Preparation and Characterization of Component Materials for Intermediate Temperature Solid Oxide Fuel Cell by Glycine-Nitrate Process

La1-xSrxGa1-y MgyO3-δ(LSGM) electrolyte, La1-xSrxCr1-y MnyO3-δ( LSCM ) anode and La1-xSrxFe1-y MnyO3-aaaaaaa(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.

Synthesis and electrochemical properties of Li_2MnSiO_4/C nanoparticles via polyol process

Carbon-coated lithium manganese silicate （Li2MnSiO4/C） nanoparticles were synthesized by polyol process. X-ray diffraction （XRD） patterns of the obtained materials exhibit a good fit with that of the Li2MnSiO4 phase. Field emission scanning electron microscopy （FESEM） images of the obtained samples show that the particle size is only tens of nanometers. The high resolution transmission electron microscopy （HRTEM） analysis shows that the Li2MnSiO4 nanoparticles are surrounded by a very thin film of amorphous carbon. The composite prepared through polyol process shows good performance as cathode materials in lithium cells at room temperature. The charge capacity of the Li2MnSiO4/C samples is 219 mAh/g （about 1.3 Li^＋ per unit formula extracted）, and the discharge capacity is 132 mAh/g （about 0.8 Li^＋ per unit formula inserted） in the first cycle in the voltage range of 1.5-4.8 V. A good capacity cycling maintenance of 81.8% after 10 cycles was obtained.

Composition,Processing Technology and Property of Ceramic Die Materials Containing Rare Earth Additives

Development and application of new ceramic die materials is one of the important topics in the field of die research. The composition, processing technology, mechanical property and engineering performance of the ceramic materials such as cermet, ZTA, TZP, TZP/Al2O3, TZP/TiC/Al2O3, PSZ and Sialon, etc., with rare earth yttrium, lanthanum and cerium, and so on working as additives, were investigated and analyzed in the present study. Problems existed in the research and application of rare earth ceramic die materials were discussed. Rare earth additives can effectively improve the mechanical property and engineering performance of ceramic die materials. Thus, it will have further perspectives of wider application. More attention should be paid in the future to the toughening and strengthening of the ceramic die materials, the adding forms and kinds of rare earth elements and acting mechanisms of rare earth additives in ceramic die materials.

Influence of thermomechanical processing on the structure and properties of Cu-Ag alloy in situ composites

The influences of the thermomechanical processing, including the solidification conditions, the cold deformation and the intermediate annealing treatment, on the structure and properties of the Cu-10Ag alloy in situ composite were studied in this paper. The cast structure and the structural changes in the cold deformation and intermediate annealing process were observed. The properties including the ultimate tensile strength (UTS) and the electrical conductivity were determined. A two-stage strain strengthening effect for the Cu-10Ag alloy in situ filamentary composite was observed. The factors influencing the UTS and conductivity were discussed. The solidification conditions in the range of 10-1000 K/s cooling rates and the intermediate heat treatment showed obviously influence on the structure and properties on the Cu-10Ag alloy in situ filamentary composite. The typical properties of the Cu-Ag alloy in situ filamentary composites through thermomechanical processing were reported.

Preparation and properties of Ce_(0.8)Ca_(0.2)O_(1.8) anode material by glycine-nitrate process

Ce0.8Ca0.2O1.8 (CDC82) anode material was prepared by glycine-nitrate process(GNP). Thermogravimetric(TG) analysis and differential scanning calorimetric(DSC) methods were adopted to characterize the reaction process of CDC82 material. X-ray diffractometry(XRD), scanning electron microcopy(SEM), direct current four probe (four-probe DC) and temperature process reduce(TPR) techniques were adopted to characterize the properties of CDC82 material. After the precursor was sintered at 750 ℃ for 4 h, CDC82 material with pure-fluorite structure and nanometer size was obtained. The total conductivity of CDC82 changes little with temperature in air at 50?850 ℃ , and the maximum value is 0.04 S/cm at 750 ℃ . The total conductivity wholly becomes larger when the atmosphere changes from air to hydrogen, which greatly increases with increasing temperature and reaches the maximum value of 1.09 S/cm at 850 ℃. Some impurities such as CeMg and La2O3 exist after the mixture of CDC82 anode and La1?xSrxGa1?yMgyO3?δ (LSGM) electrolyte material is sintered at 1 200 ℃ for 15 h. The CDC82 material as anode material has excellent catalytic property for hydrogen and methane.

