TSMTG法制备GdBCO块材及对其性能的研究
发布时间:2018-05-08 23:14
本文选题:顶部籽晶熔融织构法 + 单畴GdBCO超导块材 ; 参考:《陕西师范大学》2010年硕士论文
【摘要】: 顶部籽晶熔融织构法(TSMTG)是制备钇系高温超导块材的重要技术之一。在钇系超导材料中,GdBCO超导体具有较高的临界温度、较大的无阻载流能力和较强的磁通捕获能力,因而在超导电机、超导磁悬浮列车、磁浮轴承、永磁体、储能飞轮等方面都具有巨大的应用价值。 本文采用固相烧结法制备出比较纯的初始粉体,采用TSMTG工艺制各出掺杂不同BaCuO2 (Gd011)含量的GdBCO单畴超导块材,并对该类超导块材的微观结构和磁悬浮力等性能进行了分析;其次,通过在GdBa2Cu3O7-δ(Gd123)初始粉体中掺杂不同含量的Y2O3粉体,制备出了系列(Gd, Y)BCO超导块材,在对其宏观形貌,微观结构和磁悬浮力性能进行分析的基础上,研究了工艺参数对超导块材形貌和性能的影响。 在制备GdBCO超导体的过程中,需要用到GdBa2Cu3O7-δ(Gd123)、Gd2BaCuO5(Gd211)和BaCuO2 (Gd011)等初始粉体。这些粉体均采用多次研磨多次烧结的工艺,三种粉体的烧结温度分别为940℃,920℃,910℃。 研究了BaCuO2添加对TSMTG法单畴GdBCO块材的生长形貌、微观结构以及磁悬浮力性能的影响。在固定Gd123与Gd211摩尔比为1:0.4时,当Gd011掺杂量在0-0.5mol范围内时,Gd011的掺杂对其表面形貌影响不大,均可制备出单畴GdBCO块材。对整个组分进行的微观结构分析结果表明:随着Gd011掺杂比例的增加,Gd211粒子的尺寸在逐渐地减小。这是由于过量Gd011致使Gd211在液相中溶解的结果。另外,我们研究了Gd211粒子在准单畴GdBCO超导块材中的分布。对掺杂Gd011为0.2mol的准单畴样品分析结果表明,Gd211粒子在整个样品中分布都是不均匀的。对该系列超导块材磁悬浮力测试的结果表明,Gd011的含量对GdBCO超导体的磁悬浮力有明显影响,在固定Gd123与Gd211摩尔比为1:0.4时,掺杂BaCuO2的最佳比例约为0.2mol。 研究了Y2O3添加对TSMTG法(Gd, Y)BCO超导块材的生长形貌、微观结构以及磁悬浮力性能的影响。当在Gd123初始粉体中添加Y2O3质量分数较小时,畴区长满整个样品;当两者质量比例超过100:4时,随着添加的Y2O3质量的增加,样品表面所形成的单畴区域面积逐渐减小;当两者质量比例超过100:15时,样品完全停止生长。对其生长前沿成份分析结果表明,成份偏析是导致晶体生长停止的主要原因。对掺杂Y2O3粉体的样品,随着掺杂量的增加,镶嵌在样品中的RE211粒子密度逐渐增加,同时RE123相含量逐渐减少。磁悬浮力测试结果表明,Y2O3的含量对(Gd, Y)BCO超导块的磁悬浮力有明显影响,其最佳添加质量比为Gd123:Y2O3=100:4。温度参数的选择对(Gd, Y)BCO超导块形貌和性能的影响也很大,最高融化温度过高过低都不好,通过多次调整得到最佳熔化温度为1070℃。生长温区的选择直接关系到样品生长的好坏,通过四组不同的生长温区试验得到相对最佳生长温区。
[Abstract]:Top seed melt texture method (TSMTG) is one of the important techniques for preparing yttrium high temperature superconducting bulk materials. In yttrium superconducting materials, GdBCO superconductors have higher critical temperature, larger unstoppable current-carrying capacity and stronger flux trapping ability, so they are used in superconducting motors, superconducting maglev trains, maglev bearings, permanent magnets, etc. The energy storage flywheel has great application value. In this paper, the relatively pure initial powders were prepared by solid-state sintering, and GdBCO single domain superconducting bulk materials doped with different BaCuO2 Gd011) were prepared by TSMTG process. The microstructure and magnetic suspending force of these superconducting blocks were analyzed. A series of Gd and Y)BCO superconducting bulk materials were prepared by doping different contents of Y2O3 powders into the initial GdBa2Cu3O7- 未 Gd123) powders. Based on the analysis of their macroscopic morphology, microstructure and magnetic suspended buoyancy properties, a series of superconducting bulk materials of GdBa2Cu3O7- 未 Gd123 were prepared. The effect of process parameters on the morphology and properties of superconducting bulk was studied. In the preparation of GdBCO superconductors, the initial powders, such as GdBa2Cu3O7- 未 (Gd123O5 (Gd2CuO5) Gd211) and BaCuO2 (Gd011), are needed. The sintering temperature of the three kinds of powders is 940 鈩,
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