Fe－Mo二元合金显微组织的SEM观察EI

用扫描电镜观察分析了Ｍｏ含量为２０～５７ｗｔ％的Ｆｅ－Ｍｏ二元合金的显微组织，发现合金的相组成与相平衡图有显著差异，探讨了差异出现的原因。     

电沉积非晶态镍—钼合金及其镀层结构的研究

研究了在柠檬酸盐镀液中实现Ｎｉ，Ｍｏ共沉积的电解条件，获得了含Ｍｏ量为１６．４１％－６１．３５％（ｗｔ）的Ｎｉ－Ｍｏ合金。讨论了金属浓度比、阴极电流密度、ＰＨ值、搅拌、温度等因素对合金成分的影响，考查了所得合金的Ｘ射线衍射结构，认为沉积的Ｎｉ－Ｍｏ合金随着Ｍｏ含量的增加为Ｎｉ基取代型固溶体、过饱和固溶体、非晶态。     

电沉积非晶态镍－钼合金及其镀层结构的研究

研究了在柠檬酸盐镀液中实现Ｎｉ、Ｍｏ共沉积的电解条件，获得了合Ｍｏ量为１６．４１％～６１．３５％（Ｗｔ）的Ｎｉ－Ｍｏ合金。讨论了金属浓度比、阴极电流密度、ｐＨ值、搅拌、温度等因素对合金成分的影响，考查了所得合金的Ｘ射线衍射结构，认为电沉积的Ｎｉ－Ｍｏ合金随着Ｍｏ含量的增加为Ｎｉ基取代型固溶体、过饱和固溶体、非晶态。     

Co—Cr—Mo合金的微生物腐蚀

Ｃｏ－Ｃｒ－Ｍｏ合金是一种耐腐蚀性能很好的植入人体金属材料，在它在人体中保持钝化状态，正常情况下终身勿更换。对于从人体中取出的一支Ｃｏ－Ｃｒ－Ｍｏ合金 人关节做了失效分析，并进行了细菌对Ｃｏ－Ｃｒ－Ｍｏ合金关节试块腐蚀的模拟试验。     

Ni—Mo—P化学沉积三元合金的组织与性能研究

研究了化学沉积Ｎｉ－Ｍｏ－Ｐ三元合金的组织与性能，与Ｎｉ－Ｐ合金相比的导电相Ｍｏ元素的加入使用Ｎｉ－Ｍｏ－Ｐ合金的成份和组织发生变化，从过饱和固溶体逐渐过渡到非晶态；该合金的硬度具有和Ｎｉ－Ｐ合金同样的变化趋势，但较Ｎｉ－Ｐ合金低，抗蚀能力较强。     

Fe40Mo合金在1kPa硫蒸气中的高温硫化

用ＴＧＡ、ＸＲＤ、ＳＥＭ／ＷＤＳ对Ｆｅ４０Ｍｏ合金在１ｋＰａ及７００～９００℃的硫蒸气中的硫化动力学、产物层的组成和结构进行了分析观察。结果表明，８８０℃加炉冷热处理的样品硫化时遵从抛物线规律，１０００℃加淬火样品则可表现出线性规律。合金的硫化速度比Ｆｅ２０Ｍｏ低１～２个数量级，但仍比纯Ｍｏ快得多。发现ＭｏＳ２层可在产物层中出现，其晶体的片层取向垂直于样品表面，有利于传质。合金硫化的活化能与纯Ｍｏ的接近，表明Ｆｅ４０Ｍｏ合金在实验条件下受其中Ｍｏ的硫化控制。     

