Vacuum heat treatment effects at 850 C for (3, 6, 9 and 12 h) on the crystalline structure and superconducting, as well as on the
mechanical properties of Bi4Sr3Ca3Cu6Ox (BSCCO) have been studied. The highest critical transition temperature Tc 102 K was achieved
at annealing time tann = 9 h. This maximum value is attributed to movement of excess oxygen from annealed sample. Phase examination
by X-ray diffraction (XRD) revealed that the gradual formation of the high-Tc phase (2223) due to the prolongation of annealing time
up to 9 h. Thereafter, the high-Tc phase starts degrading and Tc reduces. The distortion of the 2223 phase is suggested by the broadening
of the different XRD peaks. Also, at the same above annealing time (9 h), SEM observation shows good quality plate-like crystal with
relatively oriented. On the other hand, the Vickers microhardness (VHN) measurements was found to be dependent on the annealing
conditions, a tremendously increase of VHN value 1.92 GPa (0.25 N) at tann = 9 h. This substantial increase is ascribed to improvement
of the thermal conduction and stabilization of temperature distribution between superconducting grains.