材料期刊网

由有机和无机金属前躯体自蔓延高温合成碳包覆磁纳米粒子

M.Bystrzejewski , M.Szala , W.Kiciński , W.Kaszuwara , M.H.Rummeli , T.Gemming , A.Huczko

新型炭材料 doi:10.1016/S1872-5805(09)60017-2

介绍了一项由自蔓延高温合成(SHS)碳包覆磁纳米粒子的系统研究.采用还原剂NaN3和三种不同氧化剂-聚四氟乙烯、六氯乙烷和六氯苯,实施了SHS制备.研究了金属前躯体(Fe(CO)5或K3)对产物的得率、反应热、形貌、结构和磁性能的影响.结果表明:有机铁前躯体和C2Cl6氧化剂反应体系可获得磁性最佳、得率最高的产物.

关键词: 自蔓延高温合成(SHS) , 燃烧合成 , 磁纳米粒子 , 碳纳米结构

洋葱状炭纳米粒子的无催化剂合成

M.Bystrzejewski , M.H.Rummeli , T.Gemming , H.Lange , A.Huczko

新型炭材料 doi:10.1016/S1872-5805(09)60011-1

描述了基于NaN_3-C_6Cl_6混合物热解一步合成洋葱状碳纳米粒子的方法.应用EMS, XRD, Ramans研究了缓冲气体(Ar或空气)对炭产物的得率、形貌和结构的影响.产物包含洋葱炭、非晶碳和NaCl,通过简单的纯化处理即可完全除去副产物.洋葱状炭纳米粒子的形成由热解过程中压力迅速增加产生的震动波诱导苯基活性分子合并所制.

关键词: 碳纳米洋葱 , 热解 , 气相反应 , XRD , Raman光谱

Oxygen reduction mechanism on copper in a 0.5 M H(2)SO(4)

Electrochimica Acta

The mechanism of the oxygen reduction reaction (ORR) in a naturally aerated stagnant 0.5 M H(2)SO(4) Was studied using electrochemical methods. The cathodic polarization curve showed three different regions; electrochernical impedance spectroscopy (EIS) measurement was used accordingly. The EIS data were analyzed, and the mechanism for the ORR was proposed consequently. The three regions include a limiting current density region with the main transfer of 4e(-) controlled by diffusion (-0.50V < E < -0.40V), a combined kinetic-diffusion region (-0.40V

关键词: Oxygen reduction;Hump phenomenon;Chemical redox;Copper;Electrochemical impedance spectroscopy;sulfuric-acid electrolyte;anodic-dissolution;sulfate-solutions;corrosion;behavior;adsorption;chloride;cu(111);alloy;model

Simulations of Coarsening Behavior for M23C6 Carbides in AISI H13 Steel

Xinbin HU , Mei ZHANG , Xiaochun WU , Lin LI

材料科学技术（英文）

Based on the local equilibrium assumption, coarsening behavior of M23C6 carbide at 700℃ in H13 steel was simulated by DICTRA software. The results from the calculations were compared with transmission electron microscopy (TEM) observations. The results show the interfacial energy for M23C6 in H13 steel at 700℃ is thus probably 0.7 J•m-2, which fits the experiments well. The influence of composition and temperature on the coarsening rate was also investigated by simulations. Simulations show a decrease in the coarsening rate when V/Mo ratio is increased, while the coarsening rate increases with increasing temperature.

关键词: DICTRA Simulation , 碳化物粗化 , 界面能 , H13钢

A Novel near Net-Shape Technique for P/M Parts with Large H/D Ratio

Yong LIU , Baiyun HUANG , Kechao ZHOU , Hongwu OUYANG , Yuehui HE

材料科学技术（英文）

In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of processing parameters on the microstructures and density of P/M TiAl base alloy valves were studied. Results show that the radial hot pressing is an effective technique for manufacturing valves with a H/D ratio of about 10:1, and the perfect joint interface between the Mo sheet and the parts is helpful for subsequent HIPing.

关键词: Near net-shape technique , null , null

1m3/h RO-EDI高纯水设备的研制

刘红斌 , 龚承元 , 苏建勇 , 朱孟府 , 马军 , 张西正

膜科学与技术 doi:10.3969/j.issn.1007-8924.2002.03.014

介绍了工业规模的EDI膜堆和1 m3/h RO-EDI高纯水设备的研制情况,进行了设备的稳定性试验和EDI产水的水质分析,并与离子交换树脂进行了技术经济性能比较.

