Superconductivity of Solid Solutions of Ti and Zr with Co, Rh, and Ir

A detailed investigation of superconductivity in $\alpha$ and $\beta -\mathrm{T}\mathrm{i}$ and Zr solid solutions with Co, Rh, and Ir showed that $T_c$ rises with increasing valence electron concentration $n$. Small amounts of Co, Rh, and Ir dissolved in $\alpha -\mathrm{T}\mathrm{i}$, or $\alpha -\mathrm{Z}\mathrm{r}$ increase $T_c$ by a factor of 2 to 4. In the bcc phase region of the $\beta -\mathrm{T}\mathrm{i}$ alloys $T_c$ goes through a maximum of 4°K at 90 at.% Ti, which is explained by Matthias' rule.