tonf cm 2 0 4 gpa and 10 tonf cm 2 1 mpa and sintering under the same conditions 890 u00b0 c for 12 hours in oxygen gas flow as in example 1 certain electric properties tc fig1 tcr fig1 u03c1300k fig1 show no significant difference however the critical current density jc fig1 increases approximately doubled with the increased pressing pressure the increase in jc is observed even at a slight amount of ag as for the mechanical properties the following was observed the flexural strength fig1 increases by about 1 8 times at 50 vol ag and about 1 9 times at 66 7 vol ag the tested flexural strength above 83 3 vol ag shows a decrease after the peak which decrease is believed to be attributable to the occurrence of pores in the sintered samples the measured values are summarized in table 2 as observed above the increased pressing pressure can significantly improve the critical current density jc and flexural strength properties depending on the grain sizes of ybco and ag powders particularly the relative grain size to each other were investigated the following different particle sizes were employed for the experiments using ybco and ag powders having 99 9 purity ______________________________________powder a b______________________________________y sub 1 ba sub 2 cu sub 3 o sub x 325 mesh 100 meshag 100 200 mesh 100 200 mesh______________________________________ case a.