Influence of material processing on crystallographic and electrochemical properties of cobalt-free LaNi_(4.95)Sn_(0.3) hydrogen storage alloy

The effects of the alloy preparation methods, including the conventional casting, annealing and melt-spinning, on the crystallographic and electrochemical properties of the Co-free LaNi4.95Sn0.3 alloy samples were investigated. The results reveal that the as-cast alloy consists of a main phase of CaCu5-type structure and a little second phase (Sn) with noticeable composition segregation and rather poor cycling stability (S200=40.1%). While the annealed and melt-spun alloys are of single CaCu5-type structure phase with a more homogeneous composition and lower cell volume expansion rate (?V/V) on hydriding, and a dramatically improved cyclic stability (S200=73.6%?76.2%), although their activation rate, initial capacity and high-rate dischargeability are lowered somewhat. It is found that the decrease in both the electrocatalytic activity and the hydrogen diffusion rate of the annealed and melt-spun alloys is the main cause for their relatively lower high-rate dischargeability, and the improved cycling stability is due to their lower volume expansion on hydriding and more uniform composition.

Electromagnetic and microwave absorbing properties of W-type barium ferrite doped with Gd^(3+)

W-type barium ferrites doped with Gd^3＋,Ba1-xGdx（Zn0.3Co0.7）2Fe16O27（x = 0,0.05,0.10,0.15,0.20）,were prepared by a sol-gel method.The effects of Gd^3＋ substitution on their microstructure,electromagnetic properties and microwave absorptive behavior were analyzed.The XRD patterns showed the single phase of W-type barium ferrite when x ≤ 0.15.Microwave electromagnetic properties of samples were studied at the frequency range from 2 GHz to 18 GHz using a network analyzer（Agilent 8722ET）.The complex permittivity ε（ε＇,ε＇＇） increased gradually when x ≤ 0.10,but it decreased as x = 0.15.The real permeability（μ＇） decreased with the increase of Gd^3＋ content,while the imaginary permeability（μ＇＇） increased when x ≤ 0.10.All these reasons were discussed using the electromagnetic theory.Furthermore,the ferrite-epoxy compound coating materials with 80 wt.% of Ba0.9Gd0.1（Zn0.3Co0.7）2Fe16O27 were prepared to measure the microwave absorbing properties.The maximum of reflection loss（RL） reached about-27 dB and RL was below-10 dB in the frequency range of 8-18 GHz when the thickness was 1.92 mm.

Preparation and Physical Properties of Ceramsite Filter Media for Water Treatment Obtained from Municipal Solid Wastes

Sludge,solid waste of sewage treatment plants,poses a threat as a secondary pollution if it is not handled properly.In this study,artifical ceramsite filter material(ACFM)for water treatment,was obtained from sludge by high-temperature sintering process,and then it’s physical properties,leaching toxicity and sintering mechanisms were investigated.The results showed that the preferred conditions for the preparation of ACFM were that the mass ratio of sludge,river sediment and fly ash was 5∶4∶1,preheated at 400℃for 20 min and sintered at 1 150℃for 5 min.After the optimal sintering conditions treatment,the physical properties of the rate of breaking and wear,solubility in hydrochloric acid,silt carrying capacity,void fraction and Brunauer-Emmett-Teller(BET)specific surface area of ACFM were 0.2%,0.01%,0.2%,71.1%and 0.75×104cm2/g,respectively.The results confirmed that the ACFM’s physical properties were totally aligned to the requirements of China’s industry standard(CJ/T 299—2008).The leaching toxicity results indicated that the leaching contents of heavy metals,such as Cr,Zn and Cu,were much lower than the thresholds of China’s national standards(GB 5085.3—2007 and GB 8978—1996).

MEASUREMENTAL RESEARCH ON THE MAGNETOMECHANICAL COUPLING PROPERTIES OF RARERARTH GIANT MAGNETOSTRICTION MATERIALS

The physical modelanditsequivalentcircuitoftestapparatusissetup by meansofimpedanceanalysis method. The magnetostriction coefficient, magnetomechanicalcoupling coefficient,frequency and anti- frequency of TbxDy1 - xFe2 - z(0 27 ≤x ≤0 3 ,0 ≤z ≤0 1) rod are measured. Somecoupling problems with mechanicalstress and electromagnetic field such as flux leakage in magnetic path are discussed. The comparing calculated with tested resultsshowsthe accuracyof measurementand thesimplification of model.

