非贵金属催化电极Ni/C@CF的制备及绿色类Fenton性能

传统芬顿(Fenton)法利用Fe2+催化H_(2)O_(2)产生具有强氧化性的羟基自由基(•OH),可以高效氧化降解水中有机污染物,但其操作pH范围窄(pH≈3)和易产生铁絮凝沉淀的缺点限制了其应用发展.原子氢H*作为一种单电子供体,可以将电子快速转移到H_(2)O_(2)中,生成•OH,适用于广泛的pH值,没有铁污泥产生,是一种新型高效绿色芬顿法.然而,原子H*更易相互结合形成H_(2),极不稳定,因此,探索合适的电催化剂对H*绿色Fenton的应用起着至关重要的作用.本文以炭黑作为载体,通过液相还原法制备了具有催化活性高、性能稳定的Ni/C@碳毡(Ni/C@CF)非贵金属电催化材料,制备的Ni纳米粒子均匀分散在炭黑上.以此电极材料为阴极,构建绿色Fenton催化体系,能够催化H_(2)O和H+生成H*,进而催化H_(2)O_(2)产生•OH,高效降解去除水中抗生素污染物.通过调节制备方法、电压、溶液pH值及外加氧化剂量,确定了该体系下的最佳反应条件.

A facile preparation of 3D flower-shaped Ni/Al-LDHs covered by β-Ni(OH)2 nanoplates as superior material for high power application

In the present study,we propose a novel electrode material ofβ-nickel hydroxide covering nickel/aluminum layered double hydroxides via a facile complexation–precipitation method.The as-obtained materials with 3-dimensional nanostructures are further utilized as highly capable electrode material in nickel–metal hydride batteries.The electrochemical test results demonstrated theβ-nickel hydroxide covering nickel/aluminum-layered double hydroxides with 28%ofβ-nickel hydroxide provided a superior specific capacity value of 452 m A·h·g-1 in a current density of 5 A·g-1 using 6 M KOH as electrolyte as compared with other materials.In addition,the optimized sample displays an outstanding cyclic stability along with a huge specific capacity value of320 m Ah·g-1,and very small decay rate of 3.3%at 50 A·g-1 after 3000 cycles of charge/discharge test.These indicate that the newly designed material with nanostructures not only provides an efficient contact interface between electrolyte and active species and facilitates the transport of electrons and ions,but also protects the 3-dimensional nickel/aluminum layered double hydroxides,achieving a high specific capacity,fast redox reaction and excellent long-term cyclic stability.Therefore,theβ-nickel hydroxide covering nickel/aluminum layered double hydroxides with superior electrochemical performance is predictable to be a gifted electrode material in nickel–metal hydride batteries.

An Electronic Approach to Materials Design

A molecular orbital approach to materials design has recently made great progress. This approach is based onthe electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approachis reviewed. In particular, it is stressed that New PHACOMP approach is useful for predicting the formation oftopologically close-packed (TCP) phases (e.g., σ phase andμ phase ) in nickel based superalloys. Compared to thecurrent PHACOMP, New PHACOMP provides a better tool for designing those alloys which are free from such TCPprecipitates at service temperatures. In addition, the d-electrons concept is shown for alloy design and development.

CRACK INITIATION AND STEADY PROPAGATION OF ELASTIC-PLASTIC MATERIALS IN PLANE STRESS CONDITION

The crack tip stress-strain fields of the elastic-plastic cracked specimens have been analyzed using finite element calculations.The crack initiation and steady propagation behaviours have also been investigated by means of slip line pattern etching technique and mechanical tests. The results show that there are HRR near field and distant field in the crack tip region,and the later depends on the specimen configuration.The crack initiation behaviour is controlled by a single parameter J.In contrast,the steady crack propagation is affected by the distant strain field and can not be described by single parameter only.

