Numerical Analyses of Electrical Contact Characteristics of YBCO Bulk With Silver Deposition

In this paper, an axial symmetric model is constructed to investigate the electrical contact characteristics of YBCO bulk with silver deposited on the contact surface. In order to calculate the thermal-electromagnetic coupling characteristics near the contact spot, a series expression is derived to describe the quenching behavior of YBCO bulk based on the power law and Kim model and a detailed thermal-electromagnetic coupling process is presented according to the physical quenching process of YBCO bulk. During the calculation, the thermal field, the electrical field, and the self-magnetic field are coupled with each other. The calculated contact resistances are compared with the experimental ones. Agreements between them verify the effectiveness of the axial symmetric model. At last, a detailed description about the contact resistance changing from the low-impedance state to the high-impedance state is given based on the calculated field distributions. This work could be helpful to further understanding the electrical contact characteristics of YBCO bulk.