Some inherent limitations of the alloy process for superconducting Nb3Sn

The alloy process for making multifilamentary superconducting Nb3Sn is critically examined. It is shown that the process itself has certain inherent limitations to realize a reasonably high over-all J/sub c/. Further, the microstructure of the material produced by this process is unfavorable for high J/sub c/ and it is shown that at low currents avalanche-like process may occur, driving all superconducting filaments suddenly normal. Attention is drawn to other processes which seem free from the limitations discussed. 12 ref