材料期刊网

Effects of β-Dendrite Growth Velocity on β→α Transformation of Hypoperitectic Ti-46Al-7Nb Alloy

Tan He , Rui Hu , Jun Wang , Jie-Ren Yang , Jin-Shan Li

金属学报(英文版) doi:10.1007/s40195-014-0167-7

关键词:

立方 TaN纳米粉的制备

类伟巍 , 沈龙海 , 刘丹 , 李雪飞 , 彭刚 , 崔启良 , 邹广田

无机材料学报 doi:10.3724/SP.J.1077.2007.00400

采用直流电弧法使金属钽和氮气直接反应制备出了TaN纳米粉．利用XRD、XPS、TEM等测试方法对所制备的TaN纳米粉进行了表征．结果表明: 所制备的纳米粉为单一的立方相TaN, 纳米颗粒的平均粒度为5~10nm．实验中还发现氮气的气压对制备纯立方相TaN具有关键性作用, 并讨论了立方相TaN的形成机理．

关键词: 立方相TaN , nanocrystallites , dc arc discharge method

立方TaN纳米粉的制备

类伟巍 , 沈龙海 , 刘丹 , 李雪飞 , 彭刚 , 崔启良 , 邹广田

无机材料学报 doi:10.3321/j.issn:1000-324X.2007.03.004

采用直流电弧法使金属钽和氮气直接反应制备出了TaN纳米粉.利用XRD、XPS、TEM等测试方法对所制备的TaN纳米粉进行了表征.结果表明:所制备的纳米粉为单一的立方相TaN,纳米颗粒的平均粒度为5～10nm.实验中还发现氮气的气压对制备纯立方相TaN具有关键性作用,并讨论了立方相TaN的形成机理.

关键词: 立方相TaN , 纳米粉 , 直流电弧法

THERMAL NUCLEATION AND GROWTH OF He BUBBLES IN He IMPLANTED STAINLESS STEELS

ZHANG Lei WANG Peixuan TAO Rong MA Ruzhang ZHANG Guoguang University of Science and Technology Beijing , Beijing , China professor , Department of Materials Physics.University of Science and Technology Beijing.Beijing 100083 , China

金属学报(英文版)

Nucleation and growth of He bubbles at different annealing temperatures T≤1023 K in stain- less steels HR-2 and SS321,implanted with He~+(40-70 keV.1×10~(16)-6× 10~(17) He~+/cm~2),were ohserved under TEM.T=0.45T_m seems to be a transition temperature.The He bubbles continue mainly their nucleation at 0.3T_m< T<0.45T_m,and grow predominantly at T≥0.45T_m,due probably to migration and coalescence by surface diffusion of metal atoms around the bubbles.The apparent activation energies for the growth are found to he 0.41 and 0.31 eV for HR-2 and SS321 respectively.The bubble density in HR-2 is greater than that in SS321 within whole measuring temperature range,and the onset temperature of rapid swelling is also higher.It is believed that the resistance of HR-2 to He is superior to that fo SS321.

关键词: stainless steel , null , null , null , null

Microstructural study on multilayer FeTaN/TaN (5) films

Materials Letters

The microstructure of [FeTaN/TaN](5) multilayer films has been investigated by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM) in cross section and plan view. Each layer shows a small surface roughening less than 1 nm. The FeTaN layers are composed of b.c.c. Fe with Ta incorporated substitutionally and N interstitially, denoted as Fe(Ta,N); while the TaN layers mainly consist of f.c.c. TaN phase. A [110] texture of Fe(Ta,N) has been formed in the FeTaN layers. The columnar grain structure is a typical feature in FeTaN layers. (C) 2003 Elsevier Science B.V. All rights reserved.

关键词: microstructure;thin films;magnetic materials;transmission electron;microscopy (TEM);sputtering;fetan thin-films;magnetic-properties;recording-heads;tantalum;nitride;temperature

高温退火后含He纳米晶钛膜中He相关缺陷的演化

李悦 , 邓爱红 , 刘莉 , 王康 , 谢莎

材料研究学报

利用x射线衍射(xRD)和慢正电子束分析(SPBA)技术研究高温退火后含He钛膜的微观结构和钛膜内He相关缺陷的演化.XRD分析表明,高温退火后Ti和Si在高温下发生反应形成稳定的多晶TiSi2化合物,He原子的掺入会影响TiSi2晶体的择优取向,而对TiSi2晶粒尺寸的影响较小.SPBA结果表明,室温下,钛膜内的缺陷浓度或尺寸会随着掺He浓度的增加而增大;高温退火后,当He浓度小于5％(原子分数,下同)时(除2％外),钛膜内的He相关缺陷浓度随着He浓度增加相应地增加.当He浓度增加到14％时,高温会使较高浓度的He原子、He-空位复合体以及小He泡迁移聚集形成一些尺寸较大He泡,而较大He泡周围与He相关的小尺寸缺陷的浓度则会发生相应地减少.

