Self-Diffusion in fccγ-and bccδ−Cerium

The serial sectioning method was used to study self-diffusion in cerium metal. In the fcc $\gamma$ phase, $D=0.6\mathrm{}{e}^{-\frac{36600}{\mathrm{RT}}}$ ${\mathrm{cm}}^2$ ${\sec }^{-1\mathrm{}}$, and in the bcc $\delta$ phase, $D=1.2\mathrm{}\times {10}^{-2\mathrm{}}{e}^{-\frac{21500}{\mathrm{RT}}}$ ${\mathrm{cm}}^2$ ${\sec }^{-1\mathrm{}}$. The diffusion parameters in the fcc structure are compatible with a normal vacancy mechanism. The high diffusivities and low activation energy in the bcc phase are characteristic of diffusion behavior in anomalous bcc metals. Similarities with self-diffusion in bcc $\epsilon -\mathrm{plutonium}$ are stressed.