材料期刊网

CERAMIC MATRIX COMPOSITE SYNTHESIZED BY THE PURE Al+NaOH SELF-OXIDATION

S.X.He , S.Yuan , J.Wang

金属学报(英文版)

An Al2 O3/Al ceramic matrix composite was fabricated by self-oxidation of pureAl+ NaOH,and its microstructure,mechanical properties and 9rowth mechanism wereanalyzed.Experimental results show that the composite possesses better mechanicalproperties,higher density and faster growth velocity than that made by Al-Mg-Si al-loy.The composite grows primarily along the crucible wall and has periodic wavy likestructure consisted with cell colonies.

关键词: Al2 O3/Al composite , null , null , null , null

亚稳态He(23S)原子与N2H4分子传能产物的发光研究

胡义华 , 刘美希 , 陈丽 , 王小涓 , 储焰南 , 曹德兆

量子电子学报 doi:10.3969/j.issn.1007-5461.2001.04.008

本文在流动余辉装置上,研究了亚稳态He(23S)原子与N2H4分子碰撞传能,观察到了激发态产物NH(A3II→X3∑+)、NH(c1II→a1△)、NH2(A2A1→X2B1)的发射光谱,由相对光谱强度求得了形成各产物的通道比;分析NH(A3II,v＇=0)的转动分辨谱的结果表明,v＇=0能级上的转动布居是"双模”分布,激发态产物NH(A)、NH2(A)的形成机理可能是: He(23S)+N2H4→N2H4*→NH(A)+NH2(A)+H.

关键词: 碰撞传能 , 化学发光 , NH(A3Ⅱ)的发射光谱

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

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

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

On the EPR parameters of divalent cobalt in ZnX (X = S, Se, Te) and CdTe

Zeitschrift Fur Naturforschung Section a-a Journal of Physical Sciences

The electron paramagnetic resonance (EPR) parameters g and the hyperfine structure constants A of CO2+ in ZnX (X = S, Se, Te) and CdTe are studied, using the perturbation formulas of the EPR parameters for a 3d(7) ion in tetrahedra based on two mechanism models. In these formulas, both the contributions from the conventional crystal-field (CF) mechanism and those from the charge-transfer (CT) mechanism are taken into account. According to the investigations, the sign of the g-shift DeltagCT from the CT mechanism is the same as DeltagCF from the CF mechanism, whereas the contributions to the A value from the CF and CT mechanisms have opposite signs. Particularly, the contributions to the EPR parameters from the CT mechanism increase rapidly with increase of the spin-orbit coupling coefficient of the ligand and the covalency effect of the systems, i.e. S2- < Se2- < Te2-.

关键词: crystal-fields and Spin Hamiltonians;EPR;Co2+;ZnX (X = S, Se, Te);CdTe;atomic screening constants;scf functions;field theory;cr2+ ion;spectra;znse;complexes;crystal;liyf4;znte

PbX(X=S,Se)纳米结构材料的制备方法

危兆玲 , 李天保 , 赵君芙 , 梁建 , 马淑芳 , 许并社

材料导报

PbX(X=S,Se)纳米结构材料因其良好的光电性能,在太阳能电池等方面有着较好的应用前景,目前已成为半导体领域的研究热点.概括和总结了几种制备PbX纳米材料的经典和新型方法,其中包括水热法、溶剂热法、化学气相沉积法、中孔材料模板法、熔盐籽晶法、纳米晶的取向附属物法和微波法等,并分析和讨论了各方法的特点及对应产物的特征.

关键词: PbS , PbSe , 制备方法 , 纳米结构

Theoretical investigation of the spin Hamiltonian parameters and local structure and their concentration dependences for Cd(1-x)Mn(x)S quantum dots

Physica Scripta

The spin Hamiltonian parameters (zero-field splitting D, g factors and hyperfine structure constants) and local structure as well as their concentration dependences for Cd(1-x)Mn(x)S quantum dots are theoretically investigated from the perturbation formulae of these parameters for a 3d(5) ion under trigonally distorted tetrahedra. The impurity Mn(2+) is found not to occupy exactly the host Cd(2+) site in the CdS quantum dots but to experience an inward displacement 0.041 angstrom towards the ligand triangle along the C(3)-axis because of the size mismatching substitution and the internal stress. As compared with bulk CdS : Mn(2+), the larger impurity displacement and stronger Mn(2+) 3d-3s orbital admixture in the Cd(1-x)Mn(x)S quantum dots suitably account for the higher zero-field splitting and hyperfine structure constant, respectively. The impurity axial displacement and the Mn(2+) 3d-3s orbital admixture in the Cd(1-x)Mn(x)S quantum dots may exhibit an approximately cubic increase with increasing the Mn concentration x from 0.001 to 0.15.

关键词: electron-paramagnetic-resonance;transition-metal impurities;atomic;screening constants;optical-properties;defect structures;scf;functions;crystals;ions;nanocrystals;semiconductor

Study of in-situ electrochemical SSCC/HE susceptibility probe

材料科学技术（英文）

An in-situ probe technique with an outward attached type of electrochemical sensor for inspection and evaluation of the susceptibility to sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) of pipeline/vessel was developed. The relationship between SSCC/HE susceptibility of steel UNS G10180 and UNS G11190 and I-H was determined by the measurement of the stable hydrogen permeation rate (I-H) and the study of SSCC/HE susceptibility of the above two steels in TM-01-77 solution. Environmental sensitive cracking (ESC) of UNS G10180 and UNS G11190 steels can be inspected, evaluated, judged by the combination with the microcomputer system (MCS)/periphery attachment and the designed software. The results give an important insurance for safety control of the pressurized pipeline/vessel operated in the environment with H2S.

关键词: hydrogen-induced cracking;monitoring hydrogen

Study of in-situ electrochemical SSCC/HE susceptibility probe

Xueyuan ZHANG , Enhou HAN , Yuanlong DU

材料科学技术（英文）

An in-situ probe technique with an outward attached type of electrochemical sensor for inspection and evaluation of the susceptibility to sulfide stress corrosion cracking (SSCC) and hydrogen embrittlement (HE) of pipeline/vessel was developed. The relationship between SSCC/HE susceptibility of steel UNS G10180 and UNS G11190 and I-H was determined by the measurement of the stable hydrogen permeation rate (I-H) and the study of SSCC/HE susceptibility of the above two steels in TM-01-77 solution. Environmental sensitive cracking (ESC) of UNS G10180 and UNS G11190 steels can be inspected, evaluated, judged by the combination with the microcomputer system (MCS)/periphery attachment and the designed software. The results give an important insurance for safety control of the pressurized pipeline/vessel operated in the environment with H2S.

关键词: