GROWTH OF Bi-2223 PHASE FROM TEXTURED Bi-2212 PHASE SOLIDIFIED IN HIGH MAGNETIC FIELDS

1)添加Ag_2O，MgO和B_2O_3对Bi-2223相在强磁场下凝固后的显微结构和超导性能的影响：添加5%MgO和5%Ag_2O对Bi-2223相在强磁场下凝固后的织构略有改善，但添加B_2O_3对织构没有改善。MgO的加入也提高了由VSM测量的磁滞回线的ΔM估算的Jc值。2）强磁场下Bi-2201相的织构和超导性能：非化学计量比Bi-2201相在10 T的磁场下凝固。获得了大的、c轴取向良好的Bi-22 O 1相。在各向异性方面，垂直于磁场方向流动的样品的Jc值比平行于磁场方向流动的样品的Jc值大10倍左右，而在无磁场条件下凝固的Bi-22 O 1样品中没有观察到织构。3）强磁场烧结过程中Bi-2223相的形成和织构：在10 T磁场下，在835 ~ 860 ℃温度范围内烧结样品。在855℃以下，随着烧结温度的升高，Bi-2223相的织构得到改善，但Bi-2223相的体积分数却随着烧结温度的升高而降低。在液相存在的860℃烧结后，没有观察到Bi-2223相，而只得到了取向良好的Bi-2212相。

1) Effect of Ag_2O,MgO and B_2O_3 additions on microstructure and superconducting properties of Bi-2223 phase after solidification in high magnetic fields:5%MgO and 5%Ag_2O additions improved the texture of Bi-2223 phase slightly after solidification in high magnetic fields but B2O3 addition never improved. MgO addition also improved the Jc value estimated from ΔM of hysteresis loop measured by VSM.2) Texture and superconducting properties of Bi-2201 phase solidified in high magnetic fields:Non-stoichiometric Bi-2201 phase were solidified in a magnetic field of 1OT. A Large, well c-axis aligned Bi-22O1 phase was obtained. As for the anisotropy, Jc flowed perpendicular to the applied magnetic field is about 10 times larger than that flowed parallel to it. On the contrary, no texture was observed in the Bi-22O1 sample solidified without a magnetic field.3) Formation and texture of Bi-2223 phase during sintering in high magnetic fields:Samples were sintered in the temperature range from 835 to 86O℃ in a magnetic field of 10T. Texturing of Bi-2223 phase was improved with increasing sintering temperature up to 855℃, however the volume fraction of Bi-2223 phase decreased with increasing sintering temperature. No Bi-2223 phase was observed after sintering at 860℃ where the liquid phase existed, but only well-aligned Bi-2212 phase was obtained.