材料期刊网

EFFECT OF RARE EARTH ON VANADIZATION PROCESS IN BORAX BATH

X.K. Tao , X.Cong , R.S. Peng , J.Liu and Z.Y. Liu Tianjin Institute of Technology , Tianjin 300191 , China

金属学报(英文版)

This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.

关键词: rare earth elements , null , null

CSD-La3TaO7薄膜外延生长行为

王耀 , 李成山 , 于泽铭 , 冯建情 , 金利华 , 王辉 , 张平祥

稀有金属

研究CSD技术制备La3TaO7 (LTO)缓冲层过程中前驱液的热分解行为以及热处理工艺对薄膜取向生长的影响,通过选取恰当的LTO前驱液以及快速升温热处理的方法最终获得了良好c轴织构的LTO薄膜.

关键词: 涂层导体 , 缓冲层 , 化学溶液沉积

Bi3+,Eu3+,Tb3+掺杂Lu3TaO7的发光性能研究

刘文鹏 , 张庆礼 , 杨华军 , 周鹏宇 , 孙敦陆 , 高进云 , 谷长江 , 罗建乔 , 王迪 , 殷绍唐

量子电子学报 doi:10.3969/j.issn.1007-5461.2011.02.018

采用固相反应法制备了Bi3+、Eu3+、Tb3+掺杂的Lu3TaO7.测量了样品的X射线衍射谱、激发和发射光谱及荧光衰减曲线.三种离子掺杂的Lu3TaO7均呈现出强的荧光发射,其中Bi3+具有峰位在431 nm处的一强发射宽带,衰减寿命为16.8μs,Eu3+、Tb3+则表现出稀土离子的特征锐发射峰,衰减寿命分别为1.26 ms和1.20 ms.因此,它们均是具有潜在应用前景的重闪烁体材料.

关键词: 材料 , 闪烁体 , Lu3TaO7 , 发光

Theoretical study of the superhyperfine parameters for Cu(2+) in K(2)PdX(4) (X = Cl, Br)

Hyperfine Interactions

The superhyperfine parameters T(j) (j = x, y, z) for Cu(2+) in the square-planar K(2)PdX(4) (X = Cl, Br) are theoretically studied from the perturbation formulas of these parameters for an octahedral 3d(9) cluster, by considering both the contributions from the crystal-field and charge-transfer mechanisms. The related molecular orbital coefficients are determined from the cluster approach in a uniform way. Based on one adjustable proportional factor rho for the orbital admixture coefficients, the calculated results of present work show reasonable agreement with the observed values.

关键词: Electron paramagnetic resonance (EPR);Superhyperfine interactions;Cu(2+);K(2)PdX(4) (X = Cl, Br);atomic screening constants;square-planar;angular distortions;liquid-membrane;scf functions;absorption;k2pdcl4;spectra;complexes;carrier

K60、X70管线钢奥氏体晶粒长大及再结晶的对比分析

孙震 , 张备

上海金属

通过金相观察的方法,研究了K60、X70管线钢在不同加热温度下奥氏体晶粒长大的规律及在不同变形量和变形温度下奥氏体晶粒再结晶的规律.结果表明:加热温度分别达到1 150℃和1 200℃时,K60、X70晶粒尺寸急剧增大;随着变形温度的提高,K60、X70奥氏体再结晶的临界变形量均降低;变形温度在1 150℃,变形量分别为50％和30％时,K60、X70再结晶程度可达90％以上.相比K60,X70未再结晶区狭小,为避免混晶的产生,轧制过程应尽量避开部分再结晶区.

关键词: 管线钢 , 再结晶 , 奥氏体晶粒 , 控制轧制

Investigations on the EPR Parameters for the Square Planar Cu(2+) Centers in K(2)PdX(4) (X = Cl, Br)

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The EPR parameters g factors g(parallel to), g(perpendicular to) and the hyperfine structure constants A(parallel to) and A(perpendicular to) for the square planar Cu(2+) centers in K(2)PdX(4) (X = Cl, Br) are theoretically investigated from the perturbation formulas of these parameters for a 3d(9) ion under tetragonally elongated octahedra. In these formulas, not only the contributions from the conventional crystal-field (CF) mechanism, but also those from the charge-transfer (CT) mechanism are taken into account. The related molecular orbital coefficients are uniformly determined from the cluster approach, and the tetragonal field parameters Ds and Dt are obtained from the superposition model and the local structures of the systems. Based oil only one adjustable parameter, the present results are in reasonable agreement with the observed Values. Importance of the charge-transfer contributions is more significant for ligand Br than that for Cl due to the stronger covalency and much larger spin-orbit coupling coefficient of the former.

