表面改质及强化技术

20084295等离子熔射制备梯度功能MOLB式SOFC及其复阻抗分析/杨云珍…//焊接学报.-2008,29(1):13~16采用一种融合功能梯度材料设计思想与快速原型制造等离子熔射与机器人数字化成形技术于一体的新方法,借助自主研发的梯度功能送粉系统,多层连续熔射快速制造立体结构MOLB(mono-blocklayer built)式固体氧化物燃料电池SOFC(solid oxidefuel cell)三合一电极PEN(positive electrolyte nega-tive)部件。分析了PEN部件的成分、微观组织和阳极、阴极孔隙率的连续梯度变化规律,并利用复阻抗技术对其进行导电性能测试。结果表明,采用该方法能够获得含有成分、组织呈连续梯度变化的功能涂层的SOFC核心部件PEN;与不含有梯度层的PEN相比,不仅提高电极与电解质间的匹配性,改善电极孔隙率及其分布;而且大幅度减小功能梯度PEN部件界面接触电阻,有助于提高SOFC的电性能。图5表1参1220084296等离子熔覆TiC/Ni超厚梯度熔覆层的组织与性能/曹明…//焊接学报.-2008,29(2):13~16利用等离子熔覆技术,选择适当的工艺参数...     

表面改质及强化技术

20084295等离子熔射制备梯度功能MOLB式SOFC及其复阻抗分析/杨云珍…//焊接学报.-2008,29(1):13~16采用一种融合功能梯度材料设计思想与快速原型制造等离子熔射与机器人数字化成形技术于一体的新方法,借助自主研发的梯度功能送粉系统,多层连续熔射快速制造立体结构MOLB(mono-blocklayer built)式固体氧化物燃料电池SOFC(solid oxidefuel cell)三合一电极PEN(positive electrolyte nega-tive)部件。分析了PEN部件的成分、微观组织和阳极、阴极孔隙率的连续梯度变化规律,并利用复阻抗技术对其进行导电性能测试。结果表明,采用该方法能够获得含有成分、组织呈连续梯度变化的功能涂层的SOFC核心部件PEN;与不含有梯度层的PEN相比,不仅提高电极与电解质间的匹配性,改善电极孔隙率及其分布;而且大幅度减小功能梯度PEN部件界面接触电阻,有助于提高SOFC的电性能。图5表1参1220084296等离子熔覆TiC/Ni超厚梯度熔覆层的组织与性能/曹明…//焊接学报.-2008,29(2):13~16利用等离子熔覆技术,选择适当的工艺参数...     

粉末冶金制备Al2024/SiC功能梯度复合材料的显微组织表征和力学性能（英文）

采用粉末冶金和热压技术制备了不同梯度层数和不同SiC含量的Al2024/SiC功能梯度材料。研究了梯度层数和SiC含量对Al2024/SiC功能梯度材料显微组织和力学性能的影响。XRD和SEM-EDX分析表明Al和SiC为复合材料的主要成分,同时还有Al_4C_3、CuAl_2和CuMgAl_2等其他成分。表层含有40%SiC的两层Al2024/SiC功能梯度材料具有最高的抗弯强度,为1400 MPa。显微硬度的降低和孔隙率的变化与SiC含量和金属间化合物的形成有关。结果表明,显微硬度的增加和金属间化合物的形成对复合材料力学性能的提高起重要作用。     

钛合金表面等离子体电解氮碳共渗层的特征与耐蚀性

利用等离子体电解渗技术,在TC4钛合金表面制备了等离子体电解氮碳共渗(PEN/C)层.用X射线和扫描电镜分析了渗层的成分和结构特征;用动电位极化曲线和电化学阻抗谱分析PEN/C渗层在3.5%的NaCl溶液中的电化学腐蚀行为和耐蚀性.结果表明在钛合金表面形成的PEN/C渗层为多孔状Ti(C,N),它提高了基体的腐蚀电位,增大了电荷转移电阻,减小了腐蚀电流密度.PEN/C渗层提高了钛合金基体的耐蚀性.     

一种Ti-6Al-4V功能梯度网状结构的设计与压缩性能

通过电子束选区熔化制造具有高孔隙率的多孔Ti-6Al-4V结构,旨在用于替代人类松质骨.开放的网状结构能够提供骨组织向内生长的空间,因此能更好的起到固定的作用.利用计算机辅助设计（CAD）,制备一种低密度（0.78 g/cm3）,高孔隙率（82%）,弹性模量为2.7 GPa的功能梯度网状结构.结果表明,制备的功能梯度网状结构与致密件相比,具有和松质骨接近的的弹性模量,能够有效的避免应力屏蔽效应.此外,通过增加层与层之间的厚度,可以有效的防止裂纹在网状结构中快速扩展,提高安全性.此结构的屈服强度为62 MPa,试样的组织中的细小的α’相有利于提高植入物的寿命.     

