固体氧化物燃料电池Ni/SDC阳极材料的制备与表征

采用一种改进的均相共沉淀法一缓冲溶液法合成出NiO-Ce0.8Sm0.2O1.9复合粉体,对其相组成和粒度进行了表征.以NiO-Ce0.8-Sm0.2O1.9复合粉体为原料制备出固体氧化物燃料电池Ni/SDC阳极材料,对其微结构和相关性能进行了测试分析,并与由机械混合NiO-SDC粉体所制备的Ni/SDC材料进行了比较.结果表明,通过缓冲溶液法合成的NiO-SDC粉体具有纳米级粒度,以其制备的Ni/SDC阳极材料比由机械混合粉体所制备Ni/SDC材料的晶粒度和孔隙更为均匀和细小,电导率也更高,且以此为阳极的SOFC单电池表现出更优异的电池性能.     

中温SOFC电池阳极NiO/Ce0.7La0.3O1.85的性能研究

以La(NO3)3、Ce(NO3)3、Ni(NO3)2和有机燃料为原料,采用低温燃烧法制备一系列不同NiO含量的NiO/Ce0.7La0.3O1.85复合阳极粉体,对制备的阳极材料的显微结构、电导性能、热膨胀性能以及电化学催化活性进行了全面的研究.结果表明具有很好的微观均匀性,较高的电催化活性.     

燃烧法制备中温SOFC电解质及其电极材料

采用一种新的燃烧合成陶瓷粉体的方法——硝酸盐-柠檬酸盐燃烧法低温合成中温SOFC所有元件的初始粉体并组装成单电池，电池的电解质材料为Ce0.8Gd0.2O1.9，阴极材料为掺杂一定量固体电解质的La0.6Sr0．4Fe0.8Co0.2O3，阳极材料为固体电解质与NiO的复合材料。单电池的性能测试结果表明：单电池的输出电压和输出电流皆随其运行温度升高而增大，同时单电池的开路电压随温度升高而下降。以Ce0.8Gd0.2O1.9电解质材料为电解质的单电池在750℃的最大输出功率密度约为85mW／cm^2。     

Ni-GDC阳极的制备及其孔隙率研究

采用缓冲溶液法制备出NiO—GDC复合粉末，该粉末压制、烧结后再经氰气气氛还原得到Ni—GDC金属陶瓷阳极。使用XRD，TEM，SEM对NiO—GDC和Ni—GDC的物相、形貌进行了观察分析，测定了阳极还原前后的相对密度、总孔隙率及开孔隙率。实验结果表明，由于NiO转变为Ni，有O的火上，使得还原后试样的相对密度明显下降，而孔隙率由15．4％提高到29．6％，且开孔隙率达到23．1％，可满足阳极作为燃料扩散通道的作用。多孔结构的Ni—GDC金属陶瓷阳檄有望成为中混固体氧化物燃料电池的阳极材料。     

IT-SOFC复合阳极材料CDC-LSCMCo的制备及性能

采用甘氨酸-硝酸盐法(GNP法)一次性合成固体氧化物燃料电池复合阳极材料Ce0.8Ca0.2O2-La0.7Sr0.3Cr0.5Mn0.5-xCoxO3-δ(CDC-LSCMCo)。XRD、SEM和EDS分析结果表明:1350℃下烧结5h能够得到单一萤石-钙钛矿结构且粒度较小(1μm左右)的复合阳极粉体。电导率的测试研究发现,温度大于750℃时,电导率随Co含量的增加而增大。800℃时,CDC-LSCMCo0.15分别在空气与氢气气氛下的电导率分别为10.5和0.7S·cm-1。SEM和XRD分析表明:CDC-LSCMCo与La0.9Sr0.1Ga0.8Mg0.2O3-δ电解质材料有很好的热与化学相容性,是一种应用前景良好的IT-SOFC阳极材料。     

