Diffusion of nitrogen in α-Zr and α-Hf

The diffusion coefficients of nitrogen were measured in polycrystalline h.c.p. α-Zr and α-Hf. The nitrogen-implanted zirconium and hafnium samples used for the measurements were annealed at temperatures of 500-7000C and 550-9000C respectively. The nitrogen profiles were probed using the broadening of the (p,αγ) resonance. Doses of 1.8 X 1020 and 1.2 X 1021 ions m-2 were used for the 40 keV 15N implants, but no differences in the diffusivity were observed. Values of 2.50 eV and 2.51 eV for the activation energy and 0.56 cm2s-1 and 0.024 cm2s-1 for the frequency factor were obtained for α-Zr and α-Hf respectively. (Auth.)