关键词: 金属材料 , 含He钛膜 , 直流磁控溅射 , He相关缺陷 , XRD , SPBA

High temperature naphthenic acid corrosion of steel in high TAN refining media

Anti-Corrosion Methods and Materials

Purpose - This paper aims to study the corrosion behavior of carbon steel and stainless steel in white oil with naphthenic acid under high temperature. Design/methodology/approach - The weight-loss method and surface analysis were used to study the corrosion behavior of steel in white oil with naphthenic acid. Findings - Naphthenic acids corrosion rates were directly related to experimental temperature, immersion time and total acid number (TAN). The activation energy was calculated and the process kinetics could be represented by Arrhenius-type equation. The relationship between the isothermal line in liquid phase and that in vapor phase at different TAN values had a significant distinction with the change of temperature. Originality/value - The findings have important implications for assessing the corrosivity of crude oils with high TAN value from various resources.

关键词: Corrosion;Stainless steel;Oils;Acids;refineries

直流磁控溅射沉积含He钛膜的研究

施立群 , 金钦华 , 刘超卓 , 徐世林 , 周筑颖

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.045

研究了用He/Ar混合溅射气体的直流磁控溅射制备钛膜中He的掺入现象.分析结果表明,大量的He原子(He/Ti原子比高达56%) 被均匀地引入到Ti膜中,He含量可由混合溅射气体的He分量精确控制.通过调节溅射参数,可实现样品中He的低损伤引入.研究还发现,溅射沉积的含氦Ti膜具有较高的He成泡剂量和高的固He能力,这可能是溅射沉积形成了纳米晶Ti膜所致.纳米晶Ti膜较粗晶材料具有很高浓度的He捕陷中心,使He泡密度增大而泡尺寸减小.随He引入量的增加,Ti膜的晶粒尺寸减小,He引起的晶体点阵参数和X射线衍射峰宽度增大,晶体的无序程度增加.

关键词: 氦 , 损伤 , 泡 , 钛膜 , 溅射沉积

TaN薄膜局部腐蚀早期过程的ECAFM原位研究

俞春福 , 徐久军 , 黑祖昆

腐蚀与防护 doi:10.3969/j.issn.1005-748X.2004.03.005

电化学原子力显微镜(ECAFM)可以在液体环境下工作,能原位观察电极反应过程中的腐蚀界面形貌.文章介绍利用ECAFM从纳米空间分辨度上原位研究离子束增强沉积TaN膜在0.4mol/L HCl溶液中的局部腐蚀早期过程,结果发现,表面形貌为颗粒状结构的TaN膜在0.4mol/L HCl中进行阳极极化时,颗粒结构的微观顶峰优先溶解,导致颗粒高度降低,边界扩大蔓延,使膜层表面趋于平整化.

关键词: 电化学原子力显微镜 , TaN , 原位 , 腐蚀

Heuristic treatments of tricritical behaviour as observed in 4He-3He mixtures and in polymeric assemblies

Physics and Chemistry of Liquids

Tricritical behaviour in three dimensions is accessible to experiment in, for example, 4He-3He mixtures and some polymeric assemblies. Here, by largely heuristic arguments, which appeal however to some specific model Hamiltonians, we indicate how one can understand the gist of the experimental results near the tricritical point in the systems cited above. We point out that the spin fluctuations at the tricritical point are much weaker than those at the critical point, which leads to the conclusion that the tricritical behaviours can be described well by the mean-field exponents with logarithmic corrections, at d = 3.

关键词: tricritical behaviour;tricritical exponents;4He-3He mixtures;polymeric assemblies;Ising model;emery-griffiths model;single-ion-anisotropy;ising-model;phase-separation;magnetic-properties;lattice statistics;crystal-field;exponents;superconductivity;transition