退火处理对梯度多孔Ti-6Al-4V合金组织和力学性能的影响

利用电子束逐层熔化(Additive manufacture-electron beam melting, AM-EBM)快速成型技术制备了孔隙率分层状梯度分布的Ti-6Al-4V合金,研究了退火处理对梯度多孔材料组织和力学性能的影响。结果表明,该梯度多孔材料孔壁组织为α’片层组织,片层之间有极少量的β相;其有效抗压强度、弹性模量为各均匀组分强度与模量的权重平均值。梯度多孔材料各层界面处容易产生应力不均,使其强度降低。在950_oC退火处理1h后,α相片层明显粗化,孔梁塑性提高,但有效弹性模量和抗压强度略有降低,优化了层状多孔材料的力学性质。     

成分梯度ZrN膜层的制备及摩擦学行为

采用离子镀技术在2Cr13不锈钢基体上制备了4种不同成分梯度的ZrN膜层.采用辉光放电光谱仪(GDS)考察了膜层中主要元素的分布情况,采用显微硬度仪测试了膜层的静态承载能力,在球-盘磨损试验机上考察了不同成分梯度ZrN膜层的摩擦学行为.结果表明:成分梯度过密,会使膜/基结合强度降低,静态承载能力变差;而无成分梯度,则会使膜层的脆性增大,抗疲劳性能变差;当选择3～8层且每层厚度大于0.5μm的成分梯度结构,会显著缓解膜层与基体之间应力分布的不连续性,增加膜层韧性、膜/基结合强度及静态承载能力,从而显著提高ZrN膜层的摩擦学性能.     

TiB2-Cu-Ni梯度功能材料的抗烧蚀行为

采用燃烧合成与同时致密化技术制备了TiB2-Cu-Ni5层金属-陶瓷梯度功能材料。利用扫描电镜(SEM)、电子探针(EPMA)等方法对梯度材料的成分及烧蚀前后的微观组织形貌等进行了检测，用等离子火炬电弧加热器对材料进行加热来考察梯度材料的抗热震性能以及抗烧蚀性能。结果表明，梯度功能材料各层之间的界线已经模糊，层与层之间的结合较好；梯度材料在瞬间加热时和瞬间冷却时均未出现崩裂，烧蚀后表面没有裂纹产生，说明该梯度材料具有优异的抗热震性能；烧蚀20S后，梯度功能材料烧蚀后的质量损失仅为0．5g，说明梯度功能材料具有良好的抗烧蚀性能。梯度材料的抗烧蚀机理为金属粘接剂的挥发损失、热化学烧蚀和机械冲刷。该梯度材料在固体火箭发动机的喷管、喉衬等部件上有广阔的应用前景。     

等离子喷涂梯度热障涂层的工艺优化

用正交试验方法研究了等离子喷涂工艺的4个主要参数(喷涂距离、送粉量、主气(N2)流量、喷涂电流)对梯度热障涂层的过渡层孔隙率的影响,确定了最优工艺参数,并对工艺优化后涂层的显微组织和结合强度进行研究。结果表明:在这4个工艺因素中,送粉量、喷涂距离对过渡层的孔隙率影响较大;在梯度热障涂层中,由基体到涂层表面,形成一种无宏观结合界面的成分连续变化的组织结构;工艺优化能显著提高涂层的性能,优化工艺后喷涂的梯度热障涂层结合强度达到50 MPa。     

压缩氩弧等离子束扫描对化学镀Ni-P合金镀层组织与成分的影响

用压缩氩弧等离子束快速扫描化学镀Ni-P合金镀层.组织、成分、结构和性能研究结果表明,Ni-P合金重熔层大部分为胞状枝晶组织,由Ni基固溶体、α相(铁素体)和Ni3P相组成;次层为淬火马氏体组织;基体与熔凝层之间存在梯度扩散层.     

