Effects on residual stresses of annealing parameters in high-temperature ZrO2 insulation coatings on Ag/Bi-2212 superconducting tapes using finite element method

In the present work, we focus on effects of residual stresses of annealing parameters and fracture behavior in high-temperature ZrO2 insulation coatings on Ag/Bi-2212 superconducting tapes using the finite element method. High-temperature ZrO2-based insulation ceramic coatings were produced on Ag and Ag/AgMg sheathed Bi-2212 superconducting tapes by the reel-to-reel sol–gel technique for magnet technology. The samples produced were characterized using scanning electron microscopy (SEM). These coatings are exposed to thermal loading under several annealing conditions. The residual stresses in 8-μm-thick coatings, as well as changes during thermal cycling, were simulated by finite element analysis (FEA). It was found that the shear stress values of ZrO2 coatings in the interface were very low, and the maximum shear stress was 47 Pa for 8-μm-thick coatings. It was determined that the highest fracture intensity was 1.09×10−4 MN m−3/2, and the fracture intensity decreased as a function of distance from the initial crack.