrams Al-Cu-Zn-Mg and Al-Cu-Zn-Mg-Fe-Si-(Mn) in a temperature range (%) 4–6 Cu, 2–4 Zn, 0.5–2.0 Mg, 1.5–2.0 Fe, and 1.5–5.0 Si are constructed and the composition of the solid solution for a series of alloys of the Al-Cu-Zn-Mg-Fe-Si-(Mn) system at temperatures near the solidus is calculated by the results of thermodynamic calculations using the ThermoCalc software package. The thermodynamic calculations are verified by electron probe microanalysis. This verification shows the satisfactory convergence of the calculated and experimental data. It is revealed that, with the ratio of iron and silicon concentrations Fe/Si = 0.5 for alloys of the Al-Cu-Zn-Mg-Fe-Si-(Mn) system, it is possible to obtain a maximally doped solid solution.     

Investigation of the Effects of Ni, Fe, and Mn on the Formation of Complex Intermetallic Compounds in Al-Si-Cu-Mg-Ni Alloys

The aim of this work is to partially substitute Fe and Mn for Ni in the 3HA piston alloy and to study the consequences through microstructural evaluation and the thermal analysis technique. Three types of near-eutectic alloys containing (2.6 wt pct Ni-0.2 wt pct Fe-0.1 wt pct Mn), (1.8 wt pct Ni-0.75 wt pct Fe-0.3 wt pct Mn), and (1 wt pct Ni-1.15 wt pct Fe-0.6 wt pct Mn) were produced, and their solidification was studied at the cooling rate of 0.9 K/s (°C/s) using the computer-aided thermal analysis technique. Optical microscopy and scanning electron microscopy were used to study the microstructure of the samples, and energy dispersive X-ray (EDX) analysis was used to identify the composition of the phases. Also, the quantity of the phases was measured using the image analysis technique. The results show that Ni mainly participates as Al₃Ni, Al₉FeNi, and Al₃CuNi phases in the high Ni-containing alloy (2.6 wt pct Ni). In addition, substitution of Ni by Fe and Mn makes Al₉FeNi the only Ni-rich phase, and Al₁₂(Fe,Mn)₃Si₂ appears as an important Fe-rich intermetallic compound in the alloys with the higher Fe and Mn contents.     

ICP—OES法测定铝铁中的铝锰硅磷铜铁含量

用稀王水溶解试样,ICP—OES法直接测定铝铁中的铝、锰、硅、磷、铜、铁的含量。对样品溶解酸度、元素谱线选择、背景校正扣除、样品基体及待测元素间干扰等因素进行了试验研究。采用基体匹配与背景扣除法消除基体对待测元素的光谱干扰,确定了最佳实验条件。结果表明：各元素的加标回收率为96．0％～105．0％,相对标准偏差小于2．50％。本法与化学分析方法对照,测定结果一致,已用于铝铁产品的检验。     

Liquidlike sintering behavior of nanometric Fe and Cu powders: Experimental approach

Nanometric Fe and Cu powders were sintered in vacuum, He, and H₂ atmospheres after uniaxial cold pressing. The shrinkage behavior of samples was studied using three different dilatometric techniques: constant heating rate, isothermal annealing, and the Dorn method. Density greater than 90 pct was obtained at sintering temperatures of 900 °C. In nanometric powders, densification and grain coarsening occurred in a narrow temperature interval. Despite the low oxide content in the starting powders (1.5 to 4 wt pct), the reducing atmosphere plays a relevant role in the sintering process. The self-diffusion activation energies obtained for nanometric Fe were 116 and 60 kJ/mole in vacuum and H₂, and those obtained for nanometric Cu were 70 and 43 kJ/mole in He and H₂. According to the present results, the activation energies obtained from both nanometric powders in H₂ could be associated with those for self-diffusion in liquid Fe (65 kJ/mole) and Cu (41 kJ/mole).     

直接置换法制备包覆型铁铜双金属粉末的工艺研究

以还原铁粉为核心, 以硫酸铜为铜源, 采用直接置换法初步制备包覆型铁铜双金属粉末. 用扫描电子显微镜(SEM)和X射线衍射对粉末的形貌和结构进行了研究, 分析了添加剂、反应时间、干燥还原条件对金属粉末特性的影响, 采用惰气脉冲红外热导法和湿热环境氧化模拟法对粉末的抗氧化性能进行了测试. 试验结果表明: 铁铜双金属粉末为包覆型结构, 添加剂的加入有利于形成致密包覆层, Cu层厚度约为1 μm; 反应时间在25～30 min范围内, 金属收得率最高达到99.5%; 较合适的干燥还原条件应为: 温度在500～650 ℃之间, 时间2～3 h. 在粉末中加入抗氧化剂后, 有效地解决了粉末的氧化问题; 粉末由Cu和Fe两相构成, 没有其他杂质相, 铜的含量为19.53%. 并对大量硫酸亚铁上清液的处理提出了新的方法. 硫酸亚铁上清液可以作为生产金刚石工具用的超细Fe基预合金粉末的原料, 此方法具有简单合理、成本低、环保、产品附加值高的优点.