甘氨酸-硝酸盐法合成高烧结活性氧化铈电解质粉体

用甘氨酸-硝酸盐法合成了适用于中低温固体氧化物燃料电池的电解质材料Ce0.8Gd0.05Y0.15O1.9,主要分析了甘氨酸/硝酸根比值对燃烧合成过程、制得粉体结构、粒度和形貌的影响,并对其烧结性能作了评价.     

甘氨酸-硝酸盐法制备NiO-Sm掺杂CeO2复合阳极粉末研究

采用甘氨酸-硝酸盐燃烧法合成了中温固体氧化物燃料电池NiO-SDC复合阳极粉末。通过XRD和扫描电子显微镜对不同甘氨酸／金属离子摩尔比合成的复合粉末的结构和形貌进行了研究。XRD结果表明，直接燃烧合成的复合粉末除了NiO和CeO2的衍射峰外，还有Ni2O3衍射峰存在，粉末经900℃煅烧2h后Ni2O3峰消失，表明形成了NiO-SDC复合阳极粉末。氢气条件下的热重分析表明，复合粉末中NiO和SDC两相比例与溶液组分配比基本一致。制备的不同NiO含量薄膜阳极的电解质支撑单电池性能测试结果表明，阳极为60％NiO-SDC的单电池具有最高的开路电压。     

Gd1-xSrxCoO3-δ系阴极材料粉体的GNP法合成及表征

采用甘氨酸-硝酸盐（GNP）法合成了GdSrCoO3-δ及Gd1-xSrxCoO3-6（x=0．1～0．5），用TG—DTA、XRD、SEM等对产物形成过程及微结构进行了表征。钙钛矿的结构随着x的增大而转变为对称性更高的晶系，当x=0．4时由正交晶系转变为立方晶系，并给出了晶系转变的XRD证据。     

La0．8Ca0．2CrO3钙钛矿复合氧化物的GNP法合成与表征

采用GNP（Glycine-Nitrate Process）法合成La0.8Ca0.2CrO3初级粉料，研究甘氨酸用量对产物的晶体结构和显微形貌的影响，并测试烧结体的相对密度和电导率。研究结果表明，甘氨酸与金属离子的摩尔比（G／M^n＋）控制在2．0～2．5时可得到颗粒尺寸细小、均匀（100nm～200nm）的单相钙钛矿粉体，烧结温度为1350℃时样品的相对密度达到91．0％，测试温度为800℃时样品的电导率达到30．5S.cm^-1。与常规固相法相比，GNP法制备的样品具有更好的烧结活性和导电性能。     

低温燃烧合成Ce0.8Nd0.2O1.9固溶体纳米粉末

采用低温燃烧合成工艺在甘氨酸-硝酸盐体系中制备出Ce0.8Nd0.2O1.9固溶体纳米粉末,重点考察了甘氨酸与硝酸盐的配比（G/N）以及焙烧温度对粉末特性的影响.通过热重-差示扫描量热分析（TG-DSC）得知,燃烧反应的点火温度为257℃.利用X射线衍射（XRD）、透射电镜（TEM）、比表面积仪（BET）及傅里叶红外光谱（FTIR）等手段对粉末的结构、形貌、成分、尺寸及比表面积进行了分析.结果表明：燃烧反应后直接得到萤石型结构的单相固溶体,晶粒尺寸为8nm-12nm之间，比表向积为38m^2/g～47m^2／g；晶粒尺寸随焙烧温度升高而增加，在800℃下焙烧1h后，可以去除反应残留物质，并使获得的品形更加完整。     

流延-共烧法制备掺杂氧化铈基阳极／电解质双层结构

采用甘氨酸／硝酸盐（GNP）法合成了具有较高烧结活性的Ce0.8Gd0.05Y0.15O1.9（GYDC）粉体，通过流延-共烧法制备了NiO—GYDC阳极／GYDC电解质双层结构。结果表明：GYDC电解质薄膜经过1400℃保温4h后可烧结致密，说明GNP法制备的GYDC粉体的烧结活性较高；通过流延．共烧法可以成功制备外观完好、平整的NiO-GYDC／GYDC双层结构，满足SOFC的组装要求。     

Gd1-xSrxCoO3-δ系阴极材料粉体的GNP法合成及表征

采用甘氨酸-硝酸盐(GNP)法合成了GdSrCoO3-δ及Gd1-xSrxCoO3-δ(x=0.1～0.5),用TG-DTA、XRD、SEM等对产物形成过程及微结构进行了表征.钙钛矿的结构随着x的增大而转变为对称性更高的晶系,当x=0.4时由正交晶系转变为立方晶系,并给出了晶系转变的XRD证据.     

低温燃烧合成Ce_(0.8)Nd_(0.2)O_(1.9)固溶体纳米粉末

采用低温燃烧合成工艺在甘氨酸-硝酸盐体系中制备出Ce0.8Nd0.2O1.9固溶体纳米粉末,重点考察了甘氨酸与硝酸盐的配比(G/N)以及焙烧温度对粉末特性的影响。通过热重-差示扫描量热分析(TG-DSC)得知,燃烧反应的点火温度为257℃。利用X射线衍射(XRD)、透射电镜(TEM)、比表面积仪(BET)及傅里叶红外光谱(FTIR)等手段对粉末的结构、形貌、成分、尺寸及比表面积进行了分析。结果表明:燃烧反应后直接得到萤石型结构的单相固溶体,晶粒尺寸为8nm~12nm之间,比表面积为38m2/g~47m2/g;晶粒尺寸随焙烧温度升高而增加,在800℃下焙烧1h后,可以去除反应残留物质,并使获得的晶形更加完整。     

熔渗法制备固体氧化燃料电池LaNi_(0.6)Fe_(0.4)O_(3-δ)基纳米复合阴极在开路条件下的铬中毒（英文）

利用甘氨酸-硝酸盐方法合成LaNi_(0.6)Fe_(0.4)O_(3-δ)(LNF)粉末,采用LNF多孔主干熔渗法制备掺杂二氧化铈LNF-钆(GDC)固体氧化燃料电池纳米复合阴极。研究了LNF-GDC纳米复合阴极的电化学性能和铬中毒行为。当甘氨酸和硝酸盐的摩尔比为1:1时可得到单相钙钛矿LNF。与LNF相比,LNF-GDC纳米复合阴极的极化阻抗显著降低,这与增强的催化活性和增大的三相边界长度有关。另外,在开路条件下,纳米复合阴极有较好的铬容限。在中温固体氧化燃料电池中,LNF-GDC纳米复合阴极有望成为一种颇具潜力的阴极材料。     

合成工艺对金刚石合成效果影响的研究

研究探讨合成工艺与金刚石合成效果的关系问题，对提高人造金刚石的品级及生产效益是有重要实际价值的。文中叙述了合成压力、温度与合成加热时问在金刚石晶体生长过程中的重要性和特性。讨论了合成工艺对金刚石合成效果的影响。提出了合成工艺是影响合成效果的重要因素。在研究中，通过对合成金刚石效果的有利因素的分析，提出了提高金刚石合成效果的合成工艺。     

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。