S.R. Lee
,
E.S.Byon and Y.-W. Seo 1)Korea Institnte of Machinery and Materials
,
Changwon 641-010
,
Korea 2)V & P International Co.
,
Ltd
,
705-9
,
Gozandong
,
Inchon 405-310
,
Korea Manuscript received 26 August 1996)
金属学报(英文版)
Cubic boron nitride (c-BN) films were successfully grown on Si(100)substrates by a helicon wave plasma-assisted chemical vapor deposition technique.The lower limits of rf substrated bias voltage and plasma density for formation of a single phase c-BN film were 350V and 4.5×10~(10) cm~(3),respectively. The grown c-BN films demonstrated a poor adhesion to the substrates. A postannealing treatment at 800℃ C in N_2 atmosphere was found very effective in relieving the compressive stress in the films which were thereby stabilized to improve the adhesion.
关键词:
:cubic boron nitride
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null
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null
,
null
杨志南
,
刘峰超
,
闫志刚
,
张福成
稀有金属材料与工程
主要研究了热轧和冷轧后Zr705合金在200～850℃温度范围内的退火行为.与冷轧后Zr705相比,热轧Zr705试样在较高的温度获得峰值硬度,且峰值硬度值较低.通过微观组织观察发现,热轧后Zr705试样中的β相向ω相的转变速率低于冷轧Zr705试样.经500℃退火后冷轧和热轧试样中均可观察到部分再结晶晶粒,但在热轧Zr705试样中的再结晶晶粒更多.热轧和冷轧Zr705试样在700℃保温1h后均再结晶完全.
关键词:
锆合金
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退火
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组织
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硬度
朱日彰
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郑晓光
中国腐蚀与防护学报
<正> 燃气涡轮高温台金部件在600～850℃之间由熔盐引起的加速腐蚀(低温热腐蚀)现象,是当前热腐蚀研究中的一个重要问题,一般舰船及一些工业涡轮的热腐蚀多属此类。 关于镍基合金的加速腐蚀机制,目前已有许多研究,但尚未获得很好的解释。本工作对纯镍在705℃几种不同条件下的熔盐腐蚀行为进行了研究,并对镍的加速腐蚀机制进行了探讨。
关键词:
屈凤波
,
杨振强
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樊燕鸽
,
陈辉
,
杨瑞娜
合成材料老化与应用
以溴苯为起始原料,经过格氏反应,偶联反应,加成反应,酸催化闭环合成了2-溴-9,9'-螺二芴,最后与二苯基膦锂锂化反应合成目标化合物二苯基-2-(9,9'-螺二芴基)膦,总收率为60.6％.通过1H NMR确证了目标化合物的结构.
关键词:
二苯基-2-(9,9'-螺二芴基)膦
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2-溴-9,9'-螺二芴
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合成与表征
Nunghee RYU
,
Sunggoon KANG
材料科学技术（英文）
The effects of laser hardening parameters such as beam power, beam diameter and scanning rate on microstructure and hardness of 9CrSi steel were investigated. The microstructure of the surface layer of 9CrSi steel was changed from pearlite to martensite, retained austenite and carbide by laser hardening. The depth of the hardened layer increased with increasing laser energy density and the surface hardeness increased by 3~5 times as high as the untreated steel. The laser hardened surface had good wear resistance due to martensite and carbide in the surface layer. The wear mode at low speed was abrasive, while the wear mode at high speed was adhesive.
关键词:
Laser hardening
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null
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null
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null
李建丰
,
常文利
,
陶春兰
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欧谷平
,
张福甲
功能材料
详细叙述了利用9-溴蒽为原料制备高纯9,9'-联二蒽的方法,通过红外光谱、核磁共振谱、质谱对其结构进行了表征,并通过X射线衍射谱和紫外-可见光光谱分析了其成膜结晶性能和光吸收特性.
