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1.
以偏钨酸铵和硝酸铜为原料,采用EDTA-柠檬酸法制备了含有0~0.8wt.%稀土氧化物( Ce0.8Sm0.2O1.9, SDC)的W-20Cu复合粉体,所制备的复合粉体经压制成型、1250°C烧结2h后获得SDC/W-20Cu复合材料烧结体。对所制备复合粉体进行物相、形貌的表征;研究稀土氧化物的添加对SDC/W-20Cu烧结体的密度、组织结构和物理力学性能的影响。实验结果表明:所制备的W-Cu复合粉体平均粒度为100~200nm;同时,SDC的添加对烧结体的密度和电导率会有轻微的影响,但能够抑制晶粒的长大并明显改善烧结体的力学性能。经1250°C烧结后,SDC/W-20Cu烧结体的相对密度均高于97%;当SDC的添加量为0.6%时,具有最大的抗弯强度和显微硬度,分别是1128MPa和258HV;此外,在室温和600°C的测试条件下,其最大的抗拉强度可以达到580MPa和258MPa。 相似文献
2.
Composite coatings containing Cu, Co, Ni, and samaria-doped ceria (SDC) have been fabricated using a novel hybrid atmospheric plasma spraying technique, in which a multi-component aqueous suspension of CuO, Co3O4, and NiO was injected axially simultaneously with SDC injected radially in a dry powder form. Coatings were characterized for their microstructure, permeability, porosity, and composition over a range of plasma spray conditions. Deposition efficiency of the metal oxides and SDC was also estimated. Depending on the conditions, coatings displayed either layering or high levels of mixing between the SDC and metal phases. The deposition efficiencies of both feedstock types were strongly dependent on the nozzle diameter. Plasma-sprayed metal-supported solid oxide fuel cells utilizing anodes fabricated with this technique demonstrated power densities at 0.7 V as high as 366 and 113 mW/cm2 in humidified hydrogen and methane, respectively, at 800 °C. 相似文献
3.
真空烧结制备了TiC-ZrC-Co-Ni系金属陶瓷,研究了ZrC对TiC基金属陶瓷显微组织和室温力学性能的影响。结果表明:未加ZrC的TiC基金属陶瓷的显微组织表现为经典的黑芯-灰壳组织,硬质相形状多为球形;而加入ZrC后的金属陶瓷随着ZrC加入量的增多,组织逐渐细化,硬质相形状大多数为方形,硬质相与粘结相界面呈现直线,在黑芯周围出现白色球状(Ti,Zr)C固溶体。由于Co、Ni对ZrC的润湿性不理想,金属陶瓷的致密度随着ZrC含量的增加而下降,室温力学性能(抗弯强度、硬度、断裂韧性)也随之降低。 相似文献
4.
The microstructure, mechanical properties, and micro end-milling performance of various Ti-based solid solution cermets were investigated in an attempt to understand the relationship between the raw material's properties and its tool performance. The microstructure and mechanical properties of Ti-based solid solution cermets were varied through modulation of their nitrogen and tungsten content as well as metal binder composition. The micro end-mill with a composition of (Ti0.88W0.12)C-7.5wt.%Co-7.5wt.%Ni exhibited the best performance under micro-cutting conditions. The excellent fracture toughness and reasonable hardness of this Ti-based solid solution cermets were the primary reasons for the enhanced tool performance. The overall results demonstrate that the Ti-based solid solution cermets are extremely promising for micro end-mill applications. 相似文献
5.
