Electrodeposition of Silver Gold Alloys on ${\rm Bi}_{2}{\rm Sr}_{2}{\rm CaCu}_{2}{\rm O}_{8+\delta}$ Ceramics

A metallic coating on the surface of bulk high temperature superconductors (HTS) is a promising alternative in order to increase the HTS stability for large scale applications. The coating provides an evacuation path for the heat generated by hot spots within the HTS, which improves their thermal stability. This is even more evident in thick films geometries, which are frequently used in fault current limiters. In this paper, silver-gold alloys have been deposited on 1.8 mm in diameter Bi-2212 textured bars using an electrodeposition technique in non-aqueous solvents. The deposition parameters have been adjusted to obtain a coating of different alloys with gold contents in the range 0-5 at % and with a thickness up to 45 mum. Electrical and thermal measurements have been performed. The results show the possibility of controlling the thermal and electrical conductivities of the composite material by adjusting the layer thickness and composition of the metallic coating.