摘要
采用主相为２２１２＋ＣａＣｕＯ２的所谓双粉作为前驱粉，用标准的粉末套管（ＰＩＴ）工艺制备了３７芯、６１芯和８５芯Ｂｉ－２２２３银包套多芯带材．研究发现：采用双粉装管缩短了２２２３成相时间，仅用４０ｈ即获２２２３纯相．前驱粉中较大尺寸２２１２片状晶的存在有益于Ｃａ，Ｃｕ传质和２２２３织构的提高．通过对加工工艺的精确控制，可有效防止芯丝的不均匀，清除妨碍长带制备的芯丝“香肠”状现象．首次实现了双粉法制备高性能的Ｂｉ－２２２３／Ａｇ长带，长带性能的均匀性和重复性都有较好保证．所制备的０．２４ｍｍ×４ｍｍ尺寸短样在７７Ｋ时Ｉｃ＝５３Ａ（Ｊｃ约为２．７×１０４Ａ／ｃｍ２），达国际先进水平，２０ｍ长样Ｉｃ＝３５Ａ，并实现批量化生产．
Many studies have shown that the phase assemblage of starting powders influences
the phase evolution of the 2223 phase; but it is quite difficult to control the phase balance in
precursor powders using a singlepowder process. In this study, (Bi,Pb)2212 and CaCuO2 are
formed as separate intermediate phases, then mixed and processed together within a silver
sheath. The phase transformation kinetics, microstructure and transport properties of the
resulting tapes are strongly dependence on the phase content of the precursor powders. Nearly
pure 2223 can been produced when sintering for as little as 40 h, using (Bi, Pb)2212 and
CaCuO2 presursors, and the fraction of nonsuperconducting phases seem to become minimum
at the boundary of the oxide core. The effects of mechanical deformation and heat treatment
cycles on silvercore interfaces and critical current densities in 37,61 and 85 filament tapes
have been studied for the tapes fabricated using the twopowder process. A smooth Agoxide
interface has been obtained through accurate control of the pass reduction ratios. This
experiment demonstrates that the existence of large platelike 2212 grains in the presursors can
accelerate the diffusion of Ca, Cu during sintering stage and increase the degree of texture of
2223 grains.Tapes with a thickness of 024 mm can be made using flat rolling without any
sausaging effect. Jc values of 30104 A/cm2(Ic=53 A) and 17104 A/cm2(Ic=35 A) at 77 K and self
field are achieved for rolled short samples and tapes 20 m long, respectively.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
1999年第3期155-160,共6页
Rare Metal Materials and Engineering
关键词
双粉法
多芯带材
超导体
制备
PIT
twopowder process, Bi2223/Ag tape, pass reduction ration, phase transformation
