Adhesion strength study of IBAD–MOCVD-based 2G HTS wire using a peel test

A peel test was used to study the adhesion strength of a commercial grade 2G HTS wire which features a characteristic multilayer structure with the rare earth-based MOCVD superconducting film deposited on an IBAD-MgO template. The peel test could be carried out at various peeling angles (from 90° to 180°) and the peel strength of a wire was defined as the steady-state peeling load determined from a load–displacement curve. The test results had good reproducibility and accuracy, making the test a reliable and useful method for studying the adhesion strength of the wire. By characterizing the peeled surfaces the weakest interface in a wire could be identified. The peel strength data of the wire was analyzed together with the performance of the experimental magnet coils fabricated using the wire. The effect of the silver contact layer annealing on the peel strength is discussed.

► A peel test is developed for measuring the adhesion strength of 2G HTS wires. ► The test results have good reproducibility and accuracy. ► The test is used to investigate the wire delamination issue. ► Performance of wet-wound coils is dependent on the peel strength of the wires.