Electrochemical properties of spinel compound LiNi_(0.5)Mn_(1.2)Ti_(0.3)O_4 as cathode materials for lithium ion batteries

The electrochemical properties of spinel compound LiNi0.5Mn1.2Ti0.3O4 were investigated in this study.The chemicals LiAc·2H2O,Mn（Ac）2·2H2O,Ni（Ac）2·4H2O,and Ti（OCH3）4 were used to synthesize LiNi0.5Mn1.2Ti0.3O4 by a simple sol-gel method.The discharge capacity of the sample reached 134 mAh/g at a current rate of 0.1C.The first and fifth cycle voltammogram almost overlapped,which showed that the prepared sample LiNi0.5Mn1.2Ti0.3O4 had excellent good cycle performance.There were two oxidation peaks at 4.21 V and 4.86 V,and two reduction peaks at 4.55 V and 3.88 V in the cycle voltammogram,respectively.By electrochemical impedance spectroscopy and its fitted result,the lithium ion diffusion coefficient was measured to be approximately 7.76 × 10？11 cm2/s.

Piezoelectric and dielectric properties of Cr-doped PSN-PZN-PZT qua-ternary piezoelectric ceramics

PSN-PZN-PZT + x wt. %Cr2O3, X = 0.0-0-9, were prepared by conventional mixed oxide techniques at sintering temperatures of 1220 degrees C-1300 degrees C for 2 h. The effect of sintering temperature on the microstructure and the piezoelectric properties was investigated by XRD, SEM, and other conventional measurement. The result indicated that with temperature increasing, the valence of Cr ion from Cr5+ or Cr6+ changes into C3+, and the piezoelectric properties turn hard. With increasing Cr2O3 content, the amount of rhombohedral phases increases and the morphotropic boundary phase is correspondingly shifts to rhombohedral phase. A uniform microstructure and excellent comprehensive properties were obtained at 1240 degrees C as the amount of Cr2O3 is 0.5 wt.%.

Coupled models of heat transfer and phase transformation for the run-out table in hot rolling

Mathematical models are been proposed to simulate the thermal and metallurgical behaviors of the strip occurring on the run-out table(ROT) in a hot strip mill. A variational method is utilized for the discretization of the governing transient con-duction-convection equation,with heat transfer coefficients adaptively determined by the actual mill data. To consider the thermal effect of phase transformation during cooling,a constitutive equation for describing austenite decomposition kinetics of steel in air and water cooling zones is coupled with the heat transfer model. As the basic required inputs in the numerical simulations,thermal material properties are experimentally measured for three carbon steels and the least squares method is used to statistically derive regression models for the properties,including specific heat and thermal conductivity. The numerical simulation and experimental results show that the setup accuracy of the temperature prediction system of ROT is effectively improved.

Performance of La_(1-x)Sr_xCr_(1-y)Mn_yO_(3-δ) anode materials for intermediate temperature solid oxide fuel cell

La1-xSrxCr1-yMnyO3-δ(LSCM) anode materials were synthesized by glycine nitrate process(GNP). Thermo-gravimetric analysis(TGA) and differential scanning calorimetric(DSC) methods were adopted to investigate the reaction process of LSCM anode materials. The oxides prepared were characterized via X-ray diffraction(XRD),scanning electron microscope and energy dispersive spectroscopy(SEM-EDS),direct current four-electrode and temperature process reduction(TPR) techniques. XRD patterns indicate that perovskite phase created after the precursor was sintered at 1 000 ℃ for 5 h,and single perovskite-type oxides formed after the precursor were sintered at 1 200 ℃ for 5 h. The powders are micrometer size after sintering at 1 000 ℃ and 1 200 ℃,respectively. The conductivities of LSCM samples increase linearly with increasing the temperature from 250 ℃ to 850 ℃ in air and the maximum value is 32 S/cm for La0.7Sr0.3Cr0.5Mn0.5O3-δ. But it is lower about two orders of magnitude in pure hydrogen or methane than that of the same sample in the air. TPR result indicates that LSCM offers excellently catalytic performance.

Wear behaviors and lubrication medium of TiC/Al_2O_3 ceramic wire drawing dies

The suitable test equipment for wire-drawing was designed. Wire-drawing tests were carried on with this equipment for TiC/Al2O3 ceramic wire-drawing die. Effect of lubrication medium and drawing velocity on the drawing force was investigated. The wear mechanisms of the ceramic drawing dies were investigated. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy. The results show that lubricant media have great influence on the drawing force. The drawing force is the smallest when a grease lubricant is used. But alteration of drawing velocity has scarcely any influence on the drawing force. Detailed observations and analyses of the die wear surface reveal that the most common failure of the ceramic drawing die is the wear in the invariable zone and bearing zone owing to the greater press stresses. Abrasive and adhesive wear are found to be the predominant wear mechanisms for ceramic drawing die.

