【摘要】 采用粉末装管法制备了多芯Bi₂Sr₂CaCu₂O_x （Bi-2212）线材,在一个标准大气压（1.01×10⁵ Pa）、氧气气氛条件下对两端封闭和两端开口的线材进行热处理,制备了不同熔化-淬火态及晶化生长后的样品。研究了线材内部气体含量对线材直径、微观形貌以及超导相形成的影响。结果表明,纯氧气氛下烧结的线材芯丝内部残留大量孔洞,大尺寸孔洞形成于线材熔化阶段,并会部分保留到最终线材内部。气体压力促使熔化的液相进入Ag层填充缺陷,导致芯丝之间熔连合并,造成线材织构下降。更多还原

【Abstract】 The Bi₂Sr₂CaCu₂O_x（Bi-2212） multifilament round wires were fabricated by the powder-in-tube technique.Open ends and closed ends wires were heat-treated in flowing O₂ at 1.01×10⁵ Pa.Several samples at various stages of the partial melting process were prepared.The influences of the gas content inside wires on the diameters,microstructures and the phase compositions were nvestigated.The results show that a large number of bubbles are residual during the partial melting process of Bi-2212 filaments in pure O₂ atmosphere.Large-sized pores are formed during the melting of Bi-2212 powders,and some pores remain inside the final wires.High internal gas pressure would cause the molten phase towards the Ag layer to fill the defects,resulting the filament-to-filament bonding and the worse texture.更多还原