Ni-Al辅助微波自蔓延烧结制备Ti_(3)SiC_(2)基金刚石复合材料工艺研究

为降低金刚石磨削工具的制造成本和能耗,探寻一种在低能耗下实现高性能陶瓷结合剂金刚石磨具的制备工艺,同时研究助燃剂Si和金刚石粒度等因素对样品物相组成、显微形貌和磨削性能的影响。采用Ti、Si、石墨粉和金刚石磨料作为原料,经冷压成型至生胚,通过Ni-Al辅助在微波场加热诱发Ti-Si-C体系发生自蔓延高温合成(SHS)反应以制备Ti_(3)SiC_(2)基金刚石复合材料。结果表明,高热值Ni-Al合金辅助可以缩短样品的烧结时间,还可以将诱发SHS反应的温度点控制在金刚石石墨化温度以下。在Ar保护气氛下,Ti-Si-C体系发生SHS反应,可生成Ti_(3)SiC_(2)、TiC和Ti5Si3等3种物相。随Si含量升高,Ti_(3)SiC_(2)相先增多后减少,当n(Ti):n(Si):n(C)=3∶1.1∶2时,复合材料的磨削性能最佳,磨耗比最高可达286.53。分析不同原料配比下的试样磨耗比差异的产生机制,认为基体组织中存在微小且分布均匀的气孔结构,在磨削时可产生大区域的平整磨削面,易于发挥金刚石磨料的磨削效果,有利于提升复合材料样品的磨削性能。

The effect of welding materials on 1Cr18Ni9Ti and 2Cr13 steel welded joints electrochemical properties

By method of TIG,two kinds of welding materials were filled in and under certain welding craft conditions,1Cr18Ni9Ti and 2Cr13 were welded.The microstructure of two kinds of welded joints were observed and analyzed by OM,SEM.Through seawater immersion test,polarization curves and AC impedance spectroscopy of two kinds of welding joints were obtained.The results show that 2Cr13 and 1Cr18Ni9Ti welded joints are typical columnar crystal,the microstructure is lath martensite+austenite+carbide.The welded joints that filled in 308 and H1Cr21Ni10Mn7Mo welding wires,corrosion resistance has same change rule:Austenite base metal>HAZ near Austenite>welded joint>HAZ near Martensite>Martensite base metal.The every zone contrast of two kinds of welded joint corrosion resistance obtains:the welded joints filled in 308>the welded joints filled in H1Cr21Ni10Mn7Mo.

Microstructure and Mechanical Properties of ZrO_2-Ni Functionally Gradient Material

The fabrication. microstructure and mechanical properties of ZrO2-Ni functionally gradient materials (FGM ) have been studied. FGM as well as non-FG M of ZrO2-Ni system was developed by powder metallurgical process. X-ray diffractometer (XRD ). electron probe microanalyzer (EPMA), scanning electron microscope (SEM ) and optical microscope were employed to investigate the crystalline phases. chemical composition and microstructure Experimental results demonstrate that the composition and microstructure of ZrO2-Ni FGM have the expected gradient distribution. There are no distinct interfaces in the FGM due to the gradient change of components. that is, the constituents are continuous in microstructure everywhere. Moreover, Vickers hardness and flexural strength were measured for the common composites as a function of composition. It is made clear that the mechanical properties of the FGM vary corresponding to the constitutional changes as well

Characteristics and electrochemical performance of cathode material Co-coated LiNiO_2 for Li-ion batteries

Spherical Ni(OH)2 powder coated with Co(OH)2 as raw material was mixed with LiOH to synthesize cathode material for lithium ion battery by using solid-state reaction. After sintered at temperature above 600 ℃, a solid solution with layer structure was formed. The result of XPS shows that it is a concentration gradient material with higher cobalt content at the surface, and the gradient decreases with increasing sintering temperature from 650 to 750 ℃. This new gradient material, called as Co-coated LiNiO2, exhibits excellent electrochemical performances for the cathode of Li-ion batteries in comparison with LiNiO2 and Co-doping LiNiO2. The discharge capacity of Co-coated LiNiO2 is over 180 mA·h/g and capacity decay per cycle is less than 0.07% when Co-coated LiNiO2 consisting of 92% nickel and 8% cobalt was sintered at the temperatures between 650-670 ℃. Though initial discharge capacity could be increased with higher sintering temperature, the cycle life would be reduced.

Degradation analysis of nickel/metal hydride battery and its electrodes materials

The results indicate that during charge and discharge, the expansion of Ni（OH）2 crystal, pulverization of MH alloy particles and falling off from current collector are identified as the main causes for deterioration of Ni/MH batteries. Meanwhile, the contact resistance of inner battery increases due to the deterioration of the negative and positive electrode, and these changes lead to increasing battery body temperature and damaging its electrode and separator. The fibre’s expansion and hole’s diminishment of battery’s separator after degradation will affect the electrochemical performance and cycle life of Ni/MH batteries.