Fabrication and electrochemical performance of solid oxide fuel cell components by atmospheric and suspension plasma spray

The theory of functionally graded material (FGM) was applied in the fabrication process of PEN (Positive-Electrolyte-Negative), the core component of solid oxide fuel cell (SOFC). To enhance its electrochemical performance, the functionally graded PEN of planar SOFC was prepared by atmospheric plasma spray (APS). The cross-sectional SEM micrograph and element energy spectrum of the resultant PEN were analyzed. Its interface resistance was also compared with that without the graded layers to investigate the electrochemical performance enhanced by the functionally graded layers. Moreover, a new process, suspension plasma spray (SPS) was applied to preparing the SOFC electrolyte. Higher densification of the coating by SPS, 1.61%, is observed, which is helpful to effectively improve its electrical conductivity. The grain size of the electrolyte coating fabricated by SPS is also smaller than that by APS, which is more favourable to obtain the dense electrolyte coatings. To sum up, all mentioned above can prove that the hybrid process of APS and SPS could be a better approach to fabricate the PEN of SOFC stacks, in which APS is for porous electrodes and SPS for dense electrolyte.     

Fabrication of Functionally Graded SOFC by APS

Atmospheric plasma spray (APS) was used to prepare the planar positive/electrolyte/negative (PEN) and mono-block layer built (MOLB) type PEN solid oxide fuel cells (SOFCs). On the basis of the spraying conditions optimized previously and the self-developed functionally graded powder feeder system, two types of PEN cells were fabricated. Then the microstructure and material composition of the PEN cells were analyzed. The results show that graded layers formed between the electrodes and electrolyte. Moreover, the material composition and the porosity of the graded layers vary gradually. In particular, the porosities of the resultant anode and cathode reach 32.74 and 32.24%, respectively. Using the AC complex impedance technique, the conductivity of the MOLB type composite electrode is tested. The electrical conductivity of the MOLB type composite electrode with the graded layers is larger than that without the graded layers. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

先进陶瓷涂层结构调控及其在固体氧化物燃料电池中的应用

等离子喷涂技术可以对陶瓷涂层的微观结构进行调控设计,因此在制备固体氧化物燃料电池方面具有独特的优势。基于等离子喷涂方法,可以直接制备或经过后处理获得致密的电解质涂层。采用等离子喷涂技术也可以制备高性能的多孔阳极和阴极,并可对钙钛矿结构阴极材料的成分和晶体结构进行调控。文中介绍了目前国内外采用涂层制备电池的方法,主要探讨了热喷涂方法制备电解质涂层的特点,对存在的问题和可行思路进行了讨论,并探讨了基于提高三相反应界面长度来制备高性能电极的方法。由于固体氧化物燃料全电池各功能层都有可能通过热喷涂方法制备,因此该方法在固体氧化物燃料电池结构设计具有巨大的潜力。     

PROPERTIES OF W/Cu FGMS CONTAINING 1%TiC OR 1%La2O3 PREPARED USING GSUHP

W / Cu functionally gradient materials (FGMs) containing 1%La_2O_3 and 1%TiC were prepared using graded sintering under ultra-high pressure (GSUHP). The specimens have been found to exhibit low porosity (11.57% and 11.35%, respectively). Shearing strength of the specimens between layers is good. Moreover, the specimens have still demonstrated good performance in testing thermal-shock resistance. When power density of laser is 200MWm~(-2), the specimens have been tested for thermal-shock resistance (1000 times); the specimens that contained 1%La_2O_3 were not subjected to damage, whereas those that contained 1%TiC began to crack. Finally, effect of additives on thermal-shock resistance was also preliminarily discussed.     

Chemical stability of glass seal interfaces in intermediate temperature solid oxide fuel cells

In intermediate temperature planar solid oxide fuel cell (SOFC) stacks, the interconnect, which is typically made from cost-effective, oxidation-resistant, high-temperature alloys, is typically sealed to the ceramic positive electrode-electrolyte-negative electrode (PEN) by a sealing glass. To maintain the structural stability and minimize the degradation of stack performance, the sealing glass has to be chemically compatible with the PEN and alloy interconnects. In the present study, the chemical compatibility of a barium-calcium-aluminosilicate (BCAS) based glass-ceramic (specifically developed as a sealant in SOFC stacks) with a number of selected oxidation resistant high temperature alloys (and the yttria-stabilized zirconia electrolyte) was evaluated. This paper reports the results of that study, with a particular focus on Crofer22 APU, a new ferritic stainless steel that was developed specifically for SOFC interconnect applications. This paper was presented at the Fuel Cells: Materials, Processing, and Manufacturing Technologies Symposium sponsored by the Energy/Utilities Industrial Sector & Ground Transportation Industrial Sector and the Specialty Materials Critical Technologies Sector at the ASM International Materials Solutions Conference, October 13–15, 2003, in Pittsburgh, PA. The symposium was organized by P. Singh, Pacific Northwest National Laboratory, S.C. Deevi, Philip Morris USA, T. Armstrong, Oak Ridge National Laboratory, and T. Dubois, U.S. Army CECOM.     