A porous NiO/yttria-stabilized zirconia (YSZ) anode substrate for zirconia-based tubular solid oxide fuel cells (SOFCs) was prepared by the gelcasting. The effect of the impregnation of SDC in the substrate was studied. Electrochemical impedance spectroscopy and I–V and I–P curves of the cells were measured. Scanning electron microscopy (SEM) was used to observe the microstructures. The results indicate that the performance of the cell can be significantly improved by incorporating the nano-structured SDC particles in the substrate. The peak power density of the cell is increased by about 60% and the area specific resistance (ASR) decreased by about 47% at 700 °C, compared with the unmodified cells. It is explained as the extended triple-phase boundary (TPB) in the anode substrate and the excellent electrocatalytic property of SDC. It is also found that the nano-scale SDC particles change a lot during the reduction of the anode substrate, and the morphology of the resultant SDC particles on the metal Ni is significantly different from that on the YSZ. After the long-term operation, the morphology of the SDC particles on the Ni changes again, but that on the YSZ keeps almost unchanged. 相似文献
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采用粉末冶金法制备了Ni3Al做粘结相的Ti(C,N)基金属陶瓷,研究了添加不同含量Ni3Al粘结相的金属陶瓷的力学性能和显微组织并与Ni做粘结相的金属陶瓷进行了对比。结果表明,Ni3Al作粘结相的金属陶瓷综合力学性能总体上不如Ni做粘结相的金属陶瓷,随着金属陶瓷中Ni3Al含量的增加,其洛氏硬度值不断下降,而抗弯强度和断裂韧性却不断增加;显微组织分析表明,Ni3Al做粘结相的金属陶瓷同样具有芯环结构,Ni3Al可以控制环形相的厚度,抑制晶粒异常长大,使硬质相芯相棱角圆润。Ni3Al含量为30wt%左右的金属陶瓷能够兼顾硬度和抗弯强度等力学性能,此时的主要力学性能指标为:抗弯强度1 045±80 MPa,洛氏硬度HRA89.7±0.25,断裂韧性KIC为14.26 MPa·m1/2。 相似文献
7.
采用反应合成法与粉末冶金法制备了Ag/CuO复合材料,研究了2种制备方法所获得Ag/CuO复合材料的显微组织与性能。结果表明,反应合成法制备的Ag/CuO复合材料具有独特的环状组织特点,这一特点决定了反应合成制备的Ag/CuO复合材料的机械性能和电学性能要好于粉末冶金制备的Ag/CuO复合材料。在220V交流和24V直流实验条件下,反应合成制备的Ag/CuO复合材料的电寿命是粉末冶金制备的Ag/CuO复合材料的2倍。 相似文献
8.
采用电沉积方法制备了孔隙分布均匀且沉积层从 2到 5 层的多孔Cu/Ni复合材料。研究了不同工艺参数对多孔Cu/Ni复合材料的微观结构形貌和力学性能。多孔Cu/Ni复合材料的微观结构形貌与表征参数与沉积层数密切相关,其平均孔径、孔隙率随沉积层数增加而减小,其比表面积、表观密度随沉积层数增加而增大,多孔Cu/Ni复合材料的铜层与镍层之间由于原子扩散形成固溶体合金层。材料的力学性能随沉积层数增加而提高,压缩强度可达 17.36 MPa,杨氏模量增加 7.9倍,单位体积吸能本领提高13.9倍。 相似文献
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Effects of molybdenum on the microstructure and mechanical properties of Ti(C,N)-based cermets with low Ni 总被引:7,自引:0,他引:7
WANG Saiyu XIONG Weihao YAN Mingshuang FAN Chou 《稀有金属(英文版)》2006,25(1):90-95
The effects of Mo on the microstructure and mechanical properties of Ti(C,N)-based cermets with low Ni have been studied systematically. Different contents of Mo (4-12 wt.%) were added into Tl(C,N)-based cermets. Specimens were fabricated by conventional powder metallurgy and vacuum sintered at temperatures of 1440, 1450, and 1460℃ individually. The microstructure and fracture morphology were investigated by scanning electron microscope, and the mechanical properties such as transverse strength and hardness were measured. The results show that the microstructure is uniform and the thickness of rim phase is moderate when the content of Mo is 8 wt.%; the mechanical properties of the specimens sintered at 1450℃ are better than those sintered at 1440 and 1460℃. The integrated properties of transverse strength and hardness are the best when the content of Mo is 8 wt.% and the sintering temperature is 1450℃. 相似文献
11.