硬质合金材料加工研究进展

硬质合金材料具有硬度高、强度高、化学稳定性强、冲击韧性高以及耐磨性好等优异材料特性,是现代工业生产以及新技术开发等领域中具有良好发展前景的工具材料和结构材料。但硬质合金材料的高脆性、低断裂韧性等缺陷使得硬质合金的机械加工性能非常差,成为其发展的重大阻碍,并且硬质合金加工表面易产生裂纹和凹坑,使工件表面质量下降并且影响加工性能,是典型难加工材料。本文对硬质合金的分类、性能及切削加工特点进行分析,并对硬质合金材料的加工研究现状和各种加工工艺方法的优缺点、发展趋势、存在问题及其对硬质合金表面质量的影响进行研究总结,以期为精密高效加工硬质合金提供参考依据。

多组分多层级3D打印材料研究进展

多组分多层级3D打印材料(McMl3DPMs)是一种新兴的先进材料,源于多孔材料、复合材料和增材制造的融合。由于增材制造赋予了Mc Ml3DPMs三维架构跨越广泛组分构成和结构类型的能力,Mc Ml3DPMs拥有杰出的机械性能,甚至是通常被认为相互排斥的性能(例如高强度和高韧性)。本文重点介绍为了实现高性能结构用Mc Ml3DPMs所必须解决的科学挑战以及最近研究工作对此做出的努力,将从结构设计、制造过程建模、缺陷表征和性能评价3个方面对相关案例进行回顾。最后,本文指出了当前研究的不足之处,并展望了Mc Ml3DPMs的未来发展,包括讨论了进一步推进这一新兴领域发展的几个可能的研究方向。

金属基石墨烯复合材料的合成机理及工艺方法

石墨烯具有良好的力学性能、导电导热和耐腐蚀性能,大部分纯金属只有在某些方面有着单一的良好性能,而不具备多维度的优良材料性能,金属基复合材料可以弥补纯金属在单一方面性能的不足,具有比单一基体更优异的性能;石墨烯/金属基复合材料(Gr-MMC)在航空航天、汽车、电子和军事领域有着广泛的应用。详细介绍了微观层面金属基表面沉积石墨烯的机理,在不同的金属表面石墨烯会表现出不同的行为,其中铜、钌、铱、镍是比较有代表性的几种金属,通过研究在不同金属上的沉积机理能够更好地从微观层面指导金属基复合材料的制备;金属基石墨烯复合材料的制备工艺针对不同的金属大致可以分为液相法、固相法和沉积处理,对于每种工艺方法的特点和不足也有所提及。

国产BE100和国外Wikus硬质合金带锯条背材的性能对比分析

以国产BE100和国外Wikus两种硬质合金带锯条背材为研究对象,采用光学显微镜、扫描电镜(SEM)、X射线衍射仪(XRD)和维氏硬度计等研究了背材的微观组织、物相及硬度,使用拉伸试验机和疲劳试验机测试其拉伸性能和疲劳性能,对比研究了两种背材的微观组织和力学性能。结果表明:两种背材的主要成分Fe、Cr和Ni均以单相固溶体存在,且背材中形成的碳化物均为非晶态;相比BE100背材,Wikus背材采用高温淬火和低温回火的热处理工艺,产生了马氏体固溶强化效果,获得了更高的硬度;BE100和Wikus背材的微观组织分别由回火索氏体和回火屈氏体组成,Wikus背材微观组织的均匀性更好;拉伸初始时BE100背材的塑性优于Wikus背材,但随应变量增至10%则低于Wikus背材,BE100背材比Wikus背材更早出现颈缩现象;此外,Wikus背材比BE100背材具有更好的疲劳稳定性。

热处理工艺对40CrNiMoA合金组织及力学性能的影响

为了提高矿用链轮耐磨性,延长其使用寿命,选取电渣离心铸造40CrNiMoA合金链轮件作为母材,研究热处理工艺对40CrNiMoA合金组织和力学性能的影响。采用正交试验法,研究不同热处理工艺对合金显微硬度、摩擦磨损及拉伸强度等力学性能的影响,并将测试结果进行极差分析和综合加权评分计算,得出最优热处理工艺参数,最后进行试验验证。结果表明,正交试验法得到的最优热处理工艺为880℃淬火0.5 h,600℃高温回火2 h,样品热处理后的组织主要为回火索氏体,维氏硬度为364 HV,抗拉强度为1166 MPa,磨损率为0.427×10^(-4)mm^(3)/(N·m);验证试验结果与正交试验分析结果相近,且热处理后的样品性能可达到使用要求。研究结果可为矿用链轮件热处理工艺提供理论依据,对有效解决链轮耐磨性和使用寿命问题具有参考价值。