TiAl—Sb—Mo合金的高温氧化行为和机理

研究了Ｔｉ－３４Ａｌ，Ｔｉ－３４Ａｌ－０．５Ｓｂ－０．０３Ｍｏ，Ｔｉ－３４Ａｌ－１．０Ｓｂ－０．０７Ｍｏ合金在９００℃的氧化行为和机理，发现在ＴｉＡｌ基合金中复合添加Ｓｂ和Ｍｏ以后，氧化增重量增加，主要是由于Ｍｏ氧化生成易挥发的ＭｏＯ３引起的，三种合金的氧化过程都遵循氧化剥循环，残余氧化膜的平均度随合金元素添加而下降，在基体中不产生大的元素富集，添加合金元素可以促进氧化膜的种类由第一阶段向第二阶段     

Fe40Mo合金在1kPa硫蒸气中的高温硫化

用ＴＧＡ，ＸＲＤ，ＳＥＭ／ＷＤＳ对Ｆｅ４０Ｍｏ合金在１ｋＰａ及７００～９００℃的硫蒸气中的硫化动力学，产物层的组成和结构进行了分析观察，结果表明：８８０℃加炉冷热处理的样品时遵从抛物线规律，１０００℃加淬火样品则可表现出线性规律，合金的硫化速度比Ｆｅ２０Ｍｏ低１～２个数量级，但仍比纯Ｍｏ快得多，发现ＭｏＳ２层可在产生物层中出现，其晶体的片层取和垂直于样品表面，有利于传质，合金硫化的活化能与纯Ｍｏ的     

Fe20Mo合金在1kPa硫蒸汽中的高温硫化

本文用石英弹簧热重分析法测定了Ｆｅ２０Ｍｏ合金在不同温度的１ｋＰａ硫蒸汽中的硫化动力学曲线，计算了硫化速度常数，用扫描电镜观察分析了硫化产物层的结构。结果表明，加入Ｍｏ使合金的硫化速度比纯铁的降低了一个数量级，合金硫化遵从初期线性加后期抛物线的规律。温度升高使硫化加快且ＦｅＳ晶体生长趋于完善。硫化产物主要分两层，外层为ＦｅＳ，内层为富Ｍｏ的复杂硫化物且包含未完全硫化的ＦｅＭｏ金属间化合物相。应用热力学理论和以上结果探讨了合金的硫化机理     

铝粉化学镀Ni－Mo合金的析出行为

给出了铝粉化学包覆镀Ｎｉ－Ｍｏ合金工艺，并研究了镀液中Ｎｉ－Ｍｏ摩尔比及镀液温度对镀层合金成分的影响。由ＸＲＤ谱分析了镀层结构，认为是以Ｍｏ为溶质、Ｎｉ为溶剂的置换型固溶体，呈面心立方结构。在电镜下观察了镀层的表面形貌特征，解释了未能形成非晶态的原因，进一步探讨了镀层的结晶析出过程。     

Laves phase formation in solids

Structural changes of the Fe-Mo, Fe-Ti and Fe-Nb binary alloys have been investigated by means of electron microscopy and X-ray diffraction. A tweed structure representing modulation of the composition always precedes the Laves phase precipitation. The latter fact allows confirmation that the Laves phase precipitation proceeds by the spinodal mechanism. A tweed structure formation results in softening of the Fe-Ti and Fe-Nb alloys; the hardness of the Fe-Mo alloys is unchangeable.     

Development of ultra high strength steels based on spinodal decomposition

A new idea for the development of ultra high strength steels by utilizing the spinodal decomposition of the Fe-Mo binary system is proposed. The idea comprises the restraint of the brittleness of the Fe-Mo alloy by reducing the Mo-content necessary to spinodal decomposition and by microstructure refining such as grain refining, subgrain refining etc; the former is realized by the alloying with some elements which, in general, have a tendency towards ordering (i.e., negative interchange energy between the nearest neighbour atoms) when combined with iron, and the latter by thermomechanical treatment and/or cold rolling. On the basis of the idea, that hidden properties indispensable to high strength materials are successfully drawn from the Fe-Mo alloy; we have obtained a 4GPa grade high tensile steel of Fe-Mo-Co-V. This idea is sure to contribute new suggestions to the development of high strength materials.     

