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1.
氧化钇钡铜(YBCO)涂层导体在77K的液氮温区具有交流损耗低、不可逆场高、载流能力强等优点,是目前制备液氮温区磁体的唯一选择。目前,低成本、高性能的YBCO涂层导体已成为国际实用化高温超导材料的研究重点。镍钨合金具有磁性小、强度高、良好的高温抗氧化性、易于形成立方织构等优点,是最具应用前景的涂层超导体基带材料[1-2]。其中钨元素的含量、分布均匀性对镍钨合金的强度、  相似文献   

2.
钇系涂层超导体金属基带再结晶织构及显微组织   总被引:4,自引:1,他引:3  
用轧制-再结晶热处理方法制备了强立方织构的纯Ni基带和无磁性Cu-Ni合金基带,为第二代钇钡铜氧高温超导带材提供了较好的基带材料,用三维取向分布函数(ODF)和ψ扫描曲线研究了织构,用金相显微镜研究了截面显微组织。分析表明,Cu0.70Ni0.30合金和纯Ni在再结晶温度为1000℃时,获得最强的立方结构;Cu0.85Ni0.15在900℃时获得最强的立方织构,立方织构强度大小各不相同,3种不同组分金属都获得了均匀的等轴的等轴晶粒组织,其中Cu0.85N0.15的晶粒大于Cu0.70Ni0.30和纯Ni的晶粒,Cu0.85Ni0.15和Cu0.70Ni0.30都出现了退火孪晶。  相似文献   

3.
由Philips引进的PW1700X射线衍射仪织构测量系统只能用反射法,按螺旋线扫测极目数据,测绘极角。α≤85°的不完整极图。经功能开发后,建立了织构分析测算系统,织构分析应用软件包,包括不完整极图测量与ODF(取向分布函数)计算,回算全极图与反极图,可彩色屏显考贝,并能进行织构的定量分析。适用于立方和六方品系多晶织构材料分析。近两年应用表明,软件功能优异。  相似文献   

4.
采用表面氧化外延(SOE)方法, 在金属基底上研制NiO隔离层. 通过研究温度、时间等工艺参数对形成立方织构NiO的影响, 摸索出一套可获得单一、尖锐的立方织构NiO, 重复性好, 适合于长带发展的工艺技术. 同时研究了金属基带的表面状态、织构取向对NiO(100)表面的影响. X射线极图观测可直观地看到单一的立方织构, φ扫描检测其半高宽(FWHM)均为7.5°. 扫描电镜观察NiO(100)膜层表面形貌, 无裂纹且较为致密.  相似文献   

5.
YBa2Cu3O7-x涂层导体的研究进展   总被引:16,自引:1,他引:16  
以YBa2Cu3O7-2(YBCO)超导涂层为导体的第二代高温超导带材由于其优异的本征性能,吸引着科学家不断探索和研究其实用成材技术。近年来,百米级长带的研制成功,使其成为当前国际上超导研究的热点。综述了近年来二代超导带材的发展状况,并对在镍和镍合金基带上制备涂层导体的工艺技术以及其基本结构特征做了较为系统的介绍,包括基带的制备技术、隔离层的生长、化学法和物理气相沉积法生长YBCO等。  相似文献   

6.
用退火使条带织构装饰在全芳共聚酯的取向膜上,在偏光显微镜下同时观察到微纤和条带。微纤分三个层次,即直径分别为数十微米的微纤束、数微米的微纤和0.3微米的亚微纤,退火后三个层次的微纤松弛成不同的形态,微纤束仍笔直沿剪切方向取向,微纤松弛成螺旋形,而亚微纤松弛成波浪形从而观察到条带织构:微纤直径越小越易松弛,另一方面,非取向态织构退火后由亚微纤形成的条带装饰结果直观地揭示了微区内外分子指向矢的分布和它们在边界上的变化。退火时条带织构的形成被解释为分子的弹性回缩力缓慢发生作用使分子松弛所致。  相似文献   

7.
为了实现YBa2Cu3O7-x(YBCO)涂层导体在电力工业中的实际应用,必须有效增加YBCO超导层的厚度。提出一个强磁场辅助TFAMOD法制备YBCO厚膜的新工艺,并从磁热力学和磁性物理出发理论分析其可行性。沿垂直基底平面方向施加强磁场时,磁场将促进c轴取向YBCO晶核的形成,诱导厚膜中非c轴取向晶核转动到c轴平行磁场取向的位置。另外,取向晶粒间磁性相互作用力使晶粒沿磁场方向定向聚合,有利于获得致密的厚膜。因此,强磁场辅助TFA—MOD法有望制备高临界电流密度的YBCO织构厚膜。  相似文献   

8.
采用调制偏压射频控溅射技术在多晶Hastelloy-C金属基带上制备钇稳定的ZrO2薄膜(YSZ),得到了c-轴织构和部分平面内双轴织构的YSZ薄膜。用X射线衍射θ-2θ扫描、ω扫描和φ扫描对YSZ薄膜的织构进行了测量,并研究了沉积条件对织构形成的影响。  相似文献   

