节点文献

高分子辅助化学溶液沉积法制备涂层导体缓冲层长带

Preparation of Buffer Layer Tape for Coated Conductors by Polymer Assisted Chemical Solution Deposition

【作者】 雷鸣

【导师】 赵勇;

【作者基本信息】 西南交通大学 , 材料学, 2012, 博士

【摘要】 涂层导体是国际高温超导材料目前研究的热点,缺乏高效率低成本的制备技术是其产业化和大规模应用的瓶颈,而缓冲层的制备技术是其中一个急需解决的关键问题。本论文是以低成本、连续化、易产业化的、环境友好的制备技术为研究目标,为涂层导体框架提供了两种可选方案:一、低成本制备800℃左右NiO(200)/SmBiO3双层缓冲层,氩气气氛NiO(200)缓冲层的制备工艺是本论文的创新之处(已申请专利);SmBiO3缓冲层是本课题组自主研发具有独立知识产权的缓冲层,所以SmBiO3/NiO(200)/NiW双层缓冲层将成为一种新颖、低成本的涂层导体框架形式;首先优化高分子辅助化学溶液法(PACSD)与旋涂法相结合制备RE:CeO2缓冲层短样的工艺参数;然后在此基础上,研究了PACSD法与浸涂技术相结合制备Sm0.2Ce0.8O1.9(SCO)的工艺;最后研究了PACSD法与狭缝涂覆技术相结合涂覆制备SCO湿膜的工艺,在静态热处理工艺的基础上,采用我们独立研发设计制造的高温超导涂层导体带材连续制备系统,在该系统上开发出一种动态连续制备SCO/NiW缓冲层长带的工艺。PACSD制备缓冲层技术从静态短样制备到动态长带制备取得了显著的进展,首次展示出采用化学沉积法制备的高质量缓冲层长带,为大规模涂层导体产业化提供了很好的技术储备。本文的主要结果包括以下几个方面:研发出采用自氧化外延法制备NiO(200)缓冲层的工艺。在氩气气氛下800℃特定条件下制备出NiO(200)缓冲层,厚度约为5μm。NiO(200)薄膜具有双轴织构性、薄膜表面平整致密、无微裂纹。与1000℃多度高温下制备的结果相比,本实验结果无论在厚度控制还是薄膜的附着力均有显著提高。采用高分子辅助化学溶液沉积方法在NiO(200)上面沉积制备了SmBi03缓冲层,SmBi03薄膜双轴织构、表面平整致密、无微裂纹。所开发出的SmBi03/NiO(200)/NiW双层缓冲层成为一种新颖、低成本制备涂层导体的框架形式。研发出采用旋涂法与PACSD法相结合制备SCO和Gd0.3Ceo.701.8(GCO)单层缓冲层工艺。在Ni-5%W合金基带上成功地制备织构优良、表面平整致密,且厚度可达180nm的SCO单层缓冲层。并采用外延沉积方法在上面完成高性能YBCO超导层制备,超导转变温度Tc=87K,且临界电流密度在77K自场下可达1.0MA/cm2。并制备厚度达180nmGCO缓冲层,在上面采用外延沉积法获得高性能GBCO超导层,GBCO薄膜表面平整致密、无微裂纹。通过采用高分子辅助化学溶液沉积及稀土离子掺杂使得纯CeO2缓冲层的临界厚度得到提高,为高温超导涂层导体提供了一种制备单一缓冲层的途径。三、研发出采用浸涂技术与PACSD法相结合制备SCO缓冲层工艺。浸涂技术与旋涂法相比,更适合应用于大规模连续涂层导体长带制备。通过对溶胶浓度、提拉速度等影响因素进行详细分析,获得最佳制备工艺参数:浓度PAA10%,提拉速度10mm/min,H2/Ar气氛下1100℃热处理0.5h。采用该工艺制备的SCO样品,薄膜厚度可达250nm,具有良好的双轴织构性、平整致密、无微裂纹。采用无氟MOD方法与浸涂技术相结合在SCO上面制备YBCO超导层,YBCO的(001)系列峰值都能明显显现,薄膜表面完整致密、无微裂纹。四、研发出一种狭缝涂覆技术与PACSD法相结合动态制备SCO缓冲层长带的工艺。自主研发设计制造了具有独立知识产权的高温超导涂层导体带材连续制备系统,并在该系统上研发出一种动态连续制备RE:CeO2缓冲层长带的工艺。通过对溶液的黏度、带移动速率、溶液释放速率等涂覆影响因素进行了详细分析,得到最佳涂覆工艺参数:高分子辅助溶液PAA15wt.%;带移动速度为0.20m/h;溶液释放速度为0.5ml/h;冲模间距固定为一液珠刚好充满基带宽度为基准。采用该工艺制备的SCO样品,样品厚度150nm,具有双轴织构性、整体织构度高达90%,薄膜表面平整致密、无微裂纹。首次展示出采用化学沉积法可以制备出高质量的缓冲层长带。

