金属基带表面电化学改性研究

发布时间：2018-02-07 11:49

本文关键词： 涂层导体织构化基带定向电沉积电化学抛光　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：YBCO等涂层导体的出现给高温超导体的实用化路线开辟了崭新的道路,涂层导体的结构由织构化基带、过渡层和超导层组成,基带作为载体,是决定超导材料性能的主要因素,考虑到现有的基带制备工艺,金属基带的表面质量不能满足涂层导体的要求,因此本文研究了一种提高Ni-5%W合金基带表面质量的脉冲电化学抛光方法。另一方面,高昂的基带制备成本是限制涂层导体大规模应用的主要障碍,因此我们希望利用电沉积技术,在无织构高强基带上制备出满足涂层导体外延生长需要的双轴织构的金属薄膜,则有可能开发出成本低廉的涂层导体织构化基带制造技术,大大降低涂层导体的制造成本。研究内容主要有以下几个方面：(1)采用脉冲电化学抛光工艺,研究不同脉冲参数即电流密度、脉冲频率、脉冲占空比对NiW基带的表面抛光效果的影响,通过扫描电镜和原子力显微镜对抛光后的基带表面微观形貌进行表征,并根据测试结果,调整实验参数,寻找最佳的脉冲电化学抛光工艺,结果表明在合适的抛光工艺下可以获得纳米级粗糙度的基带表面质量。(2)在镍基带上电沉积铜层。通过脉冲电化学抛光对金属镍基带进行表面预处理获得平整光滑的表面,探索在镍基带上电沉积制备连续致密铜层实验最佳的电沉积工艺参数,结果表明,在最佳电沉积工艺下可以制备连续致密完整的的铜薄膜,为后续银薄膜的沉积提供好的过渡层。(3)在铜基带上电沉积银薄膜。通过脉冲电化学抛光方法对金属铜基片进行表面改性,首先考察电镀技术是否具有定向作用,并探讨不同的脉冲工艺参数下,金属镀层的织构,寻找获得(111)相对取向择优度最强的银薄膜的实验工艺参数,结果表明电镀确实具有定向作用,在合适脉冲参数下制备了连续致密(111)取向择优的银薄膜,(4)用类似的定向电镀原理性装置在金属基带上沉积银薄膜。通过选择定向作用,制备出了具有(200)择优取向的双轴织构的Cu/Ag复合基带。(5)在双轴织构化的镍钨基带,通过化学沉积制备了具有(200)取向择优的Ag薄膜缓冲层。热处理后,铜基片上沉积的Ag薄膜由(111)取向择优转变为(200)取向择优。
[Abstract]:The appearance of coating conductors such as YBCO has opened a new way for the practical route of high temperature superconductors. The structure of coating conductors is composed of textured baseband, transition layer and superconducting layer, which is the main factor that determines the properties of superconducting materials. Considering the existing substrate preparation technology, the surface quality of metal substrate can not meet the requirements of coated conductors. Therefore, a pulsed electrochemical polishing method to improve the surface quality of Ni-5%W alloy substrate is studied in this paper, on the other hand, The high cost of substrate preparation is the main obstacle to limiting the large-scale application of coated conductors. Therefore, we hope to use electrodeposition technology to prepare biaxial textured metallic films on the high strength substrate without texture to meet the requirements of epitaxial growth of coated conductors. It is possible to develop a low-cost fabrication technology for textured baseband of coated conductors, which greatly reduces the manufacturing cost of coated conductors. The main research contents are as follows: 1) Pulsed electrochemical polishing process is adopted. The effects of different pulse parameters such as current density, pulse frequency and pulse duty ratio on the surface polishing of NiW baseband were studied. The micromorphology of the polished baseband was characterized by scanning electron microscope and atomic force microscope. According to the test results, the experimental parameters are adjusted to find the best pulse electrochemical polishing process. The results show that the surface quality of nanoscale roughness can be obtained by electrodeposition of copper layer on nickel substrate under proper polishing process. The smooth surface is obtained by surface pretreatment of metal nickel base band by pulse electrochemical polishing. The optimum parameters for electrodeposition of continuous dense copper layer on nickel substrate were explored. The results showed that continuous dense and complete copper films could be prepared under the optimum electrodeposition process. To provide a good transition layer for the subsequent deposition of silver films, silver films were electrodeposited on copper substrates. Surface modification of metallic copper substrates was carried out by pulse electrochemical polishing. At the same time, the texture of metal coating under different pulse process parameters is discussed, and the experimental technological parameters of silver film with the strongest relative orientation preference are obtained. The results show that the electroplating does have directional effect. In this paper, a continuous dense silver thin film with preferred orientation has been prepared under suitable pulse parameters. Silver thin films have been deposited on metal substrates using a similar directional electroplating device. In this paper, the Cu/Ag composite substrate with biaxial texture with #number0#) orientation was prepared. The Ni-W substrate with biaxial texture was prepared by chemical deposition. The Ag film buffer layer with the preferred orientation was prepared by chemical deposition. After heat treatment, the Ag film was prepared by chemical deposition. The Ag thin films deposited on copper substrates have a preferred orientation from 111) to 200).
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ153

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