Thermal conductivity of 2G HTS wires for current lead applications

We have studied the thermal conductivity of several 2G HTS coated conductor wires produced by AMSC's RABiTS^TM/MOD processes. The measurements employed a non-steady state method in which the sample is connected to a cold head on one end and a copper block on the other end. The heat capacity of the copper block is used to determine heat flow through the sample as the cold head slowly warms up. Measurements were done at temperatures ranging from 10 K to 130 K on 2G wires made with a Ni 5at%W substrate and different lamination architectures. The focus of the investigation was on the effects of lamina material type, thickness of the silver layer and alloyed silver. The data show that 2G wires can be 3 times less thermally conductive when compared to 1G BSCCO wires with a Ag-Au matrix, making them excellent candidates for use in current lead applications.