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New Fabrication Process of High-Tc Oxide Superconductors via Melt and Their Characterization

熔体制备高温氧化物超导体新工艺及其表征

基本信息

批准号：
02453070
负责人：
MINAMI Tsutomu
金额：
$ 4.42万
依托单位：
University of Osaka Prefecture
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Preparation techniques for high-Tc oxide superconductors via melt have attracted much interest because dense and homogeneous materials are easily obtained. The purpose of this research project is to establish the preparation processes via melt to obtain excellent high-Tc superconductors with various morphologies. The following results were obtained.1. Viscosities were measured for the Bi-Ca-Sr-Cu-O glasses with various compositions in order to predict the compositions for fiber drawing. The Bi-Pb-Ca-Sr-Cu-O glass fibers were successfully prepared using a thermal-image furnace.2. The crystallization process was studied for the Bi-based superconductor precursor glasses ; the phases of Ca_2PbO_4 and CuO formed during heat treatment, which enhanced the partial melting of the samples, was found to play an important role in the formation of the 110 K phase.3. The optimum heat-treatment temperatures T_<OPT> was observed in the metal-doped superconductor glass-ceramics in the systems Bi-Pb-M-C … More a-Sr-Cu-O(M : various metals). The metal dopants were found to affect the temperature at which a partial melting occurred and therefore affect T_<OPT>.4. The introduction of the multi-step heat-treatment process, by which the nucleation was expected to be accelerated, was found to enhance the critical current density of Bi-Pb-Ca-Sr-Cu-O glass-ceramics obtained from rapidly quenched precursor glasses.5. Preparation condition of high-Tc thick films by melt solidification was optimized. Rapid cooling of the molten samples to the heat treatment temperature was the most important factor in all the preparation steps.6. Metal doped superconductor thick films of Bi-Pb-M-Ca-Sr-Cu-O(M=In, Mo, Nb, Sb, Sn, V, W) were prepared using melt-solidification procedure. The dopants lowered the partial melting temperatures and thus lowered T_<OPT> for the formation of the 110 K phase.7. Fine powders in the system Bi-Pb-Ca-Sr-Cu-O were successfully prepared by the spray-pyrolysis method. The particles produced were spherical and their size could be controlled from submicrometer to micrometer by changing the concentration of the starting solutions. Less

熔融法制备高Tc氧化物超导体因其易于获得致密、均匀的材料而受到广泛关注。本研究计画的目的是建立熔融法制备高温超导体的方法，以获得不同形貌的高温超导体。得到以下结果.测量了不同组成的Bi-Ca-Sr-Cu-O玻璃的粘度，以预测拉丝的组成。利用热成像仪成功制备了Bi-Pb-Ca-Sr-Cu-O玻璃纤维.研究了Bi系超导体前驱体玻璃的晶化过程，发现热处理过程中形成的Ca_2PbO_4和CuO相对110 K相的形成起着重要作用，促进了样品的部分熔融.研究<OPT>了Bi-Pb-M-C系金属掺杂超导微晶玻璃的最佳热处理温度T_1 ...更多信息 a-Sr-Cu-O（M：各种金属）。发现金属掺杂剂影响发生部分熔化的温度，因此影响T<OPT>_4。通过引入多步热处理工艺，加速了晶核的形成，提高了由急冷前驱体玻璃制备的Bi-Pb-Ca-Sr-Cu-O系微晶玻璃的临界电流密度.优化了熔体凝固法制备高Tc厚膜的工艺条件。在所有制备步骤中，快速冷却熔融样品至热处理温度是最重要的因素.采用熔融凝固法制备了金属掺杂的Bi-Pb-M-Ca-Sr-Cu-O（M=In，Mo，Nb，Sb，Sn，V，W）超导厚膜。掺杂剂降低了部分熔化温度，从而降低了<OPT>形成110 K相的T_。采用喷雾热解法成功地制备了Bi-Pb-Ca-Sr-Cu-O系超细粉体。所制备的颗粒为球形，其尺寸可以通过改变起始溶液的浓度从亚微米到微米进行控制。少