Systematic investigation of the effect of the copper layer on the properties of REBCO commercial tape

Nov. 29 15:30-15:55

*Zili Zhang1,3, Huimin Zhang2, Hongli Suo2, Qiuliang Wang1,3
Institute of Electrical Engineering, Chinese Academy of Sciences1
Key Laboratory of Advanced Functional Materials, Ministry of Education, Faculty of Materials and Manufacturing, Beijing University of Technology2
University of Chinese Academy of Sciences3

The effect of stabilizers on the electrical, thermal and mechanical properties of 20 different commercial REBCO tapes from 8 companies are systematically investigated. The resistivity and thermal conductivity in the radial and circumferential directions were focused on. The charging loss and self-protection ability of 20 different commercial REBCO tapes in the no-insulation coils were evaluated via simulation. The three tapes from Superpower with different Cu layer thicknesses were emphatically investigated. The geometry, size, purity, and quality of the Cu layer were analyzed to explore the possible dominant factors affecting the electrical and thermal properties. It was found that piecemeal Cu grains significantly increase and decrease the circumferential resistivity and thermal conductivity, respectively. The dominant factor in the radial direction was more complex, where the thickness uniformity, side Cu layer thickness, and corner contact quality between the Cu and Ag/REBCO could be important factors. Furthermore, the Cu layer purity may be significantly lower than previously thought. Using the resistivity and thermal conductivity values of pure Cu as the Cu layer in the simulation could result in significant errors. Such an investigation can support abundant data for the design of the REBCO magnet or even the choice of REBCO switch or current lead. Another goal was to help the REBCO manufacturers find a feasible way to adjust the resistivity and thermal conductivity, thereby meeting different requirements of the REBCO magnet.

Keywords: REBCO commercial tape, Cu stabilizer, Resistivity, Thermal conductivity