Intermediate temperature solid oxide fuel cell based on fully integrated plasma-sprayed components

This work addresses the fabrication of membrane-type solid oxide fuel cells (SOFCs) operating at medium temperatures, where all components are fabricated by plasma spray technology, and the evaluation of the performance of the SOFC single unit in a temperature range of 500 to 800 °C. Single cells composed of LaSrMgO₃ cathodes, LaSrGaMgO₃ (LSGM) electrolytes, and Ni/yttria-stabilized zirconia anodes were fabricated in successive atmospheric plasma-spraying processes. Plasma-spraying processes have been optimized and tailored to each layer to achieve highly porous cathode and anode layers as well as high-density electrolyte layers. A major effort has been devoted to the production of the LSGM electrolyte that has a high density and is free of cracks. Electrochemical impedance spectroscopy was used to investigate the conductivity of the electrode layers, and particularly the resistance of the electrolyte layer. It revealed that the heat treatment had a great influence on the specific conductivity of the sprayed electrolyte layers and that the specific conductivity of the heat-treated layers was dramatically increased to the same magnitude as is typical for sintered LSGM pellets. The experimental results have demonstrated that the plasma-spraying process has a great potential for the integrated fabrication of medium-temperature SOFC units. The original version of this article was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International, 2003.     

PARTICLE SIZE AND MICROSTRUCTURE OF Ni NANOPOWDERS PREPARED BY ANODIC ARC PLASMA

Pure Ni nanopowders were successfully prepared by the method of anodic arc discharged plasma with homemade experimental apparatus. The particle size, mircostructure and morphology of the particles by this process were characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED); The specific surface area and pore parameters were investigated by multi-point full analysis of nitrogen adsorption-desorption isotherms at 77K by BrunauerEmmett-Teller (BET) surface area analyzer; The chemical composition were determined by X-ray energy dispersive spectrometry (XEDS) equipped in SEM and element analyze instrument. The experiment results indicate that the samples by this method with high purity, the crystal structure of the particles is as same as the bulk material, is fcc structure, with average particle sizes about 47nm, ranging from 20 to 70nm, and distributed uniformly in spherical chain shapes, the specific surface areavis 14.23m^2/g, pore volume of pore is 0.09cm^3/g and average pore diameter is 23nm.     

Effects of particle arrangement and particle damage on the mechanical response of metal matrix nanocomposites: A numerical analysis

The spatial distribution of reinforcement particles has a significant effect on the mechanical response and damage evolution of metal matrix composites (MMCs). It is observed that particle clustering leads to higher flow stress, earlier particle damage, as well as lower overall failure strain. In recent years, experimental studies have shown that reducing the size of particles to the nanoscale dramatically increases the mechanical strength of MMCs even at low particle volume fractions. However, the effects of particle distribution and particle damage on the mechanical response of these metal matrix nanocomposites, which may be different from that observed in normal MMCs, has not been widely explored. In this paper, these effects are investigated numerically using plane strain discrete dislocation simulations. The results show that non-clustered random and highly clustered particle arrangements result in the highest and lowest flow stress, respectively. The effect of particle fracture on the overall response of the nanocomposite is also more significant for non-clustered random and mildly clustered particle arrangements, in which particle damage begins earlier and the fraction of damaged particles is higher, compared to regular rectangular and highly clustered arrangements.     

不锈钢冶炼渣铁浴熔融还原动力学实验研究

通过10 kg级小型不锈钢冶炼渣熔融还原试验,研究了不锈钢废渣在1 500～1 650℃温度范围内的熔融还原动力学行为,认为还原反应体现在两个阶段:反应初期不锈钢废渣熔解为反应的控速环节;而反应后期界面处的化学反应演变为反应的控速环节.从整体熔融还原试验上看,不同阶段对炉渣组成有着不同的要求:反应初期需要降低熔渣熔点,能有效促进形成液态渣,以提高不锈钢渣的熔解速度;反应后期需合理调节炉渣流动性以加速熔融还原反应.故可以通过炉渣参数优化以求在保证终渣的残铬达到较高回收的前提下尽可能提高熔融还原的速率.     