关键词: 电去离子 , 反渗透 , 制药用水 , 高纯水

Copper corrosion and anodic electrodissolution mechanisms in naturally aerated stagnant 0.5 M H(2)SO(4)

Corrosion Science

Mechanisms of copper corrosion and electrodissolution in naturally aerated, stagnant 0.5 M H(2)SO(4) were investigated by means of electrochemical techniques, compared with deaerated measurements. The role of dissolved oxygen was suggested, and three models were proposed in -0.05 similar to 0.15 V vs. SCE range. Near to corrosion potential, chemical redox between cuprous intermediate and oxygen reduction reaction (ORR) intermediate accelerated copper corrosion, and corrosion rate was controlled by a combined cathodic kinetic-anodic diffusion process. in low and high potential ranges, chemical redox, occurred between cuprous intermediate and oxygen molecule, synergistically accelerated the electrodissolution of copper. (C) 2009 Elsevier Ltd. All rights reserved.

关键词: Copper;Electrochemical impedance spectroscopy (EIS);Corrosion;Electrodissolution;Chemical redox;acidic sulfate-solutions;sulfuric-acid;electrochemical reduction;impedance spectroscopy;oxygen reduction;disk-electrode;reaction;model;dissolution;behavior;iron

磁制冷材料在不同温度下的M-H曲线测量方法及设备的研究

刘金荣 , 黄焦宏 , 金培育 , 李满才 , 成永顺 , 徐来自 , 邱巨峰 , 杨保荣 , 杨文志 , 王贵 , 王正德 , 张泽玉

稀土 doi:10.3969/j.issn.1004-0277.2001.06.011

为了选择合适的磁制冷材料,得到材料的磁热效应,即ΔS-T曲线,必须测出材料在不同温度下的M-H曲线.我们采用脉冲磁场的方式提供测试所需的高磁场,自行研制了符合测试精度要求的M-H曲线测试装置,测试了金属Gd的-50℃～50℃之间的每隔10℃的不同温度下的M-H曲线.

关键词: 磁热效应 , 脉冲磁场 , 磁熵变 , M-H曲线

M2和H13钢离子渗氮-电弧镀TiAlCrN膜复合技术

陈灵 , 曾德长 , 邱万奇 , 董小虹 , 黎炳雄 , 黄拿灿

材料热处理学报

对M2和H13钢进行离子渗氮-多弧离子镀TiAlCrN膜复合表面改性,并采用电子探针、X射线衍射、扫描电镜、纳米压痕和微米划痕仪等手段分析了薄膜的成分、组织结构与力学性能.结果表明,不同衬底对膜的成分及微观结构影响不大.TiAlCrN/M2和TiAlCrN/H13复合膜的膜基结合力都比较高,而TiAlCrN/M2复合膜的综合力学性能优于TiAICrN/H13.

关键词: 离子镀 , 渗氮 , TiAlCrN涂层 , 微观结构 , 硬度

EPR investigation of local structure for Mn(H(2)O)(6) (2+) cluster in M(H(2)O)(6) XCl(6): Mn(2+) (M = Zn, Mg, Cd, Ca; X = Pt, Sn) systems at different temperatures

Chemical Physics Letters

A theoretical method for studying the inter-relation between the local structure and EPR spectra is established by diagonalizing the complete energy matrices. For [M(H(2)O)(6)]XCl(6): Mn(2+) (M = Zn, Mg, Cd, Ca; X = Pt, Sn) systems, the calculated results demonstrate that the local structures around the octahedral Mn(2+) centers in the doped systems are very similar despite of the host crystals being different. Furthermore, it is shown that the EPR zero-field parameter D depends simultaneously on the local structure parameters R and h while (a - F) depends mainly on R, whether the doped systems are at liquid-nitrogen temperature or room temperature. (C) 2008 Elsevier B.V. All rights reserved.

关键词: electron-paramagnetic-resonance;single-crystals;spectra;field;ions;spectroscopy;copper(ii);complexes;behavior;mn(ii)