【Abstract】 Coated conductor is hot in current study on international high-temperature superconducting materials, but there is a bottleneck in its industrialization and large-scale application, i.e. the lack of a preparation process with high efficiency and low cost, particularly the lack of a buffer layer preparation process which is a key problem requiring urgent settlement.Aiming at a preparation process with low cost, continuity and easy industrialization, this paper provides two available schemes for coated conductor framework:one is to prepare NiO(200)/SmBiO3double buffer layers at about800℃with low cost. Such preparation process of NiO(200) buffer layer in argon atmosphere is our innovation for which patent protection has been applied for and SmBiO3buffer layer with independent intellectual property right is also independently developed by this research team, so SmBiO3/NiO(200)/NiW double buffer layer technique offers a unique and low-cost framework approach for the preparation of coated conductor. The other is to firstly optimize process parameters of short samples of RE:CeO2buffer layer prepared by using the Polymer Assisted Chemical Solution Deposition (PACSD) method combined with spin coating technique, then on such basis, to study Sm0.2Ce0.8O1.9preparation process with combination of PACSD method with dip coating technique, and finally to study the coating preparation technique of SCO polycrystalline wet film by combining PACSD method with slot-die coating. Based on the static heat treatment process, a dynamic continuous preparation system of high-temperature superconducting coated conductor tape is independently developed, designed and manufactured. On the basis of this system, a dynamic continuous preparation process of SCO/NiW buffer layer long tape is developed. Considerable progress has been made in the technique of preparing buffer layers by the PACSD method, i.e. from static preparation of short samples to dynamic preparation of long tapes. With the first preparation of high-quality buffer layer tape using chemical solution deposition method, it provides good technical reserves for future large-scale coated conductor industrialization.This paper mainly includes the following outcomes:I. A technique of preparing NiO(200) buffer layer by oxidization and epitaxy method.NiO(200) buffer layer with a thickness of5μm has been successfully prepared at800℃in ordinary argon atmosphere.The NiO(200) buffer layer film has bi-axial texture with compact and smooth surface, without micro-crack, featuring better adherence and more uniform thickness compared with those of the reported film prepared at high temperature of more than1000℃. SmBiO3buffer layer has been also successfully deposited on the NiO(200) buffer layer with the use of Polymer Assisted Chemical Solution Deposition (PACSD) method. The SmBiO3buffer layer film has bi-axial texture with compact and smooth surface, without micro-crack. The newly developed SmBiO3/NiO(200)/NiW combined double buffer layers offer a unique and low-cost structure approach for the preparation of coated conductor.Ⅱ. Optimal preparation process of Smo.2Ce0.8O1.9(SCO) and Gd0.3Ce0.7O1.8(GCO) single buffer layers by spin coating method and the PACSD methodSCO single buffer layer having a thickness of180nm and good texture with flat and compact surface is successfully prepared on Ni-5%W alloy tape, and optimal YBCO superconducting layer is prepared with the use of epitaxially deposited YBCO film above it, the superconducting transition temperature is Tc=87K and the critical current density may reach1.0MA/cm2at77K self-field. GCO buffer layer,180nm thick, has also been prepared. GBCO superconducting layer of sound performance is prepared with succeeded epitaxially deposition unto it, presenting a flat and compact film surface without micro-crack. The critical thickness of the CeO2buffer layer is increased by PACSD and mixing of rare earth ions, providing a new method for preparation of high-temperature superconducting coated conductors of single buffer layer.Ⅲ. A preparation process of SCO buffer layer by dip coating technique and the PACSD methodThe dip coating technique is more applicable to large-scale continuous preparation of long tapes of coated conductors compared with the spin coating method. Optimal preparation process parameters are obtained based on intensive analysis of such impact factors as sol concentration and withdrawal speed, including PAA10%; withdrawal speed:10mm/min; heat treatment in H2/Ar atmosphere at1100℃for0.5h. Such process is employed to obtain SCO sample, the film thickness may be up to250nm, and the film have good bi-axial texture with compact and smooth surface without micro-crack. YBCO superconducting layer has been prepared onto SCO by the fluorine-free MOD method and the dip coating technique, distinct (001) series peaks appear, and the YBCO film has completeness, compactness and no micro-crack surface.Ⅳ. A technique of preparing SCO buffer layer long tape by slot die technique and the PACSD methodA continuous preparation system of high-temperature coated conductor tape is researched, developed, designed and manufactured, which has independent intellectual property. On the basis of this system, a dynamic continuous preparation process of RE:CeO2buffer layer long tape is developed. Through intensive analysis on impact factors such as solution viscosity, tape moving speed, solution release speed, etc, optimal preparation process parameters are obtained, including polymer assisted solution PAA15wt.%, tape moving speed0.20m/h, solution release speed0.5ml/h. The die spacing shall be constant to enable a bead to be just full of a tape width. With respect to the SCO sample prepared with the use of this technique, it is150nm thick and has bi-lateral texture with more than90%integrity as well as impact and smooth surface without micro-crack, initiating the ability in preparation of high-quality buffer layer long tape with the use of fluorine-free chemical solution deposition method.

节点文献中: 

本文链接的文献网络图示:

本文的引文网络