马毅斌
,
李宁
,
黎德育
,
张密林
,
黄晓梅
腐蚀学报（英文）
用电化学方法研究了Mg-14Li-1Al-0.1Ce合金在卤素溶液(NaX, X=F, Cl,Br和I)中的腐蚀行为并用失重法测定其腐蚀速率, 用扫描电镜(SEM)观察腐蚀后的表面形貌, 利用XRD检定腐蚀产物的相组成.结果表明, 合金在卤素溶液中的腐蚀速率由低到高的顺序是:NaF<NaI<NaBr<NaCl. 经过48 h腐蚀后, 合金在NaCl、NaBr和NaI溶液中的腐蚀产物层的组分为Mg(OH)2,Li3Mg7和Li0.92Mg4.08,而在NaF溶液中的腐蚀产物层的组分为Li3Mg7和Li0.92Mg4.08. 此外, 合金在NaF溶液中的电化学活性非常低, 出现了钝化现象.电化学阻抗谱表明合金腐蚀产物层不能起到防止基体腐蚀的作用.
关键词:
镁锂合金
,
corrosion
,
sodium halide
,
EIS
,
XRD
马毅斌
,
李宁
,
黎德育
,
张密林
,
黄晓梅
腐蚀学报（英文）
用电化学方法研究了Mg-14Li-1Al-0．1Ce合金在卤素溶液（NaX，X=F，C1，Br和I）中的腐蚀行为并用失重法测定其腐蚀速率，用扫描电镜（SEM）观察腐蚀后的表面形貌，利用XRD检定腐蚀产物的相组成．结果表明，合金在卤素溶液中的腐蚀速率由低到高的顺序是：NaF〈NaI〈NaBr〈NaCl．经过48h腐蚀后，合金在NaCl、NaBr和NaI溶液中的腐蚀产物层的组分为Mg（OH）2，Li3Mg7和Li0.92Mg4.08，而在NaF溶液中的腐蚀产物层的组分为Li3Mg7和Li0．92Mg4．08．此外，合金在NaF溶液中的电化学活性非常低，出现了钝化现象．电化学阻抗谱表明合金腐蚀产物层不能起到防止基体腐蚀的作用．
关键词:
镁锂合金
,
腐蚀
,
卤化钠
,
EIS
,
XRD
冒爱琴
,
王华
,
谈玲华
,
蔺向阳
,
潘仁明
催化学报
doi:10.3724/SP.J.1088.2011.01235
对活性炭(AC)进行酸处理能够改变表面含氧官能团,从而加强金属前驱体与活性炭载体的锚固作用,改变催化剂的分散度和表面碱性.采用HCl,HNO3和HF分别对AC进行处理,制得一系列AC负载的RbNO3-KF催化剂,考察了它们在气相合成C2F5I反应中的催化性能.采用N2吸附-脱附、Boehm滴定、CO2程序升温脱附、X射线衍射、X射线光电子能谱和元素分析对催化剂进行了表征.结果表明,AC经HCl处理后RbNO3-KF/AC催化剂具有较高的分散度和适中的弱碱性,有利于气相催化合成C2F5I.各催化剂分散度大小顺序为:RbNO3-KF/AC(HNO3)＞RbNO3-KF/AC(HF)＞RbNO3-KF/AC(HCl)＞RbNO3-KF/AC.该顺序与相应载体表面的酸性和官能团变化趋势一致,但与催化剂表面的碱性并无对应关系.催化剂表面碱性与AC表面含氧官能团和表面碱性有关.
关键词:
活性炭
,
酸处理
,
表面含氧官能团
,
硝酸铷
,
氟化钾
,
五氟碘乙烷
Zhaojun LIN
,
Zhanguo WANG
,
Wei CHEN and Lanying LIN(Lab. of Sendconductor Materials Science
,
Institute of Semiconductors
,
Chinese Academy of Sciences
,
Beijing 100083
,
China)
材料科学技术（英文）
Samples have been prepared at different temperatures by loading I2 molecules into the cages of zeolite 5A, and the measurements of the absorption spectra have been carried out for the prepared samples. It is shown that I2 molecular clusters are formed in the cages of zeolite 5A,and it is also found that moIecuIar clusters which are bonded with intermoIecuIar forces have an important feature, namely, the intermolecular distance in molecular clusters can be changed on different preparing conditions and the blue shift of absorption edges can not be as the criterion of forming molecular clusters.
