Optimization of the diffusion joint process for the Ag layers of YBCO coated conductors

Effects of uniaxial constant pressures on the joint properties of REBCO coated conductors

“…However, the resistance seems to increase again, when the pressure increased over the above pressure. Further, the lowest resistance of about 6-7nΩcm 2 for SRL specimen [6] is shown in the figure, which means that more improvement in joint resistance is possible.…”

“…Fig.3 (c) also shows uniform Ag microstructure of SRL specimen joined at 10 MPa. Further, when the surface of Ag stabilizing layer was polished beforehand, the diffusion process is promoted effectively, and the low resistance across the joint was achieved [6].…”

“…Among the joint processes, although soldering is a simple joint technique, resistance across the joint is high because it includes resistance of a soldering material, Ag layer and contact resistance of their interfaces. On the other hand, diffusion joining using Ag stabilizing layers, in which an Ag surface is put over the other in a face to face manner, can reduce the resistance across the joint without resistance of a soldering material [1][2][3][4][5][6]. Since some parameters in the Ag diffusion joint process may influence joint resistance, it is necessary to know about factors of the diffusion joint process.…”

Transport AC Losses in Soldered Joint of the YBCO-Coated Conductors

“…Although it is reported that the length of 1 km in the YBCO CC has been achieved by utilizing advanced technologies [3], the joining of YBCO CC tape is still needed essentially for superconducting coil or magnet manufacturing. So far, there are several possible joining techniques presented in literatures [4][5][6][7][8][9][10][11][12][13][14][15], including superconducting joints, non-superconducting joints using a low melting point metal as a soldering material, and diffusion joints. Lots of researches [4][5][6][7][8][9][10][11][12][13][14][15] were focused on how to achieve very small contact resistivity and the good electro-mechanical properties of the joints, while there are few reports on the transport AC loss characteristic in the joints, which is one of the decision factors for future use of the YBCO CC in electric power applications [16][17][18][19][20][21].…”

Study of Factors in Joint Resistance for GdBCO Coated Conductors

“…Joint techniques to connect these coated conductors as well as fabricating long coated conductors with high critical current are essential to manufacture long coated conductor applications [1][2][3][4]. It has been reported that GdBCO have higher critical current (I c ) and critical temperature (T c ) than YBCO [5], so that the development of long coated conductor with high I c in GdBCO has been proceeded extensively [6].…”