燃烧法制备SOFC用Ni/YSZ阳极材料

以Y(NO3)3、Zr(NO3)4、Ni(NO3)2和有机燃料为原料,采用低温燃烧法制备了NiO/YSZ复合粉料,然后于800℃在H2中还原制备了Ni/YSZ阳极材料.研究了燃烧合成过程中氧化物与有机燃料的配比对反应产物的影响.结果表明当氧化物与燃料的比例为23时,低温燃烧后可成功合成结晶充分的NiO/YSZ粉体.对合成粉体的SEM、TEM观察以及制备的Ni/YSZ阳极材料的SEM观察结果表明,低温燃烧合成的NiO/YSZ粉体细小且两相混合均匀,颗粒粒径为0.5 μm～1 μm.与机械混合法相比,采用燃烧法合成粉体,干压成型制备的Ni/YSZ阳极材料,不仅Ni在YSZ基质中分布更均匀,而且金属陶瓷中的两相均形成了连续的网络结构.     

燃烧法制备中温SOFC电解质及其电极材料

采用一种新的燃烧合成陶瓷粉体的方法--硝酸盐-柠檬酸盐燃烧法低温合成中温SOFC所有元件的初始粉体并组装成单电池,电池的电解质材料为Ce0.8Gd0.2O1.9,阴极材料为掺杂一定量固体电解质的La0.6Sr0.4Fe0.8Co0.2O3,阳极材料为固体电解质与NiO的复合材料.单电池的性能测试结果表明:单电池的输出电压和输出电流皆随其运行温度升高而增大,同时单电池的开路电压随温度升高而下降.以Ce0.8Gd0.2O1.9电解质材料为电解质的单电池在750℃的最大输出功率密度约为85 mW/cm2.     

三层共烧制备LaCrO3基连接体/复合阳极/YsZ电解质的研究

将La_0.7Ca_0.3Cr_0.97O_3-δ（LCC）连接材料引入到NiO/YSZ阳极中,制备NiO/YSZ/LCC三相复合阳极,并进行烧结特性、微观结构、电导率、热嘭胀系数等性能对比测试.结果表明,NiO/YSZ/LCC新型复合阳极具有优良的综合性能.采用浆料浸渍法在NiO/YSZ/LCC阳极戈撑体两个表面上分别制备LCC和YSZ湿膜,1400℃空气条件下三层共烧4 h后,获得致密LCC连接体和YSZ电解质薄膜.     

乙二胺四乙酸对AZ31镁合金复合阳极氧化膜性能的影响

采用阳极氧化方法在AZ31镁合金表面制备了一种新的包含Al2O3纳米颗粒的复合阳极氧化膜,研究了添加剂乙二胺四乙酸(EDTA)对复合阳极氧化的影响。采用扫描电镜观察了复合阳极氧化膜的表面形貌及磨痕的形貌;利用涡流测厚仪测试了复合阳极氧化膜的厚度;采用极化曲线和往复摩擦磨损试验评价了复合阳极氧化膜的耐蚀性和耐磨性。结果表明,有机添加剂EDTA对阳极氧化的成膜电压、氧化膜表面形貌、厚度及其耐蚀性能均有较大影响。当EDTA浓度为0.03 mol/L时,复合阳极氧化膜表面连续致密,孔洞细小且分布均匀,耐蚀性能相对较优,且具备优异的耐磨性能。     

溶液燃烧合成制备Ni-Y2O3纳米复合粉末（英文）

采用溶液燃烧合成和氢气还原两步法制备具有超细Y2O3弥散相的Ni-Y2O3纳米复合粉末。通过DTA-TG分析探讨燃烧机理,使用场发射扫描电镜、透射电镜和X射线衍射分析技术表征燃烧得到的粉末形貌和Ni-Y2O3纳米复合粉末的形貌和物相。详细讨论原料中硝酸镍与尿素配比对燃烧得到的粉末形貌、物相和比表面积的影响。高分辨透射形貌分析结果显示合成得到的Ni-Y2O3纳米复合粉末中均匀分布的Y2O3弥散相的尺寸在10 nm左右,并且在放电等离子烧结致密化后并未明显长大。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。