关键词:
Materials Research Innovations
Polycrystalline copper (I) oxide films were deposited on stainless steel substrate by galvanostatic electrodeposition method and were characterized by Xray diffraction and scanning electron microscopy. The effect of bath temperature, bath pH and current density on the compositon, grain size, surface texture and surface morphology of the electrodeposited films were investigated. The films deposited at low bath pH (less than or equal to 7) consisted of copper (I) oxide and metallic copper; while the films deposited at bath pH between 8 and 12 and bath temperature of 60 degrees C were pure copper (I) oxide. The preferred orientation of the copper (I) oxide films depended on the relative growth rate of (111) and (200) faces and could be controlled by adjusting the bath pH and/or the cathodic current density. (100)-oriented copper (1) oxide films could be deposited at pH=9 and current densities in the range of 0.25-1 mA/cm(2) while (111)-oriented films could be prepared at pH=12 or at pH=9 using the current densities between 1.5-2.5 mA/cm(2). Computer simulated crystallite shapes showed that the crystal shape changed from octahedral for (100)-oriented film to trucated pyramids and cubs for (111)-oriented film. And they were approved by scanning electron microscopy.
关键词:
copper(I) oxide;electrochemical deposition;thin films;microstructure;electrochemical synthesis;thin-films
李明洋
,
魏钦华
,
秦来顺
,
史宏声
人工晶体学报
用布里奇曼法成功制备出一种新颖的三元系碱金属卤化物闪烁晶体-KSr2I5∶Eu,加工后的晶体尺寸达15 mm×10 mm×10 mm.XRD测试结果与KSr2I5的标准卡片(卡片号为PDF#39-1140) 进行比对,结果一致.KSr2I5晶体密度为4.39 g/cm3,差示扫描量热法显示晶体的熔点约为470 ℃左右.荧光光谱和X射线激发发射光谱测试结果表明KSr2I5∶0.5%Eu晶体只有一个发射峰,位于445 nm处附近,属于典型的Eu2+的5d→4f的跃迁发射.计算表明,用PMTR1306测试KSr2I5∶0.5%Eu晶体的量子效率约为12.2%.作为一种新型的闪烁晶体具有潜在的商用化价值.
关键词:
碘化锶钾
,
闪烁晶体
,
布里奇曼法
,
碱金属卤化物
Journal of Applied Physics
Dislocation distribution near the crack tip of I and II modes in bulk aluminum single crystal has been decorated by using the etching pit technique and then was observed by scanning electron microscopy. It has been shown that two kinds of distribution of dislocations, i.e., shielding and antishielding dislocations are found to exist near the crack tip. In addition to these, the dislocation-free zone is still observed to be between the crack tip and the plastic zone. According to Rice and Thomson [Philos. Mag. 29, 73 (1974)], the dislocation mode of the elastic-plastic crack is extended to include the antishielding dislocations as part of a crack-tip equilibrium configuration, which may be described as follows: (mu-b/2-pi) (S-a-e + S-s-c + S(c)s + S(e)a) [f(x')/(x - x')]dx' + sigma-a = 0, when /x/ < C, or sigma-f, when c < /x/ < s and e < /x/ < a. The factor affecting the dislocation distribution are discussed in detail.
关键词:
electron-microscope;tem observations;plastic zone;bcc metals;fracture;ductile
Fatigue & Fracture of Engineering Materials & Structures
Nominal mode I and mixed mode I/II fatigue tests were carried out using the intermetallic compound Ni3Al(CrB) in the form of single crystal specimens. The effects of crystal orientation and load mode on fatigue crack initiation and growth were studied. The fracture surfaces of the single crystals were characterized by a cleavage-like appearance and cracking occurred either on a single {111} plane or on multiple {111} planes irrespective of whether mode I or mixed mode I/II loadings were applied. It was found that the crack initiation and growth behaviour are dependent on both crystal orientation and applied loading mode. The cracking behaviour predicted by three mixed mode fracture criteria (MTS, SED and G criteria) in polycrystalline materials under mixed mode loading can be understood from the present results on single crystals.
关键词:
fatigue cracking;mixed mode loading;crystallographic orientation;resolved shear stress;Ni3Al(CrB) single crystals;growth;alloy
杨军
,
陈鹏
,
郭芝斌
,
王垚
,
黄本生
,
朱毅科
,
李宁
功能材料
doi:10.3969/j.issn.1001-9731.2015.14.026
研究了激光焊对Fe-Mn-Si系形状记忆合金焊缝区组织和性能的影响，结果表明，激光焊焊缝区组织显著细化，大大提高基体的强度，同时，由于激光焊焊缝过冷度大，容易产生较多的层错，这些层错有利于应力诱发ε马氏体形核，从而显著提高焊缝区的形状记忆效应，和母材相比，提高幅度达40％~178％左右；在模拟油田介质情况下，激光焊焊缝耐腐蚀性能高于母材，这是因为，激光焊焊缝组织细小均匀，在腐蚀过程中产生钝化现象，同时也降低了腐蚀电池的电位差，从而降低了合金的腐蚀速度，提高耐腐蚀性能。
关键词:
激光焊
,
Fe-Mn-Si系形状记忆合金
,
焊缝区
,
形状记忆效应
,
耐腐蚀性能
