本文選題：YBCO超導(dǎo)帶材 + CeO_2/YSZ/Y_2O_3緩沖層　； 參考：《電子科技大學(xué)》2014年博士論文

【摘要】：以YBa2Cu3O7-δ(YBCO)為代表的第二代高溫超導(dǎo)帶材具有優(yōu)異的電學(xué)性能,在電力傳輸、電能存儲、強(qiáng)磁場等領(lǐng)域有著非常廣闊的應(yīng)用前景。為獲得高性能的YBCO超導(dǎo)帶材,必須制備出高質(zhì)量的緩沖層來傳遞雙軸織構(gòu)以及阻擋基帶和超導(dǎo)材料間的互擴(kuò)散。目前在制備過程中仍然存在大量的瓶頸問題需要解決:如晶粒間夾角的控制、新型緩沖層結(jié)構(gòu)的選取和制備、成本的降低等。本論文基于軋制輔助雙軸織構(gòu)(RABiTS)路線,從薄膜的生長工藝入手,對薄膜織構(gòu)、表面形貌的調(diào)控機(jī)制以及緩沖層對超導(dǎo)薄膜載流能力影響的機(jī)理開展了系統(tǒng)的研究工作。主要內(nèi)容如下:1、采用直流磁控反應(yīng)濺射法在雙軸織構(gòu)的Ni-5at.%W(NiW)基帶上制備雙面CeO2/YSZ/Y2O3薄膜,通過調(diào)整水分壓、濺射氣壓和沉積溫度等工藝條件,進(jìn)行了三層緩沖層結(jié)構(gòu)的生長控制研究。在最優(yōu)工藝條件下制備的Y2O3薄膜面外織構(gòu)為1.5o,面內(nèi)織構(gòu)為4.8o,表面均方根粗糙度Rrms為2 nm。并通過對Y2O3薄膜應(yīng)力變化與薄膜生長機(jī)理的分析,建立兩種生長模型闡述Y2O3薄膜面外織構(gòu)大幅度改善的原因。采用濺射原子擴(kuò)散、成核的理論模型對CeO2薄膜表面形貌及晶粒變化進(jìn)行了理論分析,并結(jié)合工藝實(shí)驗(yàn)實(shí)現(xiàn)了平整致密模板層的制備,表面均方根粗糙度Rrms小于3 nm。為制備高質(zhì)量的YBCO帶材提高了保證。2、利用超導(dǎo)電流在YBCO中傳輸模型計(jì)算了晶界夾角對YBCO薄膜載流能力的影響,并通過對比在具有不同織構(gòu)緩沖層樣品制備YBCO薄膜的臨界電流密度,從實(shí)驗(yàn)上對計(jì)算結(jié)果進(jìn)行驗(yàn)證。進(jìn)行了對緩沖層表面形貌對YBCO載流能力影響的規(guī)律進(jìn)行研究,選取不同表面形貌的CeO2/YSZ/Y2O3緩沖層,在其上采用相同的工藝制備YBCO薄膜,利用高分辨X射線衍射譜計(jì)算不同樣品的螺型位錯(cuò)與刃型位錯(cuò)密度,理論分析了不同表面粗糙度對YBCO位錯(cuò)密度的影響,對比不同樣品YBCO薄膜的臨界電流密度,解釋了緩沖層表面粗糙度對YBCO薄膜臨界電流密度影響的原因。最后在最優(yōu)雙面多層緩沖層上制備的YBCO薄膜雙面臨界電流密度Jc一致,雙面臨界電流Ic值為500 A/cm-width。3、為了解決直流濺射中靶材中毒導(dǎo)致沉積速率下降的難題以實(shí)現(xiàn)緩沖層的快速高質(zhì)量制備,采用交流中頻磁控反應(yīng)濺射制備Y2O3種子層,研究中頻電壓、濺射氣壓對Y2O3薄膜取向和表面形貌的影響規(guī)律。Y2O3種子層制備效率提高到直流濺射的3倍,從5 m/h的制備效率提升到15 m/h,甚至最高可達(dá)到50 m/h,這對于YBCO超導(dǎo)帶材的工業(yè)化具有非常重要的意義。在中頻濺射制備的Y2O3薄膜上成功制備了良好的面內(nèi)外織構(gòu)的YSZ阻擋層和CeO2模板層,進(jìn)一步證明了中頻磁控反應(yīng)濺射技術(shù)能夠快速制備高質(zhì)量緩沖層的優(yōu)點(diǎn)。4、簡化緩沖層制備工藝以降低工藝成本,并提高帶材的工程實(shí)用性,提出了全導(dǎo)電TiN/SrRuO3(SRO)緩沖層新結(jié)構(gòu),并采用脈沖激光沉積技術(shù)進(jìn)行了驗(yàn)證。研究不同制備工藝下TiN種子層的生長規(guī)律,XRD測試結(jié)果表明TiN和SRO具有良好的面內(nèi)外織構(gòu),SRO表面粗糙度Rrms小于5 nm。I-V曲線測試全導(dǎo)電緩沖層SRO/TiN在常溫具有良好的導(dǎo)電特性。在其上采用直流濺射法制備YBCO薄膜,R-T曲線表明采用全導(dǎo)電緩沖層的超導(dǎo)帶材在轉(zhuǎn)變溫度附近電阻率僅約為2×10-5Ω?cm。全導(dǎo)電緩沖層結(jié)構(gòu)為YBCO超導(dǎo)帶材緩沖層技術(shù)提出了新的途徑。
[Abstract]:The second generation high temperature superconducting strip, represented by YBa2Cu3O7- Delta (YBCO), has excellent electrical properties. It has a very broad application prospect in the fields of power transmission, electric energy storage and strong magnetic field. In order to obtain high performance YBCO superconducting strip, high quality buffer layer must be prepared to transfer biaxial texture and block the base band and superconducting material. A large number of bottlenecks still exist in the process of preparation, such as the control of the angle between grains, the selection and preparation of the new structure of the buffer layer, and the reduction of the cost. This paper is based on the rolling assisted dual axis texture (RABiTS) route, starting with the growth process of the film, and regulating the texture and surface morphology of the film. The mechanism of the effect of the system and the buffer layer on the current carrying capacity of the superconducting thin film is systematically studied. The main contents are as follows: 1, the two-sided CeO2/YSZ/Y2O3 film is prepared on the Ni-5at.%W (NiW) base band of the dual axis texture by DC magnetron sputtering, and the three layers are carried out by adjusting the water pressure, the splash pressure and the deposition temperature. The growth control of the buffer layer structure. The surface texture of Y2O3 thin film prepared under the optimal process conditions is 1.5o, the texture in the surface is 4.8o, the surface RMS roughness is 2 nm., and the two growth models are set up to explain the reason for the large improvement of the texture of the Y2O3 film through the analysis of the stress change of the Y2O3 film and the growth mechanism of