材料期刊网

CVD生长多壁碳纳米管的拉曼光谱径向呼吸振动模式观察

Valeriy V. Bolotov , Vasiliy E. Kan , Egor V. Knyazev , Peter M. Korusenko , Sergey N. Nesov , Yuriy A. Sten`kin , Viktor A. Sachkov , Irina V.Ponomareva

新型炭材料 doi:10.1016/S1872-5805(15)60197-4

采用拉曼光谱仪﹑透射电镜﹑俄歇能谱仪﹑X射线光电子能谱仪等研究在SiO2/Si基底上化学沉积的多壁碳纳米管( MWCNTs)经390℃的空气中热处理120 min前后与HCl溶液化学处理前后的结构变化情况. 拉曼光谱集中测试低频(250-300 cm-1 )带. 结果表明,经热处理和化学处理后,在250-300 cm-1形成的拉曼带在峰位和半宽几乎没变. 由透射电镜可知,小直径碳纳米管的内径值与拉曼光谱测试结果一致. 这些结果表明,低频带产生于小直径碳纳米管的内壁中碳原子的径向呼吸振动.

关键词: 碳纳米管 , 径向振动模式 , 拉曼 , 化学气相沉积 , 显微镜

CARBIDES IN STEEL 4335 V

ZHONG Jiaxiang ZHENG Xiuhua XU Zongrui Beijing Institute of Technology , Beijing , ChinaBAI Dezhong Nei Monggol Machine Works No.2 , Nei Monggol , China Beijing Institute of Technology , Beijing 100081 , China

金属学报(英文版)

Three types of alloy carbides have been observed in tempered steel 4335V:M_3C,M_7C_3 and M_4C_3.The precipitation temperatures are 200—700,400 and 500 ℃ respectively.The com- position,morphologies and distribution patterns of the carbides as well as the relationship be- tween them and as-quenched substructures have been investigated.The influence of the car- bides on the low temperature impact toughness of the steel has also been discussed.

关键词: steel 4335V , null , null

The Effect of Temperature on the Electrochemical Behavior of the V(IV)/V(V) Couple on a Graphite Electrode

International Journal of Electrochemical Science

The electrochemical behavior of the V(IV)/V(V) couple in an aqueous solution of 2 mol dm(-3) H(2)SO(4)+2 mol dm(-3) VOSO(4) on a graphite electrode at different temperatures is studied by steady-state polarization and electrochemical impedance spectroscopy. The results show that the diffusion coefficient (D) of V(IV) species increases from 1.60x10(-5) to 3.15x10(-5) cm(2) s(-1) with temperature from 15 to 70 degrees C and the activation energy for diffusion of V(IV) species is 10.52 kJ mol(-1). The anodic oxidation of V(IV) is a mixed kinetic-diffusion controlled process at the anodic polarization ranged from 32 to 132 mV vs. open circuit potential (OCP). The rate constant of charge transfer for the anodic oxidation of V(IV) increases from 1.2x10(-5) to 17.7x10(-5) cm s(-1) with temperature varied from 20 to 60 degrees C, and its activation energy is 52.4 kJ mol(-1).

关键词: Vanadium redox flow battery;graphite electrode;impedance;kinetic;parameter;activation energy;redox flow battery;positive half-cell;carbon electrodes;impedance;mechanism;state

Tetragonal distortion of the tetragonal V2+-V-M center in KBr : V2+ crystal

Journal of Physics and Chemistry of Solids

The tetragonal distortion for the tetragonal V2+-V-M center in KBr:V2+ crystal is estimated by analyzing its EPR data from two theoretical models, one is the two spin-orbit (S.O.) parameter model where the contributions to EPR parameters from both the S.O. coupling of the central metal ion and that of the ligands are considered and another is the conventional one-S.O.-parameter model where only the contribution from the S.O. coupling of the central metal ion is included. The result from the two-S.O.-parameter model is more than ten times that of the one-S.O.-parameter model. The reasonableness of the former is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.

关键词: inorganic compounds;crystal fields;defects;electron paramagnetic;resonance (EPR);epr parameters;transition;ions

THERMODYNAMICS OF V REDUCTION IN SMELTING REDUCTION SLAG FOR V-Ti-CONTAINING MAGNETITE

ZHANG Binhuai LIU Qingcai LI Changwei ZOU Deyu SUN Jinbiao Chongqing University , Chongqing , China professor , Department of Metallurgy and Materials Engineering , Chongqing University , Chongqing 630044 , China

金属学报(英文版)

For slag system of CaO-SiO_2-Al_2O_3-MgO-V_2O_5,the time of V reduction to appro ch the dynamical equilibrium is about 6 h,the equilibrium time is not evidently influenced by the ratio CaO/SiO_2 and shortens with the increase of temperature.It the ratio of the weight of slag to that of iron bath is 1/2,CaO/SiO_2 0.8 and tomperature 1773 K.the maxium distribution coefficeent of V reduction is 32.4 and maxium recovery of V is 96.1%.

