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通过Ag掺杂降低Sm123/Sm211体系熔点,利用Nd123冷籽晶技术成功制备出具有理想织构的SmBCO/Ag单畴块材.研究了SmBCO/Ag单畴的生长过程,结果发现,相比于未掺杂坯体,掺入Ag后的SmBCO坯体生长速率下降,在所考察的慢冷温区里,生长速率呈不断减小趋势,最终因自发成核而无法继续生长.实验还发现,SmBCO/Ag单畴生长温度窗口随Ag掺量增加向低温区平移.对样品剖面的观察发现,在最高熔化温度保温阶段大量气体未能排出SmBCO/Ag坯体,这些气体在单畴慢冷生长过程中不断向外侧迁移、合并形成宏观可见的孔洞.在单畴生长过程中,这些位于生长前沿的高密度气孔,一定程度上影响了液相和Sm3+离子向生长前沿的供应,是单畴生长速率较低的可能原因.微结构分析表明熔融生长过程中Sm211粒子发生二次晶粒长大现象,长大后的Sm211粒子提供Sm3+离子的能力减弱,导致慢冷生长后期阶段生长速率呈下降趋势.
The melting point of Sm123 / Sm211 system was reduced by Ag doping, and the SmBCO / Ag single-domain block with ideal texture was successfully prepared by using Nd123 cold-seed crystal technology. The growth process of SmBCO / Ag single domain was studied. In the undoped green body, the growth rate of SmBCO green body decreased with the addition of Ag, and the growth rate decreased continuously in the slow cold temperature zone, and finally could not continue to grow due to spontaneous nucleation.The experiment also found that SmBCO / Ag single-domain growth temperature window with the increase of Ag content to the low temperature region of the shift.The observation of the sample cross-section found that a large number of gases failed to expel the SmBCO / Ag blank during the maximum melting temperature holding stage, Which migrated to the outside and merged to form macroscopically visible holes.During the growth of monodomain, these high-density pores located at the frontier of growth affected the supply of liquid and Sm3 + ions to the growth front to a certain extent. Lower the possible reasons.Microstructure analysis showed that during the growth of Sm211 particles, the secondary grain growth occurred, the ability of the grown Sm211 particles to provide Sm3 + ions was weakened, resulting in the growth of slow growth stage Rate showed a downward trend.