Amorphous Zr(OH)4 coated LiNi0.915Co0.075Al0.01O2 cathode material with enhanced electrochemical performance for lithium ion batteries

LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）powders, and then characterized with scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）. Experimental results show that amorphous Zr（OH）powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50 wt% Zr（OH）coated NCA delivers a capacity of 197.6 mAh/g at the first cycle and 154.3 mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6 mAh/g at the first cycle and 142.5 mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy（EIS） results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr（OH）is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.

Comparative experiment on layered Li(Ni_(1/3)Co_(1/3)Mn_(1/3))O_2 as the alternative material for LiCoO_2

This work was financially supported by the National Natural Science Foundation of China （No.50472093）.

Preparation of New Type Ni-P Micro/Nano Metal Material Based on Bacteria Shape

A new type of Ni-P alloy with rod-shape was prepared by electroless deposition method based on the shape of Nocadia, a kind of bacteria. The material was characterized by microbiological method, scanning electron microscope, energy dispersion spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction and vibrant sample magnetometer. It was found that Ni-P alloy deposited on Nocadia surface was amorphous when pH=8.0. The amount of Ni crystalline increased with pH of plating solution. Ni-P nano-particles deposited on active locations on the surface at the initial stage, and then homogeneous Ni-P film formed with time. Nocadia remained their original rod shape after Ni-P nano-particles deposition. The new type metal material formed of Ni-P alloy with nano-particles was prepared. The mag- netization of the material prepared at pH=9.7 is greater than that prepared at pH=8.0. The magnetic loss of the material prepared at pH=9.7 is less than 0.1. The dielectric loss exceeds 0.3 when frequency is higher than 14 GHz, which is 1.5 at 18 GHz. The new type Ni-P metal material with Nocadia shape has dielectric loss property.

Hydriding and Dehydriding Characteristics of Mechanically Alloyed LaMg_(17) Ni Composite Material

A composite material with the nominal composition LaMg 17 Ni was synthesized by mechanical alloying and the hydriding/dehydriding (H/D) behaviors of this material were studied at several temperatures. This material has a hydrogen storage capacity (5.76% H 2, mass fraction) lower than conventionally alloyed La 2Mg 17 (6.63% H 2, mass fraction) without activation but shows a superior hydriding/dehydriding kinetic property. At 523 K it absorbed 4.97% (mass fraction) in less than 1 min , approximately 100 times faster than La 2Mg 17 alloy under the same conditions. This attractive kinetic property of the alloy can be ascribed to the catalytic action of Mg 2Ni, LaH 2 and La as well as the multiphase structure formed in the preparation processes. The relationships between the equilibrium plateau pressure and the temperature can be expressed as lg p eq =-2797/ T +4.267 (553 K≤ T ≤623 K) for hydriding and lg p eq =-3957/ T +6.063(553 K≤ T ≤623 K) for dehydriding.

In situ formation of multiple catalysts for enhancing the hydrogen storage of MgH_(2) by adding porous Ni_(3)ZnC_(0.7)/Ni loaded carbon nanotubes microspheres

MgH_(2) is considered one of the most promising hydrogen storage materials because of its safety,high efficiency,high hydrogen storage quantity and low cost characteristics.But some shortcomings are still existed:high operating temperature and poor hydrogen absorption dynamics,which limit its application.Porous Ni_(3)ZnC_(0.7)/Ni loaded carbon nanotubes microspheres(NZC/Ni@CNT)is prepared by facile filtration and calcination method.Then the different amount of NZC/Ni@CNT(2.5,5.0 and 7.5 wt%)is added to the MgH_(2) by ball milling.Among the three samples with different amount of NZC/Ni@CNT(2.5,5.0 and 7.5 wt%),the MgH_(2)-5 wt%NZC/Ni@CNT composite exhibits the best hydrogen storage performances.After testing,the MgH_(2)-5 wt%NZC/Ni@CNT begins to release hydrogen at around 110℃ and hydrogen absorption capacity reaches 2.34 wt%H_(2) at 80℃ within 60 min.Moreover,the composite can release about 5.36 wt%H_(2) at 300℃.In addition,hydrogen absorption and desorption activation energies of the MgH_(2)-5 wt%NZC/Ni@CNT composite are reduced to 37.28 and 84.22 KJ/mol H_(2),respectively.The in situ generated Mg_(2)NiH_(4)/Mg_(2)Ni can serve as a"hydrogen pump"that plays the main role in providing more activation sites and hydrogen diffusion channels which promotes H_(2) dissociation during hydrogen absorption process.In addition,the evenly dispersed Zn and MgZn2 in Mg and MgH_(2) could provide sites for Mg/MgH_(2) nucleation and hydrogen diffusion channel.This attempt clearly proved that the bimetallic carbide Ni_(3)ZnC_(0.7) is a effective additive for the hydrogen storage performances modification of MgH_(2),and the facile synthesis of the Ni_(3)ZnC_(0.7)/Ni@CNT can provide directions of better designing high performance carbide catalysts for improving MgH_(2).