D. Hathiramani R. Vaßen D. Stöver R. J. Damani 《Journal of Thermal Spray Technology》2006,15(4):593-597
Atmospheric plasma spraying (APS) is a cost-effective way to produce solid oxide fuel cell (SOFC) components. When using APS,
therefore, sinter steps can be avoided, which is essential once a metallic support is used for the SOFC. Several properties
are required regarding the microstructure of an optimized anode layer. Here, gas permeability, electrochemistry, electronic
conductivity, coefficient of thermal expansion, as well as thermal shock resistance have to be considered. Different types
of powder feedstock were investigated to develop an atmospheric plasma sprayed anode layer: (a) NiO or Ni together with YSZ
as starting materials, (b) agglomerates in which NiO and YSZ are already mixed on a submicrometer range, (c) blended NiO/YSZ
powder, and (d) separate injection of the individual NiO and YSZ powders, respectively, into the plasma by two separate powder
lines. The performance of APS anodes are measured in single fuel-cell tests. Anode layers sprayed by a separate injection
of the individual NiO and YSZ powders into the plasma show the best results.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
12.
Soumen Kar 《Journal of Alloys and Compounds》2011,509(8):3582-3586
We have reported a comprehensive study of the structural, magnetic and electrical properties of Ni (core)/NiO (shell) particles, synthesized by control oxidation of ball milled nanocrystalline (nc-) Ni particles in air. A reaction of Ni + (1/2)O2 → NiO is suspected to occur in the oxidation reaction at the temperature range of 300-800 °C. The phases of the Ni/NiO particles are composed of fcc-Ni and fcc-NiO. The phase compositions of the Ni/NiO particles change with annealing temperature. The Ni/NiO particles have a core-shell monomorphic flower-like microstructure with an average diameter of 20-80 nm. The size reduction and oxidation of the nc-Ni particles leads to a change in microstructure and thermal stability compared to bulk Ni. Thermogravimetric and differential scanning calorimetery analysis are applied to determine the thermal behavior of composites. The initial oxidation of nc-Ni particles is observed to occur around 325 °C (near Curie temperature). Anomalous magnetic and electric behavior is observed at room temperature for the nc-Ni and Ni/NiO particles. 相似文献
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研究了以流延法成型中温平板式固体氧化物燃料电池(IT-SOFC)Ni-YSZ阳极基底金属陶瓷,并成功地制备出厚度为200-500μm的该金属陶瓷基底材料.在其中添加不同种类的成孔剂以增加孔隙率.对以该流延工艺制备的素坯及复合陶瓷的性能进行了研究,其中,素坯膜的热烧结性能通过热重-差示扫描分析进行了研究;复合陶瓷基体材料的孔隙率以阿基米德排水法进行了测试;并以扫描电子显微镜观察了其微观形貌.确定了NiO-YSZ基底材料的预烧及成瓷烧结温度范围.随着烧结温度的升高,孔隙率逐渐下降.其中,有机成孔剂和无机成孔剂在造孔性能方面还存在着某些方面的差异. 相似文献
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In this study, Ni or Co + Ni bonded NbC matrix cermets with secondary carbides (Mo2C and WC) as well as Ti(C0.5N0.5) were prepared by liquid phase sintering at 1450 °C in vacuum. Detailed microstructural investigation was performed by SEM, EPMA and XRD analysis. The microstructure, mechanical properties as well as the C45 (HB140) steel turning performance of the cermets were investigated, and compared with a commercial Ti(C0.5N0.5) based cutting insert. The sintering results indicated that the partial substitution of NbC by Ti(C0.5N0.5) had a significant effect on the core-rim microstructure and refinement of NbC solution grains, as well as improved mechanical properties of the NbC-Ti(C0.5N0.5) cermets. The phase constitution and composition of the cermets were supported by thermodynamic equilibrium calculations. All sintered cermets were composed of a fcc solid solution metal binder and a cubic core-rim NbC based solution phase, as well as an independent N-rich Ti(C,N) phase. The NbC-Ti(C0.5N0.5) and Ti(C0.5N0.5) matrix cermets had a comparable HV30 of 1500–1600 kg/mm2 and a similar fracture toughness of 8.0 MPa m1/2. 相似文献
17.
