Surface Modification of a MCFC Anode by Electrochemical Alloying

l introductionMolten carbonate fuel cell (MCFC) is believed to be one of the most promising new energy conversion device that converts chemicalenergy in fossil fuels into electricity [IM]. It isa highly efficient and environmentally cleansource of power generation. Ill MCFC technology the most frequently used anode material isporous nickel. As an anode material, the performance of porous nickel is relatively satisfactory, hilt it still needs some improvemellts, especially in its corrosion …     

Nb对镍基合金时效硬化曲线的影响

研究了Ｎｂ对燃气轮机用镍基合金时效硬化曲线的影响。结果表明，无Ｎｂ和含Ｎｂ合金均在７５０℃×１６ｈ时效达到最佳时效硬化效果。含Ｎｂ合金在所有温度下的时效硬化曲线都高于无Ｎｂ合金。Ｎｂ主要是通过使γ数量增加、γ颗粒尺寸增大、γ相成分复杂化以及使晶粒细化和晶界Ｍ２３Ｃ６呈链状分布等起到硬化作用的。但含Ｎｂ镍基合金不宜在高温下长期使用，以避免无时效硬化作用的η相析出。     

Influence of heat treatments on phase composite and mechanical properties of Ni_(47)Ti_(44)Nb_9 alloy

1　INTRODUCTIONNiTi basedshapememoryalloysarethemostimportantcommercialshapememorymaterials .InNi richNiTialloys ,some precipitatessuchasNi14 Ti11,Ni3Ti2 andNi3Ticanbeobservedduringaging[1,2 ] ,whichcanimprovethesuperelasticityofalloys[3] .Inmanycasesthealloyingorthermomechanicaltreatmentsareusedinordertochangethetempera turerangeofSMEmanifestation .TernaryadditionofniobiumtoNiTiwasreportedtosignificantlywidenthethermalhysteresisofthemartensitetransforma tion[4 ] .Asantypicalexample…     

阴极保护用铂钽复合材料的研究

研究了阴极保护用铂钽复合材料的制备、表面相结构以及在海水与淡水中的电化学性能。实验结果表明，复合金属与基体金属结合良好，电化学性能接近纯铂，是一种理想的阳极材料。     

基于Ansys的电化学加工辅助阴极设计

根据电化学加工极间间隙电势分布的拉普拉斯方程，本文提出了一种阴极设计算法：误差调整法。该算法的实现主要采用了Ansys有限元计算软件。计算结果表明：该法计算迭代次数较为适当，对于精度要求不高的电化学加工阴极设计，基于Ansys的辅助阴极设计有效可行。     

Novel technology of electroless Ni-W-P on plastics and its interface behavior

The electroless Ni-W-P coatings on polyoxymethylene(POM) were prepared. The POM was pretreated by hot spraying Al powder on it. Before the electroless Ni-W-P deposition, the POM with Al coating was flash plated in alkaline bath. The mechanism of Ni-W-P deposition was studied and the technology was optimized. The XRD analysis shows that the "as-deposited" Ni-W-P plating has mixed crystalline structure. The hardness value of deposits is more than HV700. The abrasion resistance of deposits is six times more than that of POM. Bending test was used to determine the cohesion between the deposits and the substrates. SEM was used to study the behavior of surface abrasion and interface bonding condition. The reason for the excellent cohesion was interpreted.     

铝用阴极焙烧炉设计改进及效果

新的阴极焙烧炉设计,改变传统的配置方式,充分利用有限空间扩大焙烧炉装炉能力;改变烟道连通方式,提高系统焙烧过程监控水平,控制挥发分的燃烧,有效地减少了制品的焙烧裂纹,产品合格率大幅上升;改进设计带来了增产、节能、改善工作环境、提高产品质量的良好效果。     

Ni-Ti-Nb合金不同状态下的回复应力

对在冷拔态、非真空热处理、真空热处理3种状态和不同的回复加热温度条件下Ni47Ti44Nb9合金的回复应力进行测定,分析了回复应力与温度的关系。结果表明,非真空热处理、真空热处理这两种热处理方式的最大回复应力σr^m变化不大,而冷拔态下合金的最大回复应力值σr^m远远高于其他两种状态的回复应力。     

合金元素Nb对电弧熔炼Co-Al-W合金显微组织的影响

利用光学显微镜、XRD和扫描电子显微镜等对电弧熔炼Co-8.8Al-9.8W及Co-8.8Al-9.8W-2Nb合金组织进行观察与分析,研究元素Nb对Co-Al-W合金显微组织的影响。结果表明,Co-Al-W合金的相组成主要为γ相+沉淀析出的γ’-Co3(Al,W)相。Nb的加入有利于γ’相的存在,显著提高Co-Al-W合金的硬度,且细化晶粒。     

Stability of AB5-type hydrogen storage alloys

In this paper, we deduced an empirical equation for predicting the stabilities of the hydrides of AB₅-type compounds with the consideration of the effects of geometrical factor and electric factor. The theoretical curves derived from this equation are in good agreement with the test results of La_1−xCa_xNi₅, Ml_1−xCa_xNi₅ and La_1−xCe_xNi₅ compounds. With this model, we can easily interpret the phenomenon that the initial partial substitution of R by Ca in R_1−xCa_xNi₅ (R is rare earth metal) compounds cause an increase of hydrogen desorption pressure to a maximum value, whereas in the range of larger Ca content x the hydrogen desorption pressure decreases with increasing x.     