关键词: magnetite , null , null , null

以Ti/V/Cu、V/Cu为中间层的TiAl合金

何鹏 , 张秉刚 , 冯吉才 , 钱乙余

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2000.04.012

用真空扩散连接方法对TiAl/Ti/V/Cu/40Cr钢及TiAl/V/Cu/40Cr钢进行了研究。结果表明，以Ti/V/Cu作中间层的接头拉伸强度高于以V/Cu作中间层的接头强度。界面分析显示，Ti/V、V/Cu、Cu/40Cr钢的各个结合界面处未形成金属间化合物，而TiAl/Ti的结合界面上有Ti3Al产生；在TiAl/V的界面上有Ti3Al、Al3V两种金属间化合物产生；界面上脆性金属间化合物的产生是接头发生断裂的原因。

关键词: 扩散连接 , 界面反应 , TiAl , Ti3Al

高V钢中V(C,N)沉淀强化作用的研究

徐曼 , 孙新军 , 刘清友 , 董瀚 , 雍岐龙 , 黄金亮

钢铁钒钛 doi:10.3969/j.issn.1004-7638.2005.03.002

通过实验室轧钢试验,研究了三种高V钢轧制状态下的组织的和力学性能,并用透射电镜观察了V(C,N)析出的状况.结果表明,高V钢中可以获得单相的铁素体组织,并可以获得较高的强度,最高的屈服强度值达到525 MPa.对C3钢而言,由V(C,N)析出颗粒的沉淀强化造成的屈服强度增量最大可达244 MPa.透射电镜观察结果表明,高V钢中容易获得相间析出.试验获得的V(C,N)析出颗粒为4～10 nm,经计算分析,该尺寸在V(C,N)最大沉淀强化效果的范围.

关键词: 高V钢 , 单相铁素体组织 , 沉淀强化 , 相间析出

LATTICE PARAMETERS OF COMPLEX CARBONITRIDE CONTAINING Ti,Nb AND V

XU Wenchong SUN Fuyu Central Iron and Steel Research Institute , Ministry of Metallurgical Industry , Beijing , China XU Wenchong Senior Engineer , Dept.No.13 , Central Iron and Steel Research Institute , Ministry of Metallurgical Industry , Beijing 100081 , China

金属学报(英文版)

The lattice constants and chemical composition of Ti,Nb and V precipitates with different particle sizes have been measured hy means of CBED and EDAX.It was obtained that the concentration ratio Of Nb and V,C_(Nb)/C_V,and the lattice constants in the Nb-V steel de- crease with the decrease of the particle size of the precipitates,but there is no regularity for tattice constant of Ti,N b and V precipitate against their particle size in the Ti-V-Nb steel.

关键词: microalloyed steel , null , null

V元素对Ti-V-Cr系阻燃钛合金热强性的影响

辛社伟 , 赵永庆 , 曾卫东 , 吴欢 , 杨海瑛 , 李倩

稀有金属材料与工程

配制不同V含量的3种阻燃钛合金,分别测试其在不同热暴露和蠕变工艺下的热稳定性能和蠕变性能,并观察其显微组织.结果表明,随V元素含量的增加,合金热稳定性能和抗蠕变性能提高,并且V元素的含量对热稳定性能和蠕变性能的影响存在一个最佳含量,小于该含量时,V元素含量对热稳定性能和抗蠕变性能影响较大,大于该含量时,含量增加对其性能影响不大.在讨论中指出,V元素对热稳定性能和蠕变性能的影响主要表现在对β相稳定性的影响,对TiCr2相形成过程的影响和与空位的相互作用三个方面,并详细论述了其机理.

关键词: 阻燃钛合金 , 热稳定 , 蠕变 , 力学性能

SURFACE MODIFICATION OF V AND ITS H ABSORPTION PROPERTIES

Journal of Alloys and Compounds

Through mechanical alloying treatment of vanadium and a little LaNi5, a great number of fine particles composed of LaNi5 and a little vanadium formed on the surface of metal vanadium particles, which resulted in an improvement in the properties of the vanadium particles. For example, the modified V can be activated at room temperature, it possesses much better resistance to oxygen poisoning than unmodified metal vanadium, and after repeated H absorption-desorption cycles no severe pulverization occurred. All these characteristics are favourable for the practical application of vanadium.

关键词: hydrogen;rates;ta