Bi2212 초전도체와 In 계열 solder의 soldering에서 Ag precoating의 영향

Abstract

In this study, In-base solder was applied to the interface between Bi2Sr2Ca1Cu2Ox(Bi2212) superconductor and Cu-Ni shunt metal at the temperature lower than 150oC. Most of the cases, Bi2212 superconductor was precoated with Ag by electroplating in order to improve the contact properties of the solder layer. When the superconductor was directly soldered on to the superconductor, the solder was easily separated without external force. The shear strength of the contact between superconductor and shunt metal increased from 69.2kgf to 74.4kgf and 80.1kgf, as the current density of the Ag electroplating was changed from 63mA to 96mA and 126mA, respectively. The contact strength also increased to 49.9kgf and 69.2kgf when thickness of the electroplated Ag layer increased to 5mm and 10mm, reapectively.