锂离子电池正极材料LiFePO4改性研究

介绍了LiFePO4正极材料的结构特点和反应机理,详细讨论了金属离子掺杂、碳包覆和控制活性材料的尺寸等改性研究对LiFePO4材料的电化学性能的影响.从而进一步优化高性能锂离子电池正极材料的改性过程,促进锂离子电池性能的改善.     

Ni-Ti-Nb合金不同变形条件下的相变曲线

对不同的变形条件下Ni47Ti44Nb9合金的DSC相变曲线进行测定，分析了它们与变形量的变化规律。结果表明，变形量越大，相变热焓随之有所增加。     

仿生机器人运动稳定性的研究进展

对国内外仿生机器人运动稳定性的研究现状做了概括和总结,从研究模型的改进、非结构环境下稳定性判据、非线性系统下稳定性判据、多指标稳定性判据的研究等方面,阐述了其未来的研究重点和方向.     

阴极旋转电沉积生物陶瓷涂层的工艺研究

采用一种电化学沉积磷酸钙生物陶瓷涂层的新方法--阴极旋转电沉积工艺.通过测定涂层的XRD、界面结合强度、SEM观察表面与断面,研究了工艺的沉积特性及机理.在该工艺中,作为金属基体的阴极始终处于旋转状态,制备出比普通电沉积工艺更致密、均匀、尺寸更小的磷酸钙生物活性涂层,通过控制旋转速度制备出内部致密、外部多孔的梯度涂层,经后处理转化为羟基磷灰石涂层.通过控制旋转速度获得的梯度涂层,界面结合强度优于普通电沉积生物涂层.模拟体液浸泡后,在涂层表面先析出纳米粒子,之后成长为针状、网状,最后连接成一层.阴级旋转电沉积生物陶瓷梯度涂层具有较高的抗溶解性和生物活性.     

飞机液压助力器的稳定性分析

介绍了飞机液压助力器的工作原理,建立了数学模型,在此基础上并进行了相应的稳定性分析,得出了一些有益的结论。     

Effects of aging treatment on microstructure and mechanical properties of Cr25Ni35Nb and Cr35Ni45Nb furnace tube steel

Cr25Ni35Nb and Cr35Ni45Nb alloys are usually used in the ethylene cracking furnaces.However,premature failure of furnace tubes often occurs ahead of design life due to elevated temperature exposure conditions (1050-1100 ℃) and aggressive service environment.Effects of exposure temperature and time on microstructure and mechanical properties of Cr25Ni35Nb and Cr35Ni45Nb steel at aging temperature (1200 ℃) with various exposure time were simulated different service times at 1050 ℃.Change of mechanical propert...     

Nb添加对Zr_(50.5-x)Al_9Ni_(4.05)Cu_(36.45)Nb_x非晶合金热稳定性及力学性能的影响

采用铜模铸造法,制备了直径为2 mm的Zr50.5-xAl9Ni4.05Cu36.45Nbx(x=0,1,2,4,摩尔分数,%)完全非晶棒材。分别采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)、差示扫描量热计(DSC)和力学性能试验机对合金的相组成、结构、热物性参数和力学性能进行研究。结果表明:添加Nb对所研究合金的玻璃转变温度Tg影响不大,但提高了晶化温度Tx和过冷液相区ΔTx;当x=4时,合金具有最高的玻璃转变温度Tx=773.4 K和最大过冷液相区ΔTx=68.1 K。依据耐温和热塑性成形要求,非晶合金的热稳定性可用玻璃转变温度Tx和过冷液相区ΔTx来分别表示。随着合金中Nb添加量的增加,非晶合金的双重热稳定性提高。非晶合金的断裂强度随着Nb添加量的增加先减小后增加,当x=4时,合金的最高断裂强度为2032 MPa。     

不同回复加热温度对NiTiNb合金回复应力的影响

对不同回复加热温度条件下Ni47Ti44Nb9合金的回复应力进行测定,分析了其与温度的关系。结果表明,不同的回复加热温度,冷却时产生的回复应力rσm随加热温度的上升而增加。并得出在管接头等应用中,回复加热温度在200℃左右为宜。     

铝合金化学镀Ni-W-P合金耐磨性研究

研究了加热温度对铝合金(6061)化学镀Ni-V-P耐磨性的影响.400℃加热1h,Ni-V-P镀层硬度达到峰值,大约940HV100.但磨损实验发现:试样分别经200℃和400℃加热1h后,试样都产生了镀层碎裂和剥落现象.试样经600℃加热,镀层表现出良好的耐磨性,这与600℃加热1h后,镀层和基体间生成60-70μm厚的Ni-Al合金层有关.     

铸铁防锈剂乳液稳定性工艺因素的研究

为确定防锈剂配制时的工艺条件,研究了温度、乳化剂种类和浓度、油水体积比、搅拌速率、搅拌时间等参数对乳状液稳定性的影响规律,研究表明:加水的温度50℃,乳化剂浓度8%,油水体积比10∶50,搅拌速率800～1000r/min,搅拌时间8min.制得的防锈剂乳液可稳定存放45天,使铸铁件在水浸泡或模拟雨水冲淋条件下保持4天以上不生锈.