4568

4296

كارشناسي ارشد

فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1387

دوازده ، 209 ، [II] ،ص: مصور ، نمودار

ص.ع. به: فارسي وانگليسي

هادي سلامتي

پرويز كاملي

88/4/31

علي اكبر بابايي ، فرهاد شهبازي

1396/09/12

كتابنامه

فيزيك

ID4296

به فارسي وانگليسي : قابل رويت در نسخه ديجيتال

The effect of the substitution of Sr by Ba in two series of Bi 2223 superconductors And optimization of Bi 2223 Ag superconducting tapes Toktam morshedloo t morshedlo@yahoo com 14 3 2009 Department of Physics Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiDr Hadi Salamati salamati@cc iut acAbstractThis thesis of consists two parts In the first part substitution of Ba for Sr in Bi 2223 superconductor and in thesecond part fabrication of Bi Pb 2223 Ag superconductor tape by different conditions for finding optimizedparameters of prepration process have been investigated To investigate the effece of the partial substitution of Sr byBa in the Bi 2223 superconductor and studying the relation of nominal compoisition of the samples two series ofsamples with different nominal compoisition A Bi1 8Pb0 4 Sr2 x BaxCa2 2Cu3Oy x 0 0 1 0 2 0 3 and B Bi1 66Pb0 34Sr2 x BaxCa2Cu3Oy x 0 0 1 0 2 0 3 0 4 0 5 have been preparated by solid state reaction method TheXRD and SEM analysis and the results of the electrical resistivity and AC susceptibility measurements show thatthe relative composition of initial elements used in Bi 2223 is essential to the site that is selected by the Ba ions InA sery Ba doping up to x 0 1 would improve the phase formation of Bi 2223 and improve the superconductivityproperties of the grains and grain boundaries The flux pining force in the grain boundaries has been improved bysmall precipitates of Ba rich phases as point deffects In B sery although Ba doping up to x 0 1 would enhance thephase formation of Bi 2223 but it would decrease the coupling between the grain and superconductivity propertiesof this systems by producing more impure phases The presence of lower TC phases would begin to appear forx 0 1 in both system The superconductivity properties and the phase formation of Bi 2223 would decrease as theBa concentration increases In second part six different nominal compositions with two different preparationmethods 1 solid state reaction method and 2 sol gel method have been preparated for fabrication ofsuperconductor tape Five powder of samples have been selected and five tapes have been fabricated from them The2212 has been the major phase in these phases The XRD and SEM analysis and the results of the electricalresistivity and AC susceptibility measurements show that the tape that is prepared from the initial powder withBi1 89Pb0 41Sr2 01Ca2 23Cu3 03O10 x composition and produced by the solid state reaction method had better behavioramong all of the prepared tapes The optimization conditions for preparation were as follow sintering at 835oC for200h in air with several intermediate pressing final thickness of 0 4 mm and with post annealing at 825oC for 30hafter the last step of sintering Key wordssubstitution of Sr by Ba Bi 2223 superconductor Bi Pb 2223 Ag superconductor tape solid

هادي سلامتي

پرويز كاملي

علي اكبر بابايي ، فرهاد شهبازي