Bimetallic Fe-Mo sulfide/carbon nanocomposites derived from phosphomolybdic acid encapsulated MOF for efficient hydrogen generation

To tackle the energy crisis and achieve more sustainable development,hydrogen as a clean and renew-able energy resource has attracted great interest.Searching for cheap but efficient catalysts for hydrogen production from water splitting is urgently needed.In this report,bimetallic Fe-Mo sulfide/carbon nanocomposites that derived from a polyoxometalate phosphomolybdic acid encapsulated metal-organic framework MIL-100(PMA@MIL-100)have been generated and their applications in electrocatalytic hydrogen generation were explored.The PMA@MIL-100 precursor is formed via a simple one-pot hydrothermal synthesis method and the bimetallic Fe-Mo sulfide/carbon nanocomposites were obtained by chemical vapor sulfurization of PMA@MIL-100 at high temperatures.The nanocomposite samples were fully characterized by a series of techniques including X-ray diffraction,Fourier-transform infrared analysis,thermogravimetric analysis,N2 gas sorption,scanning electron microscopy,transmission elec-tron microscopy,X-ray photoelectron spectroscopy,and were further investigated as electrocatalysts for hydrogen production from water splitting.The hydrogen production activity of the best performed bimetallic Fe-Mo sulfide/carbon nanocomposite exhibits an overpotential of-0.321 V at 10 mA cm-2 and a Tafel slope of 62 mV dec-1 with a 53％reduction in overpotential compared to Mo-free counterpart composite.This dramatic improvement in catalytic performance of the Fe-Mo sulfide/carbon composite is attributed to the homogeneous distribution of the nanosized iron sulfide,MoS2 particles,and the for-mation of Fe-Mo-S phases in the S-doped porous carbon matrix.This work has demonstrated a potential approach to fabricate complex heterogeneous catalytic materials for different applications.     

Catalyst design for carbon nanotube growth using atomistic modeling

The formation and stability of bimetallic catalyst particles, in the framework of carbon nanotube growth, is studied using the Bozzolo-Ferrante-Smith (BFS) method for alloys. Monte Carlo-Metropolis simulations with the BFS method are utilized in order to predict and study equilibrium configurations for nanoscale catalyst particles which are directly relevant to the catalyst state prior to growth of carbon nanotubes. At the forefront of possible catalyst combinations is the popular Fe-Mo bimetallic catalyst, which we have recently studied experimentally. We explain our experimental results, which indicate that the growth observed is dependent on the order of co-catalyst deposition, in the straightforward interpretation of BFS strain and chemical energy contributions toward the formation of Fe-Mo catalyst prior to growth. We find that the competition between the formation of metastable inner Mo cores and clusters of surface-segregated Mo atoms in Fe-Mo catalyst particles influences catalyst formation, and we investigate the role of Mo concentration and catalyst particle size in this process. Finally, we apply the same modeling approach to other prominent bimetallic catalysts and suggest that this technique can be a powerful tool to understand and manipulate catalyst design for highly efficient carbon nanotube growth.     

非晶态Fe-Mo合金电沉积研究

从强碱性溶液体系不同含 Mo 量的溶液中以及不同电沉积工艺条件下,可以获得非晶态或晶态 Fe-Mo 合金镀层。这种镀液稳定、工艺简单,镀液中允许 Fe~(2+)离子浓度范围宽。获取非晶态Fe-Mo 合金的条件是:保持镀层中含 Mo 量在20wt-%以上。要达到此条件就必须保持镀液中的(Mo)/(Fe+Mo)×100量在66%以上,镀液温度在20—45℃范围内,Fe-Mo 合金镀层才成为非晶态。反之,当镀液温度超过55℃,镀层将转变成为晶态。     

