Effect of a Heat-Conducting Epoxy Coating on Electrothermal Characteristics of High-Temperature Superconducting Wires at Phase Transitions

The effect of an epoxy coating on characteristics of superconducting wires in various phase states is studied. It is shown that the epoxy compound layer with high thermal conductivity does not decrease the critical current and increases thermal stability of the HTS tape to local perturbations; therefore, the heat release during its transition to the resistive and normal state occurs over the entire superconductor length. In the normal state at a current to 700 A and electric fields to 10 V/m, the heat release in a wire is completely removed to liquid nitrogen, and wire overheating is steady-state and does not exceed 80 K. At the electric field increases, the heat sink transforms to an inefficient film mode, which results in a temperature increase and thermal decomposition of the sample.