淬火温度对电弧微铸锻AerMet100钢组织与性能的影响

采用OM、XRD、SEM、TEM和力学性能试验方法,研究了在885～1150℃范围内不同淬火温度对电弧微铸锻增材制造AerMet100超高强度钢组织及力学性能的影响规律。结果表明,电弧微铸锻AerMet100钢原始态组织主要由板条马氏体和奥氏体组成,呈现出快速凝固的组织特征;随着淬火温度的升高,试验钢的凝固组织逐渐消失,当温度超过1050℃时基本上完全消除;断裂韧度随着淬火温度的升高表现出升高的趋势;抗拉强度和屈服强度随着淬火温度的升高没有明显变化;冲击吸收能量随着淬火温度的升高呈现先升高后下降的趋势,在淬火温度为1050℃时达到峰值。在试验温度范围内,1050℃左右淬火可获得优异的强韧性匹配,此时试验钢的断裂韧度为82.9 MPa·m^1/2,抗拉强度为2010 MPa,冲击吸收能量为50 J。     

电积钴板微观组织结构及力学性能对比

研究了3种电积钴板的微观组织结构和力学性能之间的差异,采用X射线衍射仪和扫描电子显微镜分析了3种电积钴板的择优取向、晶体结构和微观组织形貌;并分析了3种电积钴板的强度、硬度和韧性。结果表明：3种电积钴板均是密排六方结构（hcp）的纯钴相,晶粒取向随机。A-Co板沉积层均匀致密、孔洞较少,而B-Co板和C-Co板的沉积层较为分散且存在大量的孔洞。同时A-Co板表面的平均晶粒尺寸最小,沉积层晶粒大小分布均匀,B-Co板表面的平均晶粒尺寸最大,沉积层晶粒大小分布不均匀。3种电积钴板截面的始极片都是柱状晶结构,且始极片两侧的生长方式不同。由力学性能分析发现A-Co板的抗拉强度和硬度均高于其它2种钴板,但是韧性较差。综上所述,A-Co板的品质要明显优于B-Co板和C-Co板的品质。     

武钢热轧地下卷取机的改造

详细介绍武钢热轧厂地下卷取机的改造情况,包括侧导板、夹送辊卷筒、助卷辊等及控制系统。改造后的设备取得了较好的生产效果。     

液氨球罐应力腐蚀开裂的诊断

一台由日本工业标准JIS-SPV36钢制造、直径21.5m、容积5200m~3的大型液氨球罐,由于应力腐蚀开裂,其安全性受到严重威胁.本研究针对该球罐裂纹特征和腐蚀产物进行分析,并估算结构的可靠度;在大量现场实测和试件试验数据统计分析的基础上,提出了防止产生应力腐蚀裂纹的诊断方法,并已于1986年12月该球罐年度大修时实施.     

八碳芳烃临氢异构化反应网络的动力学研究

本文研究了一个更具普遍性的五元M~a(?)拟一级的八碳芳烃临氢异构化反应网络,并应用作者提出的试差矩阵法研究了该反应网络的双曲型动力学模型,求取了各模型参数及其表观活化能和指前因子.拟合结果与实验测定值相当吻合.     

绝热轴向固定床中气流均布的数学模型

以前文为基础,在 0.4m、0.535×0.535 m 以及1.32×1.32 m 的装置中,对侧向进、出口绝热轴向固定床反应器的气流均布问题作了进一步的研究。采用瓷球促使反应器内气流均匀分布,根据理论分析和实验结果提出了数学模型,得到气流不均匀度的表达式:s=[k_1-k_2(H/D)~(k3)][1-exp(-1/k_4Eu)]