送粉激光堆焊梯度功能材料

采用同步送粉的方法进行了316L不锈钢和铁基合金粉末的激光堆焊.通过显微组织观察、SEM电镜扫描、拉伸试验、磨损试验和EDAX能谱分析等手段对激光堆焊层组织性能以及成分进行了分析和测试.两种堆焊材料的梯度功能组合使得不同堆焊部位可以满足不同的工艺和性能要求.激光堆焊层和基体呈冶金结合、稀释率小,堆焊组织细小、致密、无裂纹、气孔等缺陷,底层试样抗拉强度和伸长率达到752.4MPa和41.05%,表层材料磨损性能大大超过基体材料.送粉激光堆焊可以实现材料与性能的优化匹配,为金属零件的梯度功能修复和复杂零件的成形提供了一条有效途径.     

Microstructure and polarization resistance of thermally sprayed composite cathodes for solid oxide fuel cell use

Porous composite cathode coatings containing (La_0.8 Sr_0.2)_0.98MnO₃ (LSM) and ZrO₂-12% Y₂O₃ (YSZ) were prepared by vacuum plasma spraying (VPS) and flame spraying (FS) on prefabricated substrate-based planar solid oxide fuel cells (SOFC) with 60 mm in diameter. Microstructural observations reveal the open porosity of the cathode coatings and prove qualitatively the compositional gradient from YSZ-LSM composite to pure LSM. The electrochemical behavior was investigated by impedance spectroscopy. The results of graded cathodes compared with nongradient and bilayered ones are discussed with respect to the cathodic polarization resistance between 750 and 950°C. Bilayered cathodes indicate the lowest cathodic losses followed by the graded ones and the conventional composite. Flame spraying as a rarely used processing tool for SOFC components can provide cathodes of high electrochemical performance.     

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.     

Effects of Silver Addition on Properties and Performance of Plasma Sprayed La0.6Sr0.4Co0.2Fe0.8O3−δ Interconnect Layer

Interconnect layers on stainless steel substrates (STS430) for solid oxide fuel cells (SOFC) were built up by atmospheric plasma spraying (APS) using spray dried La_0.6Sr_0.4Co_0.2Fe_0.8O_3?δ (LSCF) and blended LSCF/Ag composites. The microstructure and phase of each coating were analyzed using scanning electron microscopy (SEM) and x-ray diffraction (XRD) studies, respectively. Furthermore, bond strength, microhardness, performance in a thermal cycle test and in an oxidation test, and electrical conductivity were measured and compared. The coatings prepared from spray dried LSCF have higher porosity and more cracks within the splats and at intersplat boundaries. In contrast, the coatings prepared from LSCF/Ag had fewer cracks and less porosity due to the relatively high ductility of silver. After oxidation testing at 800 °C for 200 h, the weight change of the STS430 substrate and the LSCF and LSCF/Ag-coated alloys were found to be 0.06833, 0.01950, and 0.01656 mg/cm², respectively. Also the electrical conductivity of LSCF and LSCF/Ag coatings were higher than that of STS430 by two orders.     

Characterization of suspension plasma-sprayed solid oxide fuel cell electrodes

Suspension plasma spray is a promising technique that uses fine particles dispersed in a liquid as feedstock material instead of dry powder as in conventional plasma spraying and has been implemented here to produce layers with appropriate morphologies and microstructures for SOFC applications.This study uses a pressurized gas delivery system to feed the slurry through a homemade two-fluid atomizing nozzle to a conventional plasma torch. The electrodes consist of porous NiO-YSZ as anode and lanthanum nickelate as cathode. The anode and respectively the cathode were deposited onto dense or porous ferritic steel substrates in order to be characterized and optimized. The cell components were examined by scanning electron microscopy (SEM), X-ray diffraction and leakage test. This paper aims at studying the influence of the suspension characteristics (surface tension and viscosity were selected as main parameters), the conditions of injection (nozzle design, gas to liquid ratio, injection angle have been identified as major parameters), the plasma conditions (plasma gas nature and flow rates, spray distance are of major importance) and finally the kinematics on the crystalline phases, the chemical composition (distribution of NiO particles into the layer), the thickness and roughness, the pore ratio and the gas permeability. Then the optimized electrodes have been deposited onto ferritic substrate to perform Open Circuit Voltage and impedance tests at a temperature around 800 °C. This work demonstrated the feasibility for the fabrication of electrodes with interesting performance using suspension plasma spraying technique.