关键词:
有机半导体材料
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9,9′-联二蒽
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合成
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结构表征
李建丰
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常文利
,
张春林
,
张福甲
功能材料
利用常规的真空蒸发技术,在热氧化硅片的衬底上制备了不同的衬底温度、蒸发温度和蒸发时间条件下的9,9′-联蒽有机薄膜.用原子力显微镜对制备的9,9′-联蒽薄膜形貌进行了观察,研究了9,9′-联蒽的生长模式,并讨论了其表面形貌及岛状晶核分布与生长条件之间的机理.同时,借助X射线衍射仪分析了薄膜的晶体结构.结果表明,在衬底温度为50℃、蒸发温度为180℃、蒸发时间为60s时能够获得具有良好晶体特性的均匀致密的多晶薄膜,其适合作有机场效应晶体管的有源层.
关键词:
9
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9′-联蒽
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表面形貌
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生长模式
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原子力显微镜
Journal of Alloys and Compounds
The crystal structures of Nd(4)Ga(2)O(9) and Sm(4)Ga(2)O(9) compounds synthesized by solid-state reaction at 1400degreesC are investigated. X-ray diffraction shows that Nd(4)Ga(2)O(9) and Sm(4)Ga(2)O(9) are monoclinic system with the space group P2(1)/c, and lattice parameters a = 7.7656(1) Angstrom, b = 10.9689(1) Angstrom, c = 11.4727(1) Angstrom, beta = 109.06(1)degrees for Nd(4)Ga(2)O(9), and a = 7.6613(1) Angstrom, b = 10.8546(1) Angstrom, c = 11.4080(1) Angstrom, beta = 108.80(1)degrees for Sm(4)Ga(2)O(9). The gallium atoms are in the center of distorted oxygen tetrahedra with an average Ga-O bond distance between 1.82 and 1.85 Angstrom. The rare earth atoms are sixfold or sevenfold coordinated by oxygen. The oxygen atoms are threefold and fourfold coordinated. The magnetization for these compounds clearly reflects paramagnetism. The magnetic susceptibility chi changes with temperature in a Curie-type manner. (C) 2004 Elsevier B.V All rights reserved.
关键词:
Nd(4)Ga(2)O(9);Sm(4)Ga(2)O(9);crystal structure;Rietveld refinement;x-ray diffraction;garnets
Physical Review B
The transport properties of S(9) clusters sandwiched between gold electrodes are investigated with a combination of density-functional theory and the nonequilibrium Green's-function method. In general we find a rather large conductance both when the cluster is oriented with its symmetry axis parallel to the transport direction and when it is perpendicular to it. In both cases the transmission is dominated by several closely spaced and extremely broad cluster molecular orbitals so that the transmission coefficient is almost flat around the gold Fermi level. This is only marginally affected by the external bias so that the I-V characteristic remains almost linear at least up to 1 V and for both the orientations. Furthermore the electron transport is only little affected by the bond length between the cluster and the electrodes, with the largest sensitivity found for the perpendicular orientation. Our results are rationalized by analyzing the device density of states projected over the various molecular orbitals.
关键词:
junction conductance;ab-initio;approximation;contacts
丰革
,
李浩
,
樊非
,
李树索
,
沙江波
稀有金属材料与工程
以Co基高温合金Co-9Al-9W-2Ta-0.02B成分为基础,分别添加了4at％和9at％的Mo元素替代W(使W+Mo含量为9at％),用电弧熔炼法制备了Co-9Al-xMo-(9-x)W-2Ta-0.02B合金(x=4,9),分别称为4Mo和9Mo合金,研究了Mo含量及时效温度对合金相组成、显微组织形貌和高低温拉伸性能的影响.结果表明:铸态合金由Co的固溶体γ相基体和金属间化合物γ'相Co3(Al,Me)组成(其中Me为合金元素W、Mo、Ta),γ’相位于y相界.1350℃/8 h固溶+800C/100h时效处理的4Mo合金γ相中均匀析出了与之共格并规则排列的立方形γ’相Co3(Al,Me),γ’相尺寸为200～300 nm；9Mo合金析出大量胞状和针状的κ-Co3Mo相以及少量的y’相.1350℃/8 h固溶+900℃/100h时效处理时4Mo合金的γ/γ’共格组织中也析出微量针状κ-Co3Mo相,而9Mo合金中的针状相明显粗化.4Mo合金的高低温抗拉伸强度与塑性均高于9Mo合金,合金在600℃以上发生反常屈服.
关键词:
新型Co基合金
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时效处理
,
相组成
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显微组织
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高温低力学性能
