A Bi-2212 superconducting solenoid coil with a practical size (78mm in diameter) of bore has been fabricated, employing 300m long Ag-sheathed Bi-2212 rectangular wire. A new heat treatment process, controlling an oxygen partial pressure of 2.4atm, has been developed for crystallization of Bi-2212 in the rectangular wire. The coil has been proven to have high homogeneity in critical current density along the longitudinal direction at the outermost layer, however, the critical current density is lower at the innermost layer. In spite of this drawback, the resulting solenoid coil has stably generated maximum magnetic fields up to 0.40T at 4.2K by transporting current densities up to 1.7×104A/cm2.