9.
采用调制偏压射频磁控溅射技术在多晶HasteloyC金属基带上制备钇稳定的ZrO2薄膜(YSZ),得到了c轴织构和部分平面内双轴织构的YSZ薄膜。用X射线衍射θ2θ扫描、ω扫描和扫描对YSZ薄膜的织构进行了测量,并研究了沉积条件对织构形成的影响。  相似文献   

10.
本研究采用织构分析的三维取向分布函数法研究了Cu-Zn-Al形状记忆合金的织构与弹性各向异性。研究结果表明:1.两相Cu-Zn-Al合金板材β-相的构与钢板相似,它在欧拉空间系由A-管和B-管纤维织构组成的,而α-相的强构与冷轧黄铜板的织构相似。2、板材表面与内部的织构具有一定的差别,对于β-相的织构,这种差异明显;而对于α-相的织构只是强弱之差,3.弹性模量随与轧向偏离的角度而变,对于具有β-相  相似文献   

11.
The structure was studied and the texture formation process was investigated in tapes made of Cu–Ni–Me ternary alloys (Me = Fe, Cr, V, or Mn) during cold deformation by rolling to a degree of ~99% with subsequent recrystallization annealing. It was shown that it is generally possible to create a perfect cubic texture in a thin ribbon made of ternary alloys based on copper and nickel to which a period 4 d-element (iron, chromium, or vanadium) was added. This makes these tapes promising as substrates in the technology for producing second-generation high-temperature superconductor tapes. The optimal annealing conditions were determined, under which, in the studied alloys, a perfect biaxial near-single-crystalline texture can be obtained with a content of cubic grains {001}〈100〉 ± 10° on the surface of the textured ribbon of above 99%.  相似文献   

12.
Ultrathin carbon films were grown on different types of metallic substrates. Free‐standing foils of Cu and Ni were prepared by electroforming, and a pure Ni film was obtained by galvanic displacement on a Si wafer. Commercial foil of Ni 99.95% was used as a reference substrate. Carbon films were grown on these substrates by chemical vapour deposition in a CH4‐H2 atmosphere. Obtained films were characterized by Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, and ultraviolet photoemission spectroscopy. The XPS at grazing collection angle was used to determine the thickness of carbon films. Depending on the deposition parameters, the films of graphene or graphite were obtained on the different substrates. The uniformity of graphene and its distribution over the sample area were investigated from Raman data, optical images, and XPS chemical maps. The presence of graphene or graphite in the films was determined from the Raman spectra and Auger peak of C KVV. For this purpose, the D parameter, which is a fingerprint of carbon allotropes, was determined from C KVV spectra acquired by using X‐rays and electron beam. A formation of an intermediate layer of metal hydroxide was revealed in the samples with graphene overlayer.  相似文献   

13.
The surfaces of the alloy based on Zr2Ni doped by silicon (3 at.%) in the amorphous and crystalline states and of the Zr and Ni foils were electrochemically modified for the first time. The modification was carried out in the ionic liquid in the galvanostatic regime. The much more uniform distribution of the nanosized fragments can be obtained and stability of their geometric shapes can be retained in the absence of intergrain boundaries and texture in the amorphous materials.  相似文献   

14.
由聚电解质自组装多层膜制备微孔薄膜   总被引:1,自引:0,他引:1  
带有相反电荷的聚电解质通过静电作用交替沉积可以得到自组装多层膜,由于这种技术可操作性强,用途广泛,近十几年来已有了大量的研究.聚电解质多层膜在一定条件下可以形成纳米孔和微米孔.Fu等研究了聚丙烯酸和聚乙烯基吡啶组成的氢键自组装多层膜在碱溶液中溶去其中的聚丙烯酸后,剩下的聚乙烯基吡啶重构形成微孔薄膜.Mendelsohn等发现将聚丙烯酸和聚烯丙基胺自组装而成的多层膜浸入pH=2.4左右的溶液中可制备微孔薄膜.但这些方法并不能使强聚电解质多层膜形成多孔结构。  相似文献   

15.
Ni‐diamond composite coatings with high concentration and uniform distribution of diamond particles were prepared by using sediment co‐deposition (SCD) technique from Watts‐type electrolyte without any additives. The surface and cross‐section morphology was evaluated by optical microscope (OM) and scanning electron microscopy (SEM). It was demonstrated that the Ni‐monolayer diamond composite coatings ~40 ± 5 µm was successfully prepared by the new developed setup for SCD technique. Using this new developed setup, high concentration and uniform distribution of diamond particles of Ni‐monolayer diamond composite coatings were easily fabricated. The wear resistance and cutting performance of obtained composite coatings were also investigated. The results revealed that anti‐wear and cutting performance is superior to those prepared via conventional co‐electrodeposition (CED) technique and pure Ni coatings. In the SCD process, with the increasing diamond content, the wear resistance is approximately the same, and the cutting performance decreases. Therefore, not only the diamond particle content is responsible for the wear resistance and cutting performance, the distribution of diamond particles is also very important factor. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