the thin film. The theoretical model of the surface morphology and grain change of CeO2 thin film by sputtering atom diffusion and nucleation is theoretically analyzed, and the preparation of the smooth and dense template layer is realized with the process experiment. The surface RMS roughness is less than 3 nm. for the high quality YBCO strip to be prepared, and the.2 is improved and the superconducting current in YBCO is used to transfer the model. The influence of the grain boundary angle on the current carrying capacity of the YBCO film was calculated. By comparing the critical current density of the YBCO thin film with different texture buffer layers, the results were verified experimentally. The rules of the influence of the surface morphology of the buffer layer on the YBCO current carrying capacity were studied, and the CeO2/YS of different surface morphology was selected. The Z/Y2O3 buffer layer is used to prepare the YBCO thin film on the same process. The snail dislocation and the edge dislocation density of different samples are calculated by high resolution X ray diffraction. The influence of different surface roughness on the dislocation density of YBCO is theoretically analyzed. The critical current density of different samples of YBCO films is compared, and the surface roughness of the buffer layer is explained. The reason for the influence of the critical current density on the YBCO film. Finally, the two side critical current density (Jc) of the YBCO film prepared on the optimal double-sided multilayer buffer layer is consistent, and the double side critical current is 500 A/cm-width.3. In order to solve the difficult problem of the deposition rate of the target poisoning caused by the direct current sputtering, the rapid and high quality preparation of the buffer layer is achieved. Y2O3 seed layer was prepared by AC medium frequency magnetron sputtering, and the effect of medium frequency voltage and sputtering pressure on the orientation and surface morphology of Y2O3 thin film.Y2O3 seed coating efficiency was increased to 3 times of DC sputtering, the preparation efficiency from 5 m/h to 15 m/h, or even up to 50 m/h, for the industrialization of YBCO superconducting strip. It is very important that a good YSZ barrier layer and CeO2 template layer are successfully prepared on the Y2O3 thin film prepared by medium frequency sputtering, and the advantages of the medium frequency magnetron reactive sputtering technology can be further proved to be able to quickly prepare the high quality buffer layer,.4, to simplify the preparation of the buffer layer to reduce the process cost and to improve the engineering of the strip. Practicality, a new structure of fully conductive TiN/SrRuO3 (SRO) buffer layer was proposed and verified by pulsed laser deposition. The growth law of TiN seed layer under different preparation processes was studied. The results of XRD test showed that TiN and SRO had good texture in and out of face, and the surface roughness Rrms of SRO was less than 5 nm.I-V curve to test all conductive buffer layer SRO/Ti. N has good electrical conductivity at normal temperature. The YBCO thin film is prepared by direct current sputtering on it. The R-T curve shows that the resistivity of the superconducting strip near the transition temperature is only about 2 x 10-5 Omega. The structure of the full conductive buffer layer of the YBCO superconducting strip is a new approach to the buffer layer technology of YBCO superconducting strip.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TM26

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 李貽杰;劉林飛;徐達(dá);祝勝萍;王瑩;朱鵬;;REBCO涂層導(dǎo)體制備技術(shù)及其進(jìn)展[J];中國材料進(jìn)展;2011年03期

，

本文編號：2089767