Physica C 162-164 (1989) 885-886 North-Holland MICROSrRILTURE AND ~£LTIVITY OF SHOCK PROCEgBED HIGH TC S U P ~ R ~ Z.IQBAL , N.~A~qI #, K.A.JOHNSON +, K.V.RAO++, B.L.RAMAKRIE~qNA , Renu SHANMA, and H .~ W F. REID~ Allied Signal Inc., Corporate Technology, Morristown, N.J. 07960, U.S.A. ~ETR, New Mexico Institute of Mining and Technology, Socorro, N.M. 87801, U.S.A. + Los Al0~nos National Laboratory, Los Alaraos, N.M. 87545, U.S.A. ++-Dept of Solid State Physics, Royal Institute of Technology, Stockholm, Swed_~ ** Dept of Chemistry and Center for Solid State Science, Arizona State Univ. ,Tempe AZ85287, U.S.A. Explosive shock compaction of furnace synthesized i micron size powders of YBao~O~ and BigSrgCa- C~90~ have been carried out both in the planar and cylindrical gecraetries. In ~otl$ ~ases inter~st- ir~ ~icrostr~ctures and near theoretical packing densities are obtained. Hc~ever bulk supercot~k~t- ivity is degraded_~__ but restored with some interesting changes on reannealing. The tetragonal and ~ic~2Ba2CuO phases were successfully shock-synthesized in the time domain of micro- seconds at 1001dSar. Th~ products obtained ra~ged in phase purity from 85 to nearly 1007o. The shock- synthesized tetragonal phase is a bulk su~~tor with T (zero) of 55K.P~Lgh resolution elecL~on microscopy shows double copper layer defects in the shock synthesized tetra~ TIgBagCuOA.The importance of shock induced defects and microstr~ctures in the magnetic flux pirmln~ ~ha~isms are briefly discussed. i. INTRODUCTION Shock compression has a high potential for processing ~rcortluctors to desired practical shapes and for synthesizing known and new super- conductors. In this process a dynamic pressure pulse in the i0-i000 kbar range can be applied for the duration of a microsecond. Another imp- ortant feature is the rapid thermal quench rate (109K/s) which would allow the synthesis of met- astable supercortlucting phases. Shock process- ing has been applied to the new supercor~ ~tors and the initial results are promising (1,2).For example, a composite coil of the YBa2Cu307(YI23) material has been made via shock compaction that is ¢a~r~ble of carrying up to 13000 A/=m2 at 77K in 0 field(3). In this paper we will discuss the superconducting properties and the mierostruct- ures introduced via shock in Y123 and Bi2Sr2Ca- O~208 (Bi 2212). In addition, we will present data showing the successful shock synthesis of the TI2Ba2CuO6 (T12201)phase and the possible synthesis of a metastable cubic Tl-doped barium cuprate phase. 2. MICROSTRLL'IURE Y123 powders of i rr~cr~n average grain size wer~ shocked in a variety of geometries and shock pressures. Near theoretical density and reasonably crack-free compacts were obtained at 60% initial packing density and about 120 kbar pressure in the cylindrical geometry. ~ shows high twin density domains formed by the rapid quench from the tetragonal to orthorhorbic phase X-ray diffraction showed orthori~daic symmetry with some line broadening due to crystallite fracture. Bi2212 powder of i-i0 micron grain size corn- • ~ = " i Fig.l HKI~H image of shocked T12201 showing double copper defect 0921-4534/89/$03.50 © Elsevier Science Publishers B.V. (North-Holland)