Investigation of the mechanical performance of new systems obtained by adding SiO2 to Bi-2212 superconducting system by experimental and theoretical approaches

The structural and mechanical characteristics of the new superconducting substructures obtained by doping the Bi-2212 superconducting inorganic crystal system with SiO2 at varying ratios of 0.00, 0.01, 0.03, 0.05 were investigated in detail by X-Ray Diffraction (XRD) and Vickers microhardness analyses, respectively. As a result of the X-ray analysis of all the samples prepared within the scope of the thesis, it was observed that the Bi-2212 superconducting phase was more dominant than the other phases, and the lattice parameters calculated for all samples were also found to be in agreement with the lattice parameters of the Bi-2212 framework. Characteristic mechanical parameters such as E, Y, KIC, C11, B and D, which should be known for industrial and technological applications of the prepared samples, were determined by load-dependent Vickers microhardness measurements. In addition, it was observed that Vickers microhardness values tended to increase with the increase in the amount of indentation test load for all samples and showed RISE behaviour. Furthermore, using the load-dependent Vickers microhardness measurements and six different theoretical models such as Meyer's law, PSR model, MPSR model, EPD model, Hays-Kendall model and IIC model, the load-independent microhardness values of all prepared samples were calculated. Load-independent microhardness measurements calculated with half of the theoretical models were compared with load-dependent microhardness measurements. As a result, the IIC model was found to be the most successful and appropriate theoretical approach for determining the load-independent microhardness values of the samples for all the samples produced.