工艺过程对Bi系2223相厚膜性能的影响  

INFLUENCE OF THE TECHNICAL PROCESS ON CHARACTERISTIC OF Bi2223 THICK FILM TAPE

作　　者：王玉贵[1] 韩汉民[1] 王顺喜[1] 韩谷昌 

机构地区：[1]中国科学院等离子体物理研究所,合肥230031

出　　处：《低温物理学报》1993年第2期115-120,共6页Low Temperature Physical Letters

摘　　要：工艺研究表明,Bi系2223相超导材料的粉化过程和两次热处理之间的冷压对制备的厚膜性能有很大影响。随粉化时间增加,颗粒度减小,晶粒超导性能的退化越严重。颗粒度越小,沉积在银片上的厚膜越均匀,但退化的晶粒超导性能不能在热处理中得以完全恢复,厚膜的抗磁性能下降。冷压有利于厚膜的致密度增加和2223相层状晶粒的c轴沿压力方向取向,因此有利于厚膜的临界电流密度J_c的提高。但是过大的压力会使品格严重畸变,致使应变能量在晶体内大量积累,热处理后形成其它非2223相,引起超导性能恶化。在银衬底上制备出的超导厚膜,其电流密度在77.3K零场下达到9100A/cm^2,在0.1 T的磁场中为1150A/cm^2;厚膜的J_c随磁场增加迅速下降,说明厚膜中晶粒之间的耦合需要改善,同时也需要在厚膜中引入强的钉扎中心来增强其超导性能。Technical study exhibits that the powdering process of the Bi2223 phase material and the intermediate cold-pressing have a great influence on superconducting performance of the thick film tape. In the powdering process the grain size gradually reduces with increasing grinding time, accompanied by the serious degradation of superconducting properties. Although homogeneous thick film can be deposited on silver tape from the fine powders, the degraded superconducting properties may not be fully restored so that the diamagnetic effect of the thick film is weak- ened. The cold-pressing makes the thick film compact and texture, which are beneficial to improvement of critical current density Jc. However, excessive pressure deforms seriously the grains and accumulates a great deal of crystal strain. After heat treatment, some of these grains transformed into other phase, resulting in the degradation of superconductivity of the thick film. The Jc value of thick film tape prepared by physical deposition method at 77.3K reaches up to 9100A/cm2 in a zero magnetic field and 1150A/cm2 at 0.1T. The sharp decrease of Jc with increasing applied field indicates that not only the connectivity and the orientation among grains need to be improved, but also strong pinning ceter have to be introduced into thick films to obtain a better Jc-H characteristic.

关 键 词：超导体料 厚膜 铋 超导性 工艺 

分 类 号：O511.1[理学—低温物理]