16.
Cell rolling is an important physiological and pathological process that is used to recruit specific cells in the bloodstream to a target tissue. This process may be exploited for biomedical applications to capture and separate specific cell types. One of the most commonly studied proteins that regulate cell rolling is P-selectin. By coating surfaces with this protein, biofunctional surfaces that induce cell rolling can be prepared. Although most immobilization methods have relied on physisorption, chemical immobilization has obvious advantages, including longer functional stability and better control over ligand density and orientation. Here we describe chemical methods to immobilize P-selectin covalently on glass substrates. The chemistry was categorized on the basis of the functional groups on modified glass substrates: amine, aldehyde, and epoxy. The prepared surfaces were first tested in a flow chamber by flowing microspheres functionalized with a cell surface carbohydrate (sialyl Lewis(x)) that binds to P-selectin. Adhesion bonds between P-selectin and sialyl Lewis(x) dissociate readily under shear forces, leading to cell rolling. P-selectin immobilized on the epoxy glass surfaces exhibited enhanced long-term stability of the function and better homogeneity as compared to that for surfaces prepared by other methods and physisorbed controls. The microsphere rolling results were confirmed in vitro with isolated human neutrophils. This work is essential for the future development of devices for isolating specific cell types based on cell rolling, which may be useful for hematologic cancers and certain metastatic cancer cells that are responsive to immobilized selectins.  相似文献   

17.
添加剂的吸附行为及其对Ni沉积层性能的影响   总被引:4,自引:0,他引:4  
采用电化学及X射线衍射等方法研究有机添加剂苯磺酸钠、苯亚磺酸钠和糖精的吸附作用及其对Ni电沉积层的电化学活性、晶粒尺寸、织构及显微硬度的影响.结果表明,苯亚磺酸钠和糖精使Ni沉积层的电化学活性提高,(111)晶面的织构系数明显增大,而使(290)晶面的织构系数减小,还导致沉积层的晶粒尺寸显著减小和显微硬度提高;然而,苯磺酸钠对沉积层的活性及织构影响很小.讨论了上述添加剂的作用.  相似文献   

18.
添加剂的吸附行为及其对Ni沉积层性能的影响   总被引:4,自引:0,他引:4  
采用电化学及X射线衍射等方法研究有机添加剂苯磺酸钠、苯亚磺酸钠和糖精的吸附作用及其对Ni电沉积层的电化学活性、晶粒尺寸、织构及显微硬度的影响.结果表明,苯亚磺酸钠和糖精使Ni沉积层的电化学活性提高,(111)晶面的织构系数明显增大,而使(200)晶面的织构系数减小,还导致沉积层的晶粒尺寸显著减小和显微硬度提高;然而,苯磺酸钠对沉积层的活性及织构影响很小.讨论了上述添加剂的作用.  相似文献   

19.
Macroporous polymers of pure meta-divinylbenzene (meta-DVB) and pure para-divinylbenzene (para-DVB) have been prepared in the presence of toluene and 2-EHA as pore forming agents. The formation of the pore structure has been studied during the polymerization by pore-size distribution measurements, together with determination of the specific surface area from nitrogen sorption isotherms using the BET treatment. In addition, the morphology and texture have been characterized by SEM during the polymerization process. Large differences in the pore-size distribution among all the polymer samples are found. The polymers prepared in toluene as porogen have a pore-size distribution, which mainly consists of small pores, while large pores appear with 2-EHA as porogen. In the presence of 2-EHA, a major change in the pore-size distribution is also observed when the monomer is shifted from para-DVB to meta-DVB, leading to a bimodal distribution. The texture characterization by SEM shows details and discriminates the samples in consistency with what may be expected from pore-size distribution measurements. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3973–3990, 1999  相似文献   

20.
郝志显  李全芝 《化学学报》2002,60(7):1339-1345
使用直接还原镍盐前体[Ni(NO_3)_2/γ-Al_2O_3, NiAc_2/γ-Al_2O_3或Ni (NO_3)_2-NiAc_2/γ-Al_2O_3]和镍氧化物前体的方法制备催化剂,研究了它们的 表面特征和甲苯加氢抗硫性能。还原镍盐得到的催化剂比还原其焙烧成的氧化物制 得的催化剂金属的还原和分散程度高。Ni(NO_3)_2-NiAc_2/γ-Al_2O_3分解得到的 氧化物前体的TPR在约415 ℃出现了较小数量的块状NiO的还原峰;而Ni(NO_3)_2- NiAc_2/γ-Al_2O_3的TPR中镍盐分解成氧化物时的耗氢量变小。用氢溢流的概念和 镍盐分解时的耗氢量可以将TPR的结果和金属的分散性关联起来。在镍盐前体催化 剂上甲苯的加氢具有较高的活性,而两种盐摩尔比为1:1时,盐前体催化剂反应活 性出现了一极大值,同时盐和氧化物前体催化剂都给出了抗硫性能的极大值。  相似文献   

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