关键词: Crystal- and ligand fields;Electron paramagnetic resonance (EPR);Cu(2+);K(2)PdX(4) (X = Cl, Br);charge-transfer transitions;atomic screening constants;liquid-membrane;scf functions;crystal;complexes;spectra;resonance;cucl42;model

K60、X80管线钢连铸坯的高温塑性

张双平 , 刘靖 , 张艳 , 张备 , 韩静涛 , 彭杰

机械工程材料

采用Gleeble 1500型热模拟试验机研究了K60、X80管线钢连铸坯在1 350～650℃、1.0×10-3 s-1应变速率下拉伸时的高温塑性.结果表明:两种钢坯的第Ⅰ脆性区间为熔点～1 300℃;在高温区1 300～900℃时两种钢的塑性均很好,没有产生明显脆化;第Ⅲ脆性区间为900～700℃,该区域可分为γ单相区和γ+α两相区两部分.

关键词: 管线钢 , 高温塑性 , γ→α相变 , 动态再结晶

Bi2Sr2CaCu2Oy单晶的变温(77～300K)X射线衍射研究

胡林生 , 孙学峰 , 赵霞 , 李晓光

低温物理学报 doi:10.3969/j.issn.1000-3258.1999.02.009

我们进行了Bi2Sr2CaCu2Oy(Bi2212)单晶变温X射线衍射(XRD)研究,定量给出温度从77K变化至300K时,c轴晶格参数和0038主峰的半高宽(FWHM)Δθ的变化.实验发现,从77K至140K,晶格参数c值变化是线性的,随温度较慢地单调增大;从140K附近至300K,c值的变化偏离了原来的线性,随温度较快地单调增大.另外,0038主峰的半高宽Δθ随温度的变化在140K附近出现一个极大值.这表明Bi2212单晶在140K附近发生了明显的反常结构变化.

关键词:

La_（0.60）Sr_（0.40-x）K_xMnO_3系列材料的磁电阻效应

赵福伟 , 唐贵德

材料科学与工程学报

利用溶胶-凝胶法（sol-gel）制备了多晶类钙钛矿型稀土锰氧化物La0.60Sr0.40-xKxMnO3（x=0.00,0.15,0.20,0.30）。发现K＋取代部分Sr2＋后,可使样品的居里温度降至室温附近,并且使样品的室温磁电阻比替代前明显增大。在1.8T的磁场下,x=0.30的样品磁电阻峰值为21%,相应的峰值温度为304K。而母体La0.60Sr0.40MnO3的磁电阻峰值仅为6.4%,峰值温度为373K。可见K＋离子替代使室温附近样品的庞磁电阻效应有了明显的改善。

关键词: 钙钛矿锰氧化物 , 磁电阻 , 溶胶-凝胶法

X70管线钢J1d和K1a与V型缺口Ak关系研究

朱杰武 , 柳永宁 , 许雁 , 冯耀荣

机械工程材料 doi:10.3969/j.issn.1000-3738.2005.06.007

在不同温度下测试了X70管线钢动态断裂韧度K1d、J1d和止裂韧度K1a以及夏氏V型缺口冲击韧度Ak,对三者的关系进行了分析.结果表明:温度和加载速率都对断裂韧度产生影响;加载速率变化引起的韧-脆断裂转变具有热激活特征,在热激活分析基础上,在应力强度因子速率K=15 MPa·m1/2s-1条件下,得出断裂韧度、止裂韧度和冲击韧度三者的关系:Ak=4.84×106T-2.8K1d(或K1a).可以用小试样Ak数据计算得到K1d和K1a.

关键词: 管线钢 , 断裂韧度 , 止裂韧度 , 韧-脆断裂转变