Papers by Keyword: Buffer Layer

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Authors: Kazutoshi Kojima, Tetsuo Takahashi, Yuuki Ishida, Satoshi Kuroda, Hajime Okumura, Kazuo Arai
Authors: Ming Hua Pu, Guo Li, Xiao Hua Du, Yan Bing Zhang, Hua Ming Zhou, Rui Ping Sun, Zu Qiang Wang, Yong Zhao
Abstract: A new series of ReBiO3 (RBO, Re=Y, Sm or other lanthanide) layers have been prepared on single crystal LaAlO3 or SrTiO3 respectively by a low-cost chemical solution deposition (CSD) method, and their structures have been investigated. With deferent Re element, the ReBiO3 phase has a similar cubic lattice with the pseudo-cubic lattice parameter a’ of about 3.81~3.94Å, which is closely matched to that of the ReBa2Cu3Ox (RBCO). In addition, these ReBiO3 phase are stable when they are sintered on 750~1050°C. After annealed below 850°C in air, highly c-axis oriented ReBiO3 layers can be formed on the (100) plane of single crystal LaAlO3 or SrTiO3. Observed under SEM, these layers appear very dense, smooth, pinhole-free and crack-free morphology. With the matched lattice parameter, lower annealing temperature, good grain-orientation and smooth surface, ReBiO3 layers should be candidates for the buffer layers of RBCO coated conductor. As a proof, a superconducting layer of YBCO has been deposited also by a CSD approach on one of these layers and show good texture and expected superconductivity.
Authors: Feng Feng, Ti Ming Qu, Kai Shi, Rong Xia Huang, Wei Wu, Yan Yi Zhang, Shao Zhu Xiao, Jun Jun Wei, Xiao Hao Wang, Zheng He Han
Abstract: on beam assisted deposition (IBAD) is an important technique to fabricate the second generation high temperature superconducting (2G HTS) wires. Among the fabrication routes of 2G HTS long wires, IBAD route achieved the best performance in recent years. IBAD was adopted in this field in 1991 to obtain biaxially textured buffer layers, which helped to deposit high quality YBCO superconducting films on metallic substrates for the first time. Series of experimental and industrial researches on IBAD were carried out by many groups worldwide. And in the researches lasting for over two decades, the focused material for IBAD was changed from Yttria-Stabilized Zirconia (YSZ), Gd2Zr2O7 (GZO) to MgO. In this paper, the research progresses and the main achievements were briefly reviewed.
Authors: Takanori Kiguchi, Naoki Wakiya, Kazuo Shinozaki, Nobuyasu Mizutani
Authors: Xiao Ding, Zhi Ling Wang
Abstract: MIG welding overlaid austenitic stainless steel on low alloy Q345B. The overlay cladding comprises a transition layer and corrosion resistant layer. Overlaying specimens of transition layer with different thicknesses were prepared. The mechanical properties of joints were tested by micro-hardness, bending test and other methods. The results showed that the mechanical properties of specimen with ER309L welding wire as transition layer did not have splitting phenomena after being bended. There were no cracks. However, the specimen without transition layer had small crack or tiny cracks. When the transition layer thickness is changed, the performance of overlay cladding is essentially unchanged. The organizations of overlay cladding in four groups of specimens are similar, which are composed of austenite and ferrite, and ferrite was mostly distributed in strips and blocks.
Authors: Qi Ping Zhang, Qing Qing Fang, Wei Na Wang, Qing Rong Lv, Yan Mei Liu, Han Ming Zhang
Abstract: In this paper, we investigated the structure of SmCo films with different thickness and the effects of Cr buffer layer on the structure and morphology of SmCo/Cu thin films. Our data revealed that the magnetic properties of the samples were enhanced by the crystallization of SmCo which was promoted by the optimized Cu underlayers. We also found that the surface roughness can be decreased by Cr layer and the texture can be improved by prolonging the annealing time for thick SmCo film. Thus, we concluded that the magnetic properties of SmCo/Cu films can be further optimized by varying the thickness of Cr buffer layers.
Authors: Isabel Van Driessche, G. Penneman, J.S. Abell, E. Bruneel, Serge Hoste
Authors: Isidro Juvenal González Panzo, Pedro Edmundo Martin-Varguez, Andres Ivan Oliva
Abstract: ZnS is a promising material to substitute the CdS layer into the thin film solar cells, given its high reflectance and its wide wavelength to catch the solar radiation. ZnS films prepared by chemical bath technique present a low cost and a simple method to produce controlled films. However, the films quality depends on the chemical reagents and their concentration used. In this work, different chemical conditions are proposed for preparing ZnS films by the chemical bath deposition (CBD) technique. ZnS thin films were deposited at 80 °C by CBD by changing the concentrations of the chemical reagents NH4NO3, KOH, and maintaining the concentrations of ZnCl2 and thiourea (SC(NH2)2) in the chemical bath. The best conditions of the chemical reagents under the different deposition times (60 to 140 min) were obtained as a result of the experimentation done in order to produce ZnS thin films with good optical quality. The mean optical band gap energy measured on the prepared ZnS films was 3.77 eV, with a film thickness between 40 and 63 nm. The crystalline structure of films was amorphous as obtained by x-ray diffraction analysis. The surface roughness measured on the ZnS films was between 5 to 13 nm as obtained from atomic force microscopy images. Energy Dispersive Spectroscopy analysis show a Zn/S atomic ratio between 0.05 to 0.64.
Authors: R.J. Ong, J.T. Dawley, D.A. Payne, P.G. Clem
Authors: Philippe Odier, Antoine Girard, Yannick Cointe, S. Donet, Ze Ming Yu, Tristan Caroff, Andrea Cavallaro, Abdenacer Guibadj
Abstract: This work reports some new studies related to critical aspects in the development of coated conductors (CC). New bi-axially textured tapes based on commercial copper alloys were fabricated and tested as substrates for LZO buffer layer deposited by chemical solution deposition (CSD). Such a layer form cube texture on NiW5 and Cu55Ni45 with an identical or even better texture than that of the substrate. It was shown that a S c(2x2) sub-layer formed at the metallic surface as a positive effect on the nucleation. The crystallisation of LZO on Cu55Ni45 still has to be improved, being inhibited by trapped C in the film. Recent progresses using our continuous MOCVD system are shown. A CC fabricated by an all MOCVD process has been obtained on SS/YSZIBAD substrate with high transport critical current (170 A/cm-width, at 77 K). It is also shown that LZOMOD can efficiently protect Ni5W RABITS from oxidation during deposition of CeO2 layer by MOCVD under 30-40% O2 partial pressure. This opens the possibility to fabricate a CC on RABITS by MOCVD. This shows that a mixed MOD/MOCVD approach could be efficient. Finally a 2m long CC SS/YSZIBAD has been tested for fault current limiter applications. Best limitation was observed at 86 K where an equivalent energy of 340 J has been dissipated in the CC during 12 ms without apparent damage of the CC. In a subsequent operation, the CC was however destroyed. The causes are discussed in the perspective to design better architectures for this application.
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