材料期刊网

溅射纳米晶IN738合金涂层的抗循环氧化行为

耿树江 , 王福会 , 朱圣龙

中国腐蚀与防护学报

研究了高温合金IN738及其溅射纳米晶涂层的抗循环氧化行 为，结果表明：纳米晶涂层在950℃的抗循环氧化性能比铸态合金好,纳米晶涂层氧化时形成 双层的外氧化膜，其内层为连续的Al2O3氧化层，具有较好的保护性和粘附性，提高了 合金抗循环氧化性能.

关键词: 溅射涂层 , superalloy , nanocrystal , cyclic oxidat ion

Resistance Behaviour of Nanocrystal Nickel

Jirong SUN Yingzi ZHANG Guanghui RAO Yong LIU Shichao LIU Institute of Physics , Academia Sinica , Beijing , 100090 , China

材料科学技术（英）

The resistance behaviour of nanocrystal nickel was studied from 4 to 720 K and 0 to 20 Kbar.A linear variation of the resistance was found at low temperatures.It showed that under high temperatures, that system transformed to a more stable state,with the relaxation process taking place by stages and influenced by exerted pressures.The property,especially the stability,of nanocrystal was closely re- lated to the compacting pressure,

关键词: nanocrystal , null , null , null , null , null

Fabrication of BSCCO Nanocrystal Superconductors

Cheng ZHANG Xin WANG Yongzhong WANG Guiwen QIAO Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China

材料科学技术（英）

Nanocrystal materials have their special properties because of very small grain size.Nanocrystal superconductors were prepared by crystallizing the amorphous slices with nominal composition of Bi_(1.6)Pb_(0.4)Sr_2Ca_4Cu_5O_x at certain temperature.The measurements of R-Tcurve and x data prove all the crystallized samples have superconducting transition though their Meissner effect is weak.All the nanocrystal superconductors are mainly constituent of Bi_2Sr_2CaCu_2O_y phase by the analysis of X-ray diffraction.

关键词: nanocrystal , null , null

INFLUENCE OF NANOMETER GRAIN SIZE OF Bi-2212 PHASE ON SUPERCONDUCTIVITY

ZHANG Cheng , WANG Yongzhong , JIANG Ming , ZENG Dechang , TANG Hong , LI Zhongrun , QIAO Guiwen , CHUANG Yuzhi(Institute of Metal Research , Chinese Academy of Sciences , Shenyang , ChinaManuscript received on 20 April 1995)

金属学报(英文版)

Bi-2212 superconductive oxides with nanometer grains have been prepared by means of crystallization from amorphous materials.The structure and grain-size of samples were examined by.X-ray.diffraction,scanning electron microscopy.and high resolution electron microscopy.The temperature dependence of the resistivity.and a.c.susceptibility was measured by the standard four-probe method and the standard mutual-induction measurement,respectively.With the decrease of temperature,the resistivity of the Bi-2212 phase with grain size in nanometer was found to diminish to zero without sudden drop.No diamagnetic transition was detected from room temperature to 4.2 K.The formation of the nanocrystalline 2212 phase and the effect of grain size on the superconductivity were discussed.

关键词: :Bi-2212 , null , null , null

NANO SIZE EFFECT IN GRAIN BOUNDARY MIGRATION OF COPPER

L. Zhou , X.Q. Wei , N.G. Zhou

金属学报(英文版)

Molecular dynamics simulations of high temperature annealing of copper bicrystals have been carried out. The bicrystals have planar grain boundaries, and the gain size varies in nano range. An EAM(Embedded Atom Method) potential of FS type is used for calculating the interatomic forces. The results show that in nanocrystalline copper, GB migration driven by inter-GB reaction can take place. A critical grain size is identi¯ed, below which the inter-GB reaction becomes strong enough to trigger GB motion, which accelerates rapidly and leads to annihilation of the grain bound- aries. The critical size is found to be 16 atomic radii. A \through intermediate grain mechanism" is identi¯ed for the nano-grain boundary motion observed, which is never reported for GB migrations of conventional polycrystalline metals.

关键词: grain boundary migration , null , null

纳米晶铁酸锌和铁酸镧的合成与表征

熊纲 , 杨绪杰 , 陆路德 , 汪信

无机材料学报

用硬脂酸凝胶法制备了尖晶石型ZnFe₂O₄和钙钛矿型LaFeO₃纳米晶，通过热重差热（TG-DTA）、X射线粉末衍射（XRD）、透射电镜（TEM）和BET比表面吸附，对纳米粒子的组成、结构、形貌、粒径进行了分析和表征．

关键词: 纳米晶体 , ZnFe₂O₄ , LaFeO₃ , the stearic acid gel method

Ni—P纳米晶条带的稳定性

水嘉鹏 , 程黎放 , 刘军民 , 储照琴

金属学报

用热分析和内耗技术研究了Ni-P纳米晶的热稳定性。结果表明:在518至887K温度范围内,Ni-P纳米晶有明显的放热现象,内耗值下降,晶粒长大。表明在这个温区Ni-P纳米晶是不稳定的。

关键词: 纳米晶 , Ni-P , DSC , internal friction

铒镱共掺磷酸镧纳晶的合成和近红外荧光性质

汪琦 , 薄淑晖 , 胡晋 , 甄珍 , 刘新厚

影像科学与光化学

以磷酸三丁酯作为配体,使用高温溶液法合成了掺铒磷酸镧纳米晶体,高分辨电镜和XRD结果表明产物尺寸均一,直径4 nm左右,具有高度的结晶性,在甲苯等有机溶剂中分散性良好.近红外发光光谱表明,产物在1535 nm处有发光峰,半高全宽为50 nm,高于目前掺铒光纤放大器(EDFA)的增益带宽.通过IR、元素分析研究发现,使用真空干燥等方法不能有效去除纳晶表面的羟基.为了进一步消除表面缺陷和猝灭基团对纳晶发光性质的影响,我们尝试在其外围生长一层LaPO_4壳做成核壳粒子以消除表面缺陷和隔离猝灭基团,结果表明,新的纳晶的发光强度得到了显著提高.

关键词: 磷酸镧 , 掺铒材料 , 纳米材料 , 高温溶液法 , 近红外发光

Microstrain in Nanocrystalline Copper by High Resolution Electron Microscopy

武汉理工大学学报-材料科学版(英文版) doi:10.1007/s11595-009-4528-4

关键词:

高纯纳米晶氢氧化镁粉体制备及表征

顾惠敏 , 王伟 , 翟玉春

稀有金属材料与工程

以自制的高纯硫酸镁和由氨水、氢氧化钠组成的复合碱液为原料制备高纯纳米氢氧化镁粉体.考察几种关键因素对镁沉淀率和产物平均粒度的影响.结果表明,随着溶液中Mg~(2+)初始浓度和反应温度的提高,镁沉淀率提高,产物平均粒度先降低后提高;延长反应时间和陈化时间,镁沉淀率和产物平均粒度都提高;提高搅拌速度,镁回收率提高不大,但产物平均粒度减小.当Mg~(2+)初始浓度2.0 mol×L~(-1),反应温度50 ℃,反应时间60 min,搅拌速度900 r×min~(-1),陈化时间90 min时,Mg沉淀率为95.4 %,得到的氢氧化镁粉体为六方片状颗粒,粒度在50～140 nm,且粒度分布均匀,分散性好,纯度很高.

关键词: 氢氧化镁 , 高纯 , 纳米晶 , 氨碱沉淀法