The following niobium alloys were studied: Nb-1wt % Zr, Nb-1.8wt % Ti, Nb-7.5wt % Ta and Nb-10wt % Hf-1wt % Ti(C-103). It is important to note that all of these are commercially available; Nb1.8wt % Ti and Nb-7.5wt % Ta were developed specifically for the superconducting market. However, the Nb-Hf alloy is not, which has been developed in the aviation field for four decades. If the alloy C-103 can be used in the present invention, it will be very fortunate, with great practical and commercial value, especially considering the time and money that such work usually requires.
The benefits of using niobium alloys such as Nb1wt % Zr, Nb1.8wt % Ti, Nb7.5wt % Ta and Nb-10Hf-1wt % Ti were confirmed in our study. A substantial increase in the layer thickness of Nb3Sn compared to pure niobium was seen in all cases. The increase in Nb-10Hf-1wt % Ti is by far the largest.
The CuSn matrix alloys studied are Cu-19Sn-0.37Ti, Cu-23Sn-0.25 ~ 4wt % Ti and Cu-23Sn-0.5 ~ 2wt % Mg. Any increase in Ti and Mg above 2wt % was found to result in incomplete penetration. It is strange that this phenomenon occurs at this level of alloy addition, and must be related to the change in the surface tension of the bath and its limited solubility, even at 1100℃. In addition, alloys with less than 0.5wt % Ti were found to be equally effective in promoting the growth of Nb3Sn. The reason should be explained that Nb3Sn reacts at 700℃±50℃ and the solubility limits of Ti and Mg are lower at lower temperatures. For this reason, the optimal alloy matrix component should be between 15-25wt % Sn plus 0.2-2.0wt % Ti, and the rest is copper.
It has been observed that copper rods dissolve almost immediately when inserted into an Sn bath at 1100℃. Based on this finding, it is assumed that this essentially instantaneous dissolution also occurs in the copper matrix and that the Sn matrix can be effectively substituted for the copper. In order to limit % Sn to the ideal range of 13-40wt %, a Cu-Sn alloy can be used instead of pure Sn. Adding copper should slow down the alloying process, so it is important to determine limits on bath composition and time. Refer to FIG. 15a, according to this example vanadium, the sample of the blank is selected according to the non-etched state 100 after drawing, and the sample is immersed in the pure Sn bath 102 for 2, 4, 6 and 8 minutes at 1100℃. The wire diameter is 1mm, and the blank segment contains 2508 8 micron niobium filaments.
