This study aims to find out the crucial variations in the mechanicalperformance and characterization of Bi-2223 superconducting compounds with thediffusion annealing temperatures interval 650 °C-850 °C by means of Vickers hardness measurementsexerted at the different applied indentation test loads (0.245 N-2.940 N) and derived theoretical findings. Allthe experimental measurement results and theoretical evidences declare that themechanical characterization and performance are obtained to improve with theincrement in the diffusion annealing temperature up the value of 700 °C as aconsequence of decrement in the grain boundary coupling problems, localstructural distortions, grain misorientations, lattice strains, latticedefects, disorders and dislocations in the adjacent layers. Namely, the optimum annealingtemperature of 700 °C resulting in the optimum penetrationof Ni impurities into both the superconducting grains and over the grainboundaries develops the crystallinity of Bi-2223crystal structure. In other words, the surface energy related to thecrack-initiating omnipresent flaws, void/crack propagation and dislocationmovement reduces due to the augmented critical stress value. In this respect,the diffusion annealing temperature of 700 °C develops the mechanical durability, stiffness, ideal fracture and flexural strength. However,after the certain diffusion annealing temperature value of 700 °C, the crystallinity tends to degrade considerably and infact dwelling in the worst crystal structure for 850 °C annealingtemperature. Accordingly, the initialcrack growths, sizes of crack-producing flaws, void/crack propagation anddislocation movement in the copper-oxide consecutively stacked layers reach much more rapidly to the critical speeds due to theincreased stress amplification so that the Bi-2223 compound with the augmentedbrittle behavior breaks at even lower test load.Moreover, it is observed that the presence of optimum nickel impuritiesin the crystal structure strengthens the standard indentation size effect behavior.