Silver-sheathed BiPbSrCaCuO wires were f a b r ic a t e d t h r o u g h t h e p o w d e r -i n -t u b e method. Jc-B p r o p e r t i e s , microstructures and Jc-strain properties wcre evaluated. Prototypes of coils and current leads were made and tested successfully.Critical current densities a t 77.3 K were 4 . 7~1 0~A/cm2 in a zero magnetic f i e l d , 3 . 1~1 0~ A/cm2 a t 0.1 'I'csla and 1 . 1~1 0~ A/cm2 a t 1 Tesla. In liquid He, 4.2 K, these wires can c a r r y 1 . 0 3~1 0~ A/cm2 a t 23 Tesla. J c and .Jc-B enhancements a r e due t o grain boundary improvements. Detailed investigation of Jc-B characteristics in magnetic fields, especially increasing and dccreasing f i e l d s , revealed t h a t h i s t o r y e f f e c t behaviors caused by weak l i n k s disappeared with improvements of grain boundary characteristics a t both temperatures. 1296 multifilamentary wires were shown t o sustain over 70 % of J c o even a f t e r a s t r a i n of up t o 0.GG % repeated 10 times. These r e s u l t s show f u t u r e possibilities of f l e x i b l e c a b l e s and r e a c t & windprocessed magnets. P r o t o t y p e s of c o i l s and c u r r e n t leads were fabricated using 20 m long wires. One c o i l showed critical currents of 54.2 A a t 77.3 K and 367 A a t 4.2 K. This coil generated B, of 142 Gauss a t 77.3 K and 87G Gauss a t 4.2 K. Critical c u r r e n t p r o p e r t i e s were investigated with back-up fields of up t o 990 Gauss a t 77.3 K and 3.7 Tesla a t 4.2 K. A prototype of react & wind-processed coil was demonstrated using o v e r 4 m I o 11 g mu 1 t i f i 1 am e n t a r y w i r e s , a n d s u c c e s s f u 1 l y produced enough magnetic f i e l d t o r o t a t e c o p p e r windings between s t e e l cores. 50 cm long c u r r e n t leads were made and t e s t e d a t 77.3 K and proved t o carry 242 A, showing overall current d e n s i t y of 2000 A/cm2 including silver-sheath.
[reaction: see text] The specific silylation of aryl iodides and bromides with triethoxysilane (EtO)(3)SiH in the presence of NEt(3) and a catalytic amount of [Rh(cod)(MeCN)(2)]BF(4) provides the corresponding aryltriethoxysilanes in high yield.
The effect of axial strain, F,, on the critical current, I,, of Nb3Al "Cable in Conduit" (CIC) subconductors has been measured firstly at I, 5 10 kA and a magnetic field of B = 12 T a t KfK, Karlsruhe. Like comparable NbaSn CTC cables this conductor exhibits a maximum of I, at e, = 0.7 YO, but the degradation of I, at e, = 0 and B = 12 T being only 20% for Nb3Al in comparison to 50 96 for the NbsSn cables. Furthermore, the I, vs Ea characteristic behaves completely reversible under both loaded and unloaded conditions up to the measured strain of e, = 1.7%. The Nb3A1 CIC subconductor has been developed within the 10 k N 1 2 T class for fusion magnets a t JEARI. A tripleted cable consisting of 36 strands was inserted into a circular stainless steel conduit with 30 c?c void fraction and then heat treated. JR processed Nb:{Al wires were used for the basic strands.
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