Titanium diboride-metals gradient materials prepared by field activated diffusion bonding process

Functionally gradient samples are prepared by getting metal Ni or Cu bonded with Ni-matrix composites reinforced by TiB2 particles by field activated diffusion bonding process. The intermetallic compound of Ni3Al has been applied as a mediate layer in order to reduce residual stress. The microstracture, phase composition of the interfaces between the metal and Ni3Al are determined and the mechanical properties of the gradient materials are characterized. Elemental concentration profiles across the interfaces between layers showed significant diffusion dissolution and formation of firm bonds. Measured micro-hardness values of the sample increased monotonically from the metal substrate to the surface layer of composites. The values for the surface composite layer ranged from about 2 000 HK to 3 300 HK. The results of this investigation demonstrate the feasibility of field activated diffusion bonding process for rapid preparation of FGMs.

Synthesis and Characterization of Mg_3(PO_4)_2-coated Li_(1.05)Ni_(1/3)Mn_(1/3)Co_(1/3)O_2 Cathode Material for Li-ion Battery

Mg3（PO4）2-coated Li1.05Ni1/3Mn1/33Co1/3O2 cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, cyclic voltammetry（CV）, electrochemical impedance spectroscopy（EIS）, charge/discharge cycling and differential scanning calorimeter （DSC）. SEM analysis shows that Mg3（PO4）2-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg3（PO4）2-coating powder is homogeneous and has better layered structure than the bare one. Mg3（PO4）2-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg3（PO4）2-coated sample at 55 ℃ was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg3（PO4）2-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells： the Mg3（PO4）2 coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li1.05Ni1/3Mn1/3Co1/3O2.

Synthesis of LiCo_xNi_(1-x)O_2 cathode materials from electrolysis Co-Ni alloys

The LiCoxNi1-xO2 （x=0.2, 0.5 and 0.8） cathode materials were synthesized by sintering the mixtures of lithium salt and CoxNi1-x（OH）2 （x=0.2, 0.5 and 0.8） which were achieved from corresponding CoxNi1-x alloys by electrolysis technique. The structure and electrochemical characteristics of the obtained LiCoxNi1-xO2 were studied by XRD, SEM, PSCA and charge-discharge cycling test. The results show that the electrochemical capacities of the LiCoxNi1-xO2 （x=0.2, 0.5 and 0.8） materials are improved with the increase of the Ni content. The electrochemical performance of LiCo0.2Ni0.8O2 made in oxygen atmosphere has higher charge-discharge capacity and better cycleability compared with the one made in air atmosphere.

STRUCTURE AND PROPERTIES OF RE-Ni-B-Al_2O_3 COATING MATERIAL

The effects of heat treatment temperature on the hardness, wear resistance and structure of a coating material consisting of Ni-0.45wt% RE4.8wt% B-6.2wt% Al2O3 have been discussed. The results showed that the hachess and wear resistance of the composite material reach the optimal values when heating temperature rises to 350℃ and 500℃ respectivelg. X-ray diffraction and scanning electron microscopy indicate that the composite material is amorphous in the as-coating state. The crystallized temperature of Ni-B alloy is increased when RE and Al2O3 particles are inserted. The hardness and wear resistance of the composite are raised obviously with addition of RE and Al2O3 particles.

CHARACTERISTICS OF RE-Ni-B-Al2O3 COATING MATERIAL

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