The confusion over the growth rate of the Nb3Sn superconductor compound according to the bronze technique was addressed. Furthermore, a possible explanation for the corrugated structure of the product phase in the multifilamentary structure was considered. Kirkendall marker experiments were conducted to study the relative mobilities of the species, which also explained the reason for finding pores in the product phase layer. The movement of the markers after interdiffusion reflected the fact that Sn was the faster diffusing species. Furthermore, different concentrations of Sn in the bronze alloy were considered to study the effect of Sn content upon the growth rate. Based upon the parabolic growth constant at various temperatures, the activation energy for the growth was determined.

Interdiffusion and Growth of the Superconductor Nb3Sn in Nb/Cu(Sn) Diffusion Couples. A.K.Kumar, A.Paul: Journal of Electronic Materials, 2009, 38[5], 700-5