A study of electromigration of nickel in lead

The steady state method was used to study the electromigration of ⁶³Ni in Pb. For the temperature range 180–290°C, and Ni concentration range 0.1–1000 ppm, Ni migrates toward the anode. For dilute samples (0.1 ppm Ni) the effective charge varies linearly with the inverse resistivity from ?6.75 at 188°C to ?4.97 at 289°C. The 1/ρ dependence is given by $\text{Z1 = (1.4 ± 0.3)?(288 ± 13)× 10}{}^{\mathrm{?6}}\text{/ρ}$. The effective charge is a function of the Ni concentration, increasing in magnitude with increasing concentration. For 1000 ppm Ni, |Z1| exhibits a sharp maximum around 260°C; below 230°C electromigration takes place at a much slower rate, probably due to precipitation.