| 摘要 |
PURPOSE:To increase critical current density by holding temperature during the temperature rising in a step of heat treatment after filling material for an oxide high temperature superconductive conductor in a metal sheath and thereafter raising the temperature up to the target temperature. CONSTITUTION:Powder being composed of Bi2O3, PbO, SrCO3 and CuO is heat- treated for 8 hours at 800 deg.C, and this is formed in powder-like state, and is heat-treated for 8 hours at 860 deg.C, and again in the above way, is ground into powder-like state. Further after it is heated for 3 hours at 760 deg.C under the reduced pressure of 5Torr, it is filled in a silver pipe and wire drawing and rolling are performed. The wire obtained in this way is heated as temperature is raised at 5 deg.C/minute, at each temperature on the way of temperature rising the temperature rising is once stopped and held for 2 hours and thereafter the temperature is raised up again to 845 deg.C at the temperature rising speed of 5 deg.C/minute. After that, it is heat-treated by holding the temperature for 50 hours in atmospheric condition and thereafter it is cooled down slowly. |