采用自制的多元复式碳氮化物陶瓷粉末 ((Ti,W,Ta) (C,N) p)制备 (Ti,W,Ta) (C,N) p/Ti(C,N)基金属陶瓷。研究了 (Ti,W,Ta) (C,N) p 粉末的组织结构特征及其加入对金属陶瓷的组织及性能的影响。结果表明 ,多元复式碳氮化物粉末的晶格常数与元素的固溶度有很好的对应关系 ,调整粉末中元素的固溶度可控制粉末的晶格常数 ,进而控制材料的性能。 Ti(C,N)基金属陶瓷中 (Ti,W,Ta) (C,N) p 粉末的加入 ,有利于重金属元素 W和 Ta向粘结相中扩散 ,从而降低了硬质相在粘结相中的溶解度 ,阻碍了晶粒长大。(Ti,W,Ta) (C,N) p/Ti(C,N)基金属陶瓷各项性能指标优于 Ti(C,N)基金属陶瓷和国外对应的金属陶瓷牌号 CT5 2 5的产品。强化机制主要表现为细晶强化与固溶强化。 相似文献
18.
R. Vaßen H. Kaßner A. Stuke F. Hauler D. Hathiramani D. Stöver 《Surface & coatings technology》2008,202(18):4432-4437
Atmospheric plasma spraying technologies have been used to produce coatings for different applications in energy systems as gas turbines and solid oxide fuel cells (SOFCs). Thermal barrier coatings (TBCs) are widely used in gas turbines to protect structural parts from the combustion gases. Although they are in use since several decades there is still a large amount of research focused on a further improvement going on. Especially increased temperature capability, improved microstructures or optimized optical properties of the coatings will be described in the present paper. Atmospheric plasma spraying (APS) technology has also been used to manufacture different coatings for solid oxide fuel cell systems. These coatings include NiO/YSZ coatings for anodes, YSZ coatings for electrolytes and different functional coatings as Cr-evaporation layer on interconnects. Recent results on these different kinds of coatings will be shown. Performance data of SOFCs on metallic porous substrates will also be given. 相似文献
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以Li2CO3、NiO、Co2O3、MnO2、LiF和SiO2为原料,采用机械力活化固相法制备了Si4+和F-掺杂的锂离子电池正极材料LiNi1/3Co 1/3Mn1/3O2.通过X射线衍射(XRD)、扫描电镜(SEM)和电化学性能测试等技术研究了LiNi1/3Co1/3Mn1/3O2的结构特征、形貌及电化学性能等.结... 相似文献
20.
Mechanical properties and expansion coefficient of Mo-Cu composites with different Ni contents 总被引:2,自引:0,他引:2
Mo-Cu composites were fabricated by powder metallurgy with addition of various Ni contents.The effect of Ni contents on mechanical and thermal properties of Mo-Cu composites was investigated.The results show that mechanical and thermal properties of Mo-Cu composites are greatly affected by the addition of Ni contents.The composite powders with Ni addition exhibits high sinterability.The sintering temperature is greatly decreased and the comprehensive properties of Mo-Cu composites are obviously improved.Mo-Cu composites with a content of 1.5 wt.% Ni have relative density 99.2%,bending strength 1057.9 MPa,hardness 72.5 HRA,electronic resistivity 1.28× 10 -7Ω.m-1,thermal conductivity 139 W·m-1·K-1,and lower coefficient of thermal expansion 7.4×10-6 K 1.Mo-Cu composites have homogeneous and fine microstructure.The fracture mechanism is ductile fracture. 相似文献