Development of an ultra-high-strength low-alloy NiSiCrCoMo steel

An ultra-high-strength low-alloy NiSiCrCoMo steel has been developed. The development work is part of a major programme at the Defence Metallurgical Research Laboratory in the field of ultra-high-strength, high-fracture-toughness steels. In this context we undertook investigations to understand the effect of solute additions on the fracture behaviour of Armco iron and Fe-C alloys. We investigated Fe-Ni, Fe-Co, Fe-Si, Fe-Mo, Fe-C-Ni and Fe-C-Co alloys for mechanical behaviour. The report by Garrison (1986) on a Fe-C-Ni-Si-Cr alloy was an important pointer to a low-alloy, ultra-high-strength steel with high fracture toughness. The material we have now arrived at is a Fe-C-Ni-Si-Cr-Co-Mo steel with tensile, impact and fracture toughness properties matching those of maraging steel 250 grade in tonnage scale melts.     

Influence of the preparation method on the behaviour of Fe-Mo catalysts for the oxidation of methanol

A series of Fe-Mo catalysts with different properties was prepared by modification of the synthesis variables. Their catalytic behaviour in the oxidation reaction of methanol to formaldehyde was determined. The differences in their textural, morphological, chemical and structural properties were determined using nitrogen adsorption, SEM-energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, X-ray diffraction and Fourier transform-infrared analyses. We have attempted to establish relationships between these properties and their catalytic activity in the above reaction. We have found that their catalytic behaviour principally correlated with the atomic ratio of Mo Fe. This ratio was sensibly higher than that required stoichiometrically for iron(III) molybdate.     

Fe-Mo/Al_2O_3催化剂催化分解甲烷制备碳纳米管:温度对碳管结构的影响

利用化学气相沉积法,以Fe-Mo/Al_2O_3为催化剂,催化分解甲烷气体制备碳纳米管(CNTs).研究了温度,反应时间和气体流速对碳纳米管结构的影响.结果显示:温度是影响碳纳米管壁厚的关键参数.低温导致壁厚为2 nm～7 nm的多壁碳纳米管(MWCNTs)的生成.相对地,高温有利于双壁碳纳米管(DWCNTs)的生长,而更高的温度促使单壁碳纳米管(SWCNTs)的产生.进一步升高温度,得到了壁厚为3 nm～15 nm的MWCNTs和大的炭颗粒.     

Precise control of the number of walls formed during carbon nanotube growth using chemical vapor deposition

We demonstrate a one-step approach for selecting the number of walls formed during carbon nanotube (CNT) growth by catalytic decomposition of CH(4) over Fe-Mo/MgO catalysts. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA) and Raman spectroscopy analyses indicate that high purity single-walled, double-walled and triple-walled carbon nanotubes can be synthesized by tuning the Fe:Mo atomic ratio of catalysts. The results reveal that the concentration of Mo in the catalyst plays an important role in the size of catalyst particles and in the deposition rate of carbon atoms during CNT growth. Thus, the wall numbers of CNTs can be controlled precisely.     

Phase transformations in nanocrystalline alloys synthesized by mechanical alloying

The effect of nanometer grain size and extensive grain boundary regions in nanocrystalline alloy systems was investigated for the chemical order-disorder, structural, precipitation, and spinodal phase transformations. The kinetic paths for approach to the chemically ordered phase from the disordered phase in FeCo-Mo alloys were observed to be the same at different temperatures due to grain boundaries acting as short-circuited diffusion paths for atom movements. The structure of Fe₃Ge was bcc for small crystallite size and the equilibrium fcc phase developed only after a critical grain size was attained. This was understood as a manifestation of the Gibbs Thomson effect. The precipitation phase transformation in Fe-Mo alloys proceeded by a rapid movement and clustering of the Mo atoms to the grain boundaries that was correlated to the size of the nano grains, and subsequent formation of the Mo rich lambda phase directly in the grain boundary regions. The composition fluctuation domains for spinodal decomposition in nanophase Fe-Cr alloys